Pith. sign in

REVIEW 3 major objections 6 minor 1 cited by

Configurational forces explain echelon cracks in soft materials

T0 review · 3 major / 6 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read This paper shows that configurational forces computed on idealized echelon crack geometries explain both the magnitude and direction of crack growth in soft materials under mixed-mode I+III loading, via facet tilting, local binormal…

desk verdict Solid computational study of configurational forces on idealized echelon cracks, but the title overclaims: geometry is input and the F_BN mechanism rests on a single tip profile. read the letter →

arxiv 2507.12247 v1 pith:KFHGLPEX submitted 2025-07-16 cond-mat.soft

classification cond-mat.soft MSC 74R1074B2074S05
keywords echeloncracksmixed-modeI+IIIfractureconfigurationalforcessofthydrogelfacetcoalescencefiniteelementmethodcracksegmentation
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper aims to explain why echelon cracks—the segmented, tilted facet patterns that form when a tensile crack is loaded with out-of-plane shear—grow the way they do in soft materials, using configurational forces rather than linear elastic fracture mechanics. It constructs idealized finite-element models of echelon crack geometries informed by X-ray tomography of hydrogels and computes the configurational force (the energetic driving force for crack advance) along the crack front before propagation. The central claim is that this single field captures both the magnitude and direction of facet propagation: facet tilting controls the driving force, local binormal shear $F_{BN}$ causes the propagation direction to deviate from LEFM-based scaling, facet spacing modulates whether neighboring facets amplify or shield each other, and facet coalescence redistributes forces asymmetrically. If correct, this gives a material-model-independent way to predict echelon crack morphology in soft, quasi-brittle solids, where LEFM assumptions fail.

What carries the argument

The Configurational Force Method: the Eshelby stress tensor $\Sigma = \Psi I - F^T \partial \Psi/\partial F$ is evaluated from a finite-element solution of the finite-strain neo-Hookean boundary value problem, and its divergence is integrated against nodal basis functions to yield nodal configurational forces $F^{CNF}_A$; summing these forces along the crack front and dividing by arc length gives the energetic driving force per unit length whose magnitude and direction indicate propagation tendency and preferred direction. The idealized echelon geometry (a parent crack with tilted finger-like facets of profile $f(y)=\pm\sqrt{1-2y+2y^3-y^4}/2$, symmetric angular spacing $\Lambda$, and tilting angle $\varphi$) and a local coordinate frame $(\hat{T},\hat{N},\hat{B})$ at the crack front are the other central objects; the off-diagonal deformation-gradient component $F_{BN}$ is the local shear measure invoked to explain deviations from LEFM scaling. A molecular-dynamics-based mesh relaxation smooths the coalescence junction between facets.

What would settle it

Compute the configurational forces on the same echelon geometry while varying the facet tip profile (e.g., sharp versus blunted tips, different $f(y)$) and check whether the evolution of $F_{BN}$ and the angle $\beta$ tracks the tip-shape changes; if $\beta$'s deviation from LEFM scaling persists without a corresponding $F_{BN}$ trend, the claimed mechanism is false. Alternatively, measure the actual propagation directions of echelon facets in a hydrogel under mixed-mode I+III loading using time-resolved X-ray tomography and compare them with the configurational-force directions predicted here, including the predicted sign reversal of $\beta$ for small facet tilting angles.

Watch

Extended reading notes

Core claim

The paper's central discovery is that the configurational force vector at the crack tip, computed as a nodal force from the Eshelby stress on an idealized echelon crack geometry, characterizes both the tendency and the preferred direction of propagation for maximal energy release rate. Under pure tension, the force magnitude is higher for smaller facet tilting angles $\varphi$, and the binormal component dominates while the tangent component is negligible, meaning facets propagate while keeping their tilt. A non-zero normal component produces an angle $\beta$ between the force and the facet plane that increases under tension and decreases under torsion, even reversing sign for $\varphi \leq 20^\circ$ at large torsion; the paper attributes this deviation from the LEFM scaling to local shear deformation $F_{BN}$ in the binormal direction. The paper further shows that facet spacing modulates the driving force on both facets and planar segments, with a critical spacing below which shielding dominates, and that the growth of a type B crack connecting two facets shields nearby facet regions while amplifying forces farther away.

Load-bearing premise

The idealized facet tip profile $f(y)=\pm\sqrt{1-2y+2y^3-y^4}/2$ and the symmetric equal-spacing arrangement are assumed to represent real echelon cracks, and the conclusion that local binormal shear $F_{BN}$ causes the deviation of $\beta$ from LEFM scaling is drawn without varying the tip shape or comparing against measured propagation directions.

Editorial extensions

If this is right

  • If the central claim holds, planar segments between facets carry a configurational force up to about four times that of the facets, indicating that these planar regions reach the propagation threshold first and so type B cracks form before further facet growth.
  • Facet tilting angle directly sets the driving force magnitude: lower $\varphi$ aligns the facet with the Mode I opening stress, maximizing the configurational force, while the dominant binormal component means facets advance without changing their tilt.
  • The non-zero normal component $F_{CNF,\hat{N}}$ implies that echelon facets can undergo slight rotations in their propagation direction even without in-plane shear, offering a mechanism for the qualitative facet waviness seen in experiments.
  • Facet spacing acts as a control variable: intermediate spacings amplify the driving force through elastic interactions, but below a critical spacing shielding dominates and the force drops, so spacing governs the stability of segmented crack growth.
  • Facet coalescence via a type B crack breaks the symmetry of the force distribution, shielding facet regions near the junction while amplifying more distant regions, which directs subsequent crack growth toward the unshielded parts of the coalescing front.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • We infer that the facet tip profile is not a passive detail: because $F_{BN}$ is invoked as the mechanism, changing the tip shape should measurably change $\beta$ and hence the crack direction, giving a testable knob for steering cracks in soft adhesives and gels.
  • We infer that the amplification-shielding crossover with facet spacing implies a design principle: patterning initial flaws or tuning the mode III fraction could set facet spacing to maximize toughness, since closer spacing first amplifies and then shields the driving force.
  • We infer that applying the same nodal configurational force calculation directly to X-ray tomography meshes of real cracks, rather than idealized geometries, would test the $F_{BN}$ mechanism without the idealization; the paper itself notes this as a future direction.
  • We infer that if the predicted sign reversal of $\beta$ for small facet tilting angles is confirmed experimentally, local-symmetry-type criteria for mixed-mode I+III fracture in soft materials would need a correction term accounting for local binormal shear.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. The paper studies mixed-mode I+III fracture in a soft hydrogel by computing configurational forces with the Configurational Force Method (CFM) implemented as a finite-element post-processor. The authors construct idealized three-dimensional crack geometries—a planar parent crack with tilted finger-like facets, and a variant with a coalesced type B crack—informed by X-ray tomography observations of echelon cracks, and subject these geometries to simulated uniaxial tension followed by torsion. They report how the magnitude and orientation of the computed configurational force per unit crack-front length vary with facet tilt angle, facet spacing, and loading, and they interpret the results as revealing the roles of facet tilting, local binormal shear, facet spacing, and coalescence in determining propagation direction and driving force. The paper explicitly notes that crack propagation is not directly simulated.

Significance. If the central interpretation were fully supported, the work would offer a useful nonlinear, finite-strain alternative to LEFM-based analyses of echelon cracks, with the CFM being generally applicable to arbitrary material behavior and complex crack-front geometry. The paper has clear strengths: the FE and CFM procedures are standard and carefully described, the neo-Hookean material parameters are calibrated against experiments, the mesh-generation pipeline is documented in detail, parameter sweeps over tilt angle and spacing are systematic, and the authors include appendices addressing facet-spacing and finite-size effects on the direction angle β. However, the title-level claim that configurational forces "explain echelon cracks" is not yet supported because the segmented facet geometry is prescribed as an input rather than predicted, and because the mechanistic attribution of the deviations from LEFM scaling to a single local shear component rests on a single hand-chosen tip profile. These are load-bearing gaps, but they are addressable by reframing the claims and by adding targeted numerical tests.

major comments (3)
  1. [§2.2, Appendix B, and title/abstract] The idealized crack geometry is an input, not a prediction: the tilt angle φ, the angular spacing Λ, and the tip profile f(y)=±√(1−2y+2y^3−y^4)/2 are all taken from experimental observations of echelon cracks (Figs. 2a–b, Eq. B.1), and φ is then varied as a parameter. The simulations therefore characterize the configurational forces on an already-segmented front; they do not explain why a planar front segments into tilted facets or why the observed tilt and spacing are selected. Since the paper itself states in §7 that "crack propagation is not directly simulated," and no comparison with measured propagation directions is provided, the title-level claim that the results "explain echelon cracks" overreaches the evidence. The authors should either reframe the claims as a characterization of propagation tendencies of prescribed geometries or add a test that predicts the observed morphology, for example by scanning φ and Λ and showing that the energy-release-rate-maximizing configuration matches the experimental values.
  2. [§4.3, Fig. 5] The central mechanistic claim that local binormal shear F_BN causes the deviation of the force angle β from the LEFM-based scaling is supported only by a single prescribed tip profile and by the observation that the maximum value of F_BN and the angle β both vary with φ and loading. No independent variation of the tip shape is performed: if a different realistic facet profile, such as the circular or elliptical crack approximations used in earlier work [21, 11], changed the F_BN trend or the sign reversal of β for φ≤20°, the explanation would be undermined. In addition, F_BN is a raw component of the deformation gradient, which includes rigid rotation, not a shear strain measure; the claim that it quantifies "shear deformation" should be verified using a frame-invariant measure such as the Green-Lagrange strain component E_BN or a polar-decomposition-based shear angle. I recommend adding a sensitivity study over at least two alternative tip profiles and reporting the corresponding F_BN/E_BN and β trends.
  3. [§4.2, Eqs. (12)–(14), and Appendix D] The attribution of the discrepancy between simulation and LEFM scaling to F_BN is underdetermined. The scaling model neglects non-singular T-stress terms, facet–facet interactions, finite specimen size, and nonlinear material behavior, and Appendix D itself shows a finite-size effect on β for torsion angles α>36°. The observation that β<φ under pure tension and β<0 for φ≤20° under torsion could therefore be caused by any of these omitted effects or by combinations of them. A direct causal test is needed: for example, isolating a single facet in an otherwise identical geometry, or comparing the simulation against an LEFM calculation that includes the T-stress, would help establish that the F_BN contribution—rather than facet interactions or non-singular fields—is the operative mechanism.
minor comments (6)
  1. [Fig. 4 caption] The caption sentence "Angle β ... calculated along the loading of the cylinder in (f)" is unclear; the definition of β and the meaning of panel (f) should be stated explicitly.
  2. [Appendix B, Eq. (B.1)] The construction of the facet profile from f(y)=±√(1−2y+2y^3−y^4)/2 on y∈[−1,0.8] plus the vertical line x=0.8 should be explained more fully: it is not obvious how the coordinates are normalized, why the endpoint is 0.8, and how the resulting width-to-length ratio compares with the experimental facet measurements quoted in §2.1.
  3. [Appendix A] The rheology specimen height is given as 3500 nm (3.5 μm), which appears to be a typo; the intended value is likely 3.5 mm. Please correct the unit.
  4. [§5.1] The legend label "planar" is used both for the facet-free penny-shaped reference crack and for the planar segments of the parent crack; this dual use is confusing and should be disambiguated.
  5. [Appendix D] The paragraph beginning "To assess potential finite-size effects, we repeated the analysis..." is duplicated verbatim; one copy should be removed.
  6. [Data and Software Availability] The statement that data and software "will be available upon reasonable request" is vague for a computational study; depositing the meshes, scripts, and post-processing routines in a public repository would materially improve reproducibility.

Circularity Check

1 steps flagged · score 4.0 of 10

Tilted facets are prescribed input, then read out as the finding that facets maintain their tilt; core force-magnitude results remain independent.

  1. self definitional [Section 2.2 (input geometry) vs Section 4.1 (interpretation of F_CNF,B)]
    "Inspired by experimental geometries reported by Santarossa et al. [53] and Ortellado et al. [21], in the present work, echelon cracks are represented by a central planar region (parent crack), modeled as a thin cylindrical plate with tilted segments (daughter cracks) extending from its edge... Each facet is inclined at a tilting angle ϕ... The profile of each facet is elongated, with a widening tip, resembling the characteristic finger-like shape observed in experiments. ... FCNF, ˆB is the dominant component, whereas FCNF, ˆT remains negligible."

    The facet tilt angle ϕ is prescribed input geometry, taken from the very experimental observations of echelon facets maintaining their orientation. The local B direction is defined in the plane of that prescribed facet (Section 3.4), so the computed dominance of F_CNF,B and the conclusion that 'facets exhibit a propensity to propagate maintaining their tilting angle' restate the imposed facet-plane orientation rather than independently predicting it. Propagation is not simulated and the facet plane cannot evolve, so the maintenance-of-tilt result is the input morphology read back through the chosen local frame.

full rationale

The paper is largely self-contained as a computational study: configurational forces are computed by a standard post-processing method on a neo-Hookean model calibrated to tensile tests (Appendix A), and the magnitude, spacing, and coalescence results are genuine outputs of the FE analysis. The self-citations [21,53] supply experimental morphology, which is external evidence rather than a load-bearing uniqueness theorem. The main circularity is local: echelon tilt is an input, and the statement that facets tend to keep their tilt (Section 4.1) is the same input expressed in the local basis. The F_BN explanation in Section 4.3 is not circular per se, but it is under-tested: F_BN and β are both outputs of one prescribed tip profile, with no tip-shape variation or comparison to measured growth directions, so the causal claim remains a correlation within the model. Overall partial circularity, score 4.

Assumptions & free parameters 4 free parameters · 5 assumptions · 0 invented entities

The central quantitative results depend on the neo-Hookean material parameters (G, ν), the hand-chosen facet shape function, and the idealized symmetric geometry. None of these are fitted to the configurational force outputs, so the force distributions themselves are genuine computations; however, the model geometry is constructed from the very phenomenon being explained, and the LEFM scaling reference is asserted without derivation, which introduces mild circularity into the interpretive step.

free parameters (4)
  • Shear modulus G = 9 kPa
    Calibrated from uniaxial tensile tests of the gelatin hydrogel (Appendix A, Fig. 10A). Sets the stiffness in the neo-Hookean model and affects all computed configurational forces, though it cancels in normalized comparisons.
  • Poisson's ratio ν = 0.451
    Adopted from van Otterloo and Cruden [54] for a 10 wt% gelatin hydrogel. Determines the volumetric response and affects the stress state under constraint.
  • Facet tip profile function f(y) = ±sqrt(1-2y+2y^3-y^4)/2 for y in [-1,0.8]
    Chosen by hand in Appendix B to reproduce the finger-like facet shape observed in experiments. This geometric input directly shapes the local deformation field and the computed F_BN component.
  • Facet tilt angle ϕ and angular spacing Λ = ϕ = 20° and 40°; Λ = 2π/n varied
    Input geometric parameters informed by experimental observations of facet number and tilt angle. The central trends (β versus ϕ; force versus Λ) are parametric studies over these choices, so conclusions depend on these values.
assumptions (5)
  • domain assumption Neo-Hookean hyperelasticity with multiplicative isochoric-volumetric split and Poisson's ratio ν=0.451 adequately represents the 10 wt% gelatin hydrogel under the considered loading conditions.
    Section 3.2 and Appendix A justify this via tensile and rheology tests, but the model remains an idealization; the paper does not validate it under combined tension-torsion at large angles.
  • ad hoc to paper The traction-free idealized crack surface with smooth SDF-based facet integration is a valid model of a real echelon crack system.
    Section 2.2 and Appendix B construct the geometry from experimental images, but the specific shape function and symmetric arrangement are idealizations that may affect the force fields.
  • domain assumption Including spurious nodal configurational forces in the per-unit-length summation improves the approximation of the total configurational force.
    Section 3.4 and reference [60] state this convention; the paper asserts mesh resolution and neighborhood size were selected for stability but does not show a convergence study.
  • standard math The LEFM scaling relations (KI ∼ KI,0 cos²ϕ, KII ∼ KI,0 sinϕ cosϕ, KIII ∼ KIII,0 sin 2ϕ) capture the leading-order stress intensity behavior for an isolated tilted facet.
    Section 4.2 invokes these relations from [62] and [30] as a reference framework; their validity for the simulated geometry is not directly verified.
  • domain assumption The direction of the configurational force vector indicates the preferred crack propagation direction (maximal energy release rate).
    Section 3.4 and Section 7 invoke this standard configurational mechanics interpretation; the paper does not simulate propagation to confirm it for these geometries.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Configurational forces explain echelon cracks in soft materials." pith.science (2026). https://pith.science/paper/KFHGLPEX

@misc{pith2026250712247,
  author       = {Pith},
  title        = {Pith review of: Configurational forces explain echelon cracks in soft materials},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/KFHGLPEX}},
  note         = {Machine review of arXiv:2507.12247}
}
read the original abstract

Soft fracture in highly deformable solids involves both geometric and constitutive nonlinearities, necessitating advanced theoretical and computational frameworks for its accurate understanding. Tensile fractures subjected to mixed-mode loading deviate from their original planar shape, resulting in echelon crack patterns. When out-of-plane shear is superimposed, a crack front segments into an array of tilted facets. The physical interpretation of echelon cracks is only marginally understood, and it is customarily based on rather limited approaches based on Linear Elastic Fracture Mechanics. Here we investigate mixed-mode I + III fracture within the framework of configurational mechanics. Using the Configurational Force Method, implemented as a post-processing algorithm in a finite-element-based simulation, we compute the configurational forces acting at the crack tip of model fracture geometries prior to propagation. Configurational forces characterize both the magnitude and direction of propagation for maximal energy release rate. Our results reveal the complex interactions between tilted facets and their critical role in shaping the fracture morphology. We also examine the effects of facet coalescence-driven by the growth of the parent crack-where neighboring facets merge into a unified crack front. These findings provide new insights into fracture processes in soft, quasi-brittle materials under mixed-mode loading.

Figures

Figures reproduced from arXiv: 2507.12247 by the authors.

Figure 1
Figure 1. Crack front segmentation under mixed-mode I+III loading in a hydrogel. (a) A planar crack is initiated under uniaxial tensile loading (Mode I) and propagates as tension increases. (b) Upon superimposing torsion (Mode III), the initially planar crack front segments into tilted facets. The visible line along the hydrogel surface results from the molding process and is unrelated to the fracture. Schematic insets illust… view at source ↗
Figure 2
Figure 2. Mixed-mode I+III crack morphologies and simplified echelon model representation. Top panel: (a) and (b) show reconstructed echelon crack morphologies from X-ray tomography of cylindrical hydrogel samples fractured under mixed-mode I+III loading. The crack fronts display finger-like facets, curved tips, and type B bridging cracks. Note that samples were imaged under load, resulting in a visually thicker crack surface… view at source ↗
Figure 3
Figure 3. Configurational forces analysis. (a) Idealized geometrical model of a mixed-mode fracture for ϕ = 40°. The rectangles highlight the regions of the crack front where configurational forces are computed: facets and planar segments. (b) Local coordinate frame at points along the crack front within a planar segment. The radial vector is shown for visualization purposes; in practice, the configurational force vector poin… view at source ↗
Figures from the paper (10 more)
Figure 4
Figure 4. Figure 4: Facet tilting angle ϕ controls the direction and strength of the configurational force under mixed-mode loading. The configurational force (CF) is computed by summing individual nodal forces along the facet tip and dividing by the length of the crack tip contour, inclu…
Figure 5
Figure 5. Figure 5: shows the evolution of the maximum value of the deformation gradient component FBN under increasing pure tensile deformation (Mode I phase) for cracks with varying facet tilting angles ϕ. Since FBN varies along the crack front, we compute the maximum value per facet at…
Figure 6
Figure 6. Figure 6: Superimposed torsion reduces the configurational force on planar regions, lowering their growth tendency under mixed-mode loading across different facet tilting angles. (a) Crack mesh with planar segments color-coded by the magnitude of the configurational force, shown…
Figure 7
Figure 7. Figure 7: Facet spacing modulates the configurational force on planar segments. Normalized configurational force magnitude |FCNF|/s on planar crack segments is plotted as a function of facet spacing Λ, for cracks with fixed tilting angle ϕ = 20◦ . The legend “planar” refers to a…
Figure 8
Figure 8. Figure 8: Asymmetric redistribution of configurational forces due to facet coalescence. (a) Schematic of a crack with a nucleated type B crack. Red points indicate mesh nodes where configurational forces are computed. This mesh model was generated using a molecular dynamics-base…
Figure 9
Figure 9. Figure 9: Facet spacing modulates the configurational force at facet edges. Normalized configurational force magnitude |FCNF|/s on facets as a function of facet spacing Λ, for cracks with fixed tilting angles: (a) ϕ = 20◦ and (b) ϕ = 40◦ . As facet spacing decreases, |FCNF|/s in…
Figure 10
Figure 10. Figure 10: Experimental characterization of the gelatin hydrogel. (A) Uniaxial tensile tests. A FE simulation mimicking the experimental samples and loading conditions is used to calibrate the neo-Hookean constitutive model, which will be applied later in this work. (B) Rheologi…
Figure 11
Figure 11. Figure 11: Mesh generation pipeline for the simplified echelon crack geometry. (a) Point cloud defining the facet shape using a mathematical function. (b) Triangulated facet mesh via Delaunay tessellation. (c) Integration of tilted facets into a planar parent crack using smooth …
Figure 12
Figure 12. Figure 12: Mesh processing workflow in the DynaMesh-R pipeline. (i) Initial input mesh with a non-smooth junction between neighboring facets, used as the starting point for the DynaMesh-R routine. (ii) Mesh after molecular dynamics–based relaxation, showing improved regularity a…
Figure 13
Figure 13. Figure 13: a shows the evolution of the angle β—defined between the configurational force vector and the facet plane—throughout the loading path for different facet spacings Λ. During the mode I phase, β remains nearly constant across all values of Λ, with only minimal variation…

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Why planar cracks fragment into echelon cracks

    cond-mat.mtrl-sci 2025-12 conditional novelty 6.0 of 10

    A strength-constrained crack-growth model reproduces echelon crack fragmentation that pure energy minimization cannot.

Reference graph

Works this paper leans on

76 extracted references · 75 canonical work pages · cited by 1 Pith paper

  1. [1]

    Buehler, M. J. & Gao, H. Dynamical fracture instabilities due to local hyperelasticity at crack tips. Nature 439, 307–310 (2006)

  2. [2]

    Dynamic fracture of nominally brittle materials

    Ravi-Chandar, K. Dynamic fracture of nominally brittle materials. International Journal of Fracture 90, 83–102 (1998)

  3. [3]

    P., Marder, M

    Fineberg, J., Gross, S. P., Marder, M. & Swinney, H. L. Instability in dynamic fracture. Physical Review Letters 67, 457–460 (1991)

  4. [4]

    & Fineberg, J

    Kolvin, I., Cohen, G. & Fineberg, J. Crack front dynamics: The interplay of singular geometry and crack instabilities. Physical Review Letters 114, 175501 (2015)

  5. [5]

    G., Cohen, G

    Boué, T. G., Cohen, G. & Fineberg, J. Origin of the microbranching instability in rapid cracks. Physical Review Letters 114, 054301 (2015)

  6. [6]

    Wu, K. et al. Distorting crack-front geometry for enhanced toughness by manipulating bioinspired heterogeneity. Nature Communications 16, 1–13 (2025)

  7. [7]

    & Rubinstein, S

    Steinhardt, W. & Rubinstein, S. M. How material heterogeneity creates rough fractures. Physical Review Letters 129, 128001 (2022)

  8. [8]

    & Rubinstein, S

    Steinhardt, W. & Rubinstein, S. M. Geometric rules for the annihilation dynamics of step lines on fracture fronts. Physical Review E 107, 055003 (2023)

Show all 76 references
  1. [9]

    & Adda-Bedia, M

    Lechenault, F., Sapoval, B. & Adda-Bedia, M. Morphology and dynamics of a crack front propagating in a model disordered material. Journal of the Mechanics and Physics of Solids 74, 38–48 (2015)

  2. [10]

    & Fisher, D

    Ramanathan, S. & Fisher, D. S. Quasistatic crack propagation in heterogeneous media. Physical Review Letters 79, 873–876 (1997)

  3. [11]

    Pham, K. H. & Ravi-Chandar, K. On the growth of cracks under mixed-mode i + iii loading.International Journal of Fracture 199, 105–134 (2016)

  4. [12]

    & Baumberger, T

    Ronsin, O., Caroli, C. & Baumberger, T. Crack front échelon instability in mixed mode fracture of a strongly nonlinear elastic solid. Europhysics Letters 105, 34001 (2014). 29 A PREPRINT - S EPTEMBER 24, 2025

  5. [13]

    Goldstein, R. V . & Osipenko, N. M. Fracture structure near a longitudinal shear macrorupture. Mechanics of Solids 47, 565–574 (2012)

  6. [14]

    Goldstein, R. V . & Osipenko, N. M. Development of multiple ordered fracture in an elastic homogeneous, structured and layered medium. Fatigue & Fracture of Engineering Materials & Structures37, 1292–1305 (2014)

  7. [15]

    D., Segall, P

    Pollard, D. D., Segall, P. & Delaney, P. T. Formation and interpretation of dilatant echelon cracks.GSA Bulletin 93, 1291–1303 (1982)

  8. [16]

    Formation of fracture ‘lances’ in glass

    Sommer, E. Formation of fracture ‘lances’ in glass. Engineering Fracture Mechanics 1, 539–546 (1969)

  9. [17]

    & Wiebesiek, J

    Lazarus, V ., Buchholz, F.-G., Fulland, M. & Wiebesiek, J. Comparison of predictions by mode ii or mode iii criteria on crack front twisting in three or four point bending experiments. International Journal of Fracture 153, 141–151 (2008)

  10. [18]

    Lin, B., Mear, M. E. & Ravi-Chandar, K. Criterion for initiation of cracks under mixed-mode i + iii loading. International Journal of Fracture165, 175–188 (2010)

  11. [19]

    Pham, K. H. & Ravi-Chandar, K. Further examination of the criterion for crack initiation under mixed-mode i+iii loading. International Journal of Fracture189, 121–138 (2014)

  12. [20]

    Some Fundamental Mechanisms of Hydraulic Fracturing

    Wu, R. Some Fundamental Mechanisms of Hydraulic Fracturing. Doctoral dissertation, Georgia Institute of Technology (2006)

  13. [21]

    Ortellado, L., Abate, A., Santarossa, A., Gómez, L. R. & Pöschel, T. Principle of local symmetry in mixed-mode fracture. Communications Physics 8, 1–11 (2025)

  14. [22]

    & Lazarus, V

    Leblond, J.-B., Karma, A. & Lazarus, V . Theoretical analysis of crack front instability in mode i+iii.Journal of the Mechanics and Physics of Solids 59, 1872–1887 (2011)

  15. [23]

    & Lazarus, V

    Cambonie, T. & Lazarus, V . Quantification of the crack fragmentation resulting from mode i+iii loading.Procedia Materials Science 3, 1816–1821 (2014). 20th European Conference on Fracture

  16. [24]

    V .Deciphering triangular fracture patterns in PMMA: how crack fragments in mixed mode loading

    Vasudevan, A. V .Deciphering triangular fracture patterns in PMMA: how crack fragments in mixed mode loading. Ph.d. thesis, Sorbonne Université (2018)

  17. [25]

    & Ponson, L

    Lebihain, M., Leblond, J.-B. & Ponson, L. Crack front instability in mixed-mode i+iii: The influence of non-singular stresses. European Journal of Mechanics - A/Solids 100, 104602 (2022)

  18. [26]

    & Leblond, J.-B

    Vasudevan, A., Ponson, L., Karma, A. & Leblond, J.-B. Configurational stability of a crack propagating in a material with mode-dependent fracture energy – part ii: Drift of fracture facets in mixed-mode i+ii+iii. Journal of the Mechanics and Physics of Solids 137, 103894 (2020)

  19. [27]

    & Vasudevan, A

    Leblond, J.-B., Karma, A., Ponson, L. & Vasudevan, A. Configurational stability of a crack propagating in a material with mode-dependent fracture energy - part i: Mixed-mode i+iii. Journal of the Mechanics and Physics of Solids 126, 187–203 (2019). 30 A PREPRINT - S EPTEMBER 24, 2025

  20. [28]

    Bahmani, A. et al. On the comparison of two mixed-mode i + iii fracture test specimens. Engineering Fracture Mechanics 241, 107434 (2021)

  21. [29]

    Hodgdon, J. A. & Sethna, J. P. Derivation of a general three-dimensional crack-propagation law: A generalization of the principle of local symmetry. Physical Review B 47, 4831–4840 (1993)

  22. [30]

    & Lazarus, V

    Molnár, G., Doitrand, A. & Lazarus, V . Phase-field simulation and coupled criterion link echelon cracks to internal length in antiplane shear. Journal of the Mechanics and Physics of Solids 188, 105675 (2024)

  23. [31]

    & Fineberg, J

    Bouchbinder, E., Livne, A. & Fineberg, J. The 1/r singularity in weakly nonlinear fracture mechanics. Journal of the Mechanics and Physics of Solids 57, 1568 (2009)

  24. [32]

    & Fineberg, J

    Bouchbinder, E., Livne, A. & Fineberg, J. Weakly nonlinear fracture mechanics: experiments and theory. International Journal of Fracture161, 1–20 (2009)

  25. [33]

    & Fineberg, J

    Bouchbinder, E., Livne, A. & Fineberg, J. Weakly nonlinear theory of dynamic fracture. Physical Review Letters 101, 264302 (2008)

  26. [34]

    G., Harpaz, R., Fineberg, J

    Boué, T. G., Harpaz, R., Fineberg, J. & Bouchbinder, E. Failing softly: a fracture theory of highly-deformable materials. Soft Matter 11, 3812–3821 (2015)

  27. [35]

    & Fineberg, J

    Livne, A., Bouchbinder, E. & Fineberg, J. The near-tip fields of fast cracks. Science 327, 1359–1363 (2010)

  28. [36]

    & Fineberg, J

    Livne, A., Bouchbinder, E. & Fineberg, J. Breakdown of linear elastic fracture mechanics near the tip of a rapid crack. Physical Review Letters 101, 264301 (2008)

  29. [37]

    & Kolinski, J

    Wei, X., Li, C., McCarthy, C. & Kolinski, J. M. Complexity of crack front geometry enhances toughness of brittle solids. Nature Physics 20, 1009–1014 (2024)

  30. [38]

    Pons, A. J. & Karma, A. Helical crack-front instability in mixed-mode fracture. Nature 2010 464:7285 464, 85–89 (2010)

  31. [39]

    Chen, C.-H. et al. Crack front segmentation and facet coarsening in mixed-mode fracture. Phys. Rev. Lett. 115, 265503 (2015)

  32. [40]

    Crack front instabilities under mixed mode loading in three dimensions

    Henry, H. Crack front instabilities under mixed mode loading in three dimensions. Europhysics Letters 114, 66001 (2016)

  33. [41]

    & Karma, A

    Leblond, J.-B., Lazarus, V . & Karma, A. Multiscale cohesive zone model for propagation of segmented crack fronts in mode i+ iii fracture. International Journal of Fracture191, 167–189 (2015)

  34. [42]

    & Leblond, J

    Lazarus, V ., Prabel, B., Cambonie, T. & Leblond, J. Mode i+ iii multiscale cohesive zone model with facet coarsening and overlap: Solutions and applications to facet orientation and toughening. Journal of the Mechanics and Physics of Solids 141, 104007 (2020)

  35. [43]

    & Lazarus, V

    Hattali, M., Cambonie, T. & Lazarus, V . Toughening induced by the formation of facets in mode i+ iii brittle fracture: experiments versus a two-scale cohesive zone model. Journal of the Mechanics and Physics of Solids 156, 104596 (2021). 31 A PREPRINT - S EPTEMBER 24, 2025

  36. [44]

    & Ortiz, M

    Pandolfi, A. & Ortiz, M. An eigenerosion approach to brittle fracture. International Journal for Numerical Methods in Engineering 92, 694–714 (2012)

  37. [45]

    Cherepanov, G. P. Crack propagation in continuous media. Journal of Applied Mathematics and Mechanics 31, 503–512 (1967)

  38. [46]

    Rice, J. R. A path independent integral and the approximate analysis of strain concentration by notches and cracks. Journal of Applied Mechanics 35, 379 (1968)

  39. [47]

    & Ricoeur, A

    Schmitz, K. & Ricoeur, A. Theoretical and computational aspects of configurational forces in three-dimensional crack problems. International Journal of Solids and Structures 282, 112456 (2023)

  40. [48]

    Moreno-Mateos, M. A. & Steinmann, P. Configurational force method enables fracture assessment in soft materials. Journal of the Mechanics and Physics of Solids 186, 105602 (2024)

  41. [49]

    Serrao, P. H. & Kozinov, S. Evaluation of configurational/material forces in strain gradient elasticity theory. Mechanics of Materials 203, 105240 (2025)

  42. [50]

    Goda, I., Ganghoffer, J. F. & Maurice, G. Combined bone internal and external remodeling based on eshelby stress. International Journal of Solids and Structures 94-95, 138–157 (2016)

  43. [51]

    Configurational forces induced by finite-element discretization

    Braun, M. Configurational forces induced by finite-element discretization. Proceedings of the Estonian Academy of Sciences : Physics, Mathematics 46, 24–31 (1997)

  44. [52]

    & Mouchrif, S.-E

    Lazarus, V ., Leblond, J.-B. & Mouchrif, S.-E. Crack front rotation and segmentation in mixed mode i+iii or i+ii+iii. part i: Calculation of stress intensity factors. Journal of the Mechanics and Physics of Solids 49, 1399–1420 (2001)

  45. [53]

    Santarossa, A., Ortellado, L., Sack, A., Gómez, L. R. & Pöschel, T. A device for studying fluid-induced cracks under mixed-mode loading conditions using x-ray tomography. Review of Scientific Instruments 94 (2023)

  46. [54]

    & Cruden, A

    van Otterloo, J. & Cruden, A. R. Rheology of pig skin gelatine: Defining the elastic domain and its thermal and mechanical properties for geological analogue experiment applications. Tectonophysics 683, 86–97 (2016)

  47. [55]

    Eshelby, J. D. The force on an elastic singularity. Philosophical Transactions of the Royal Society of London 244 (1951)

  48. [56]

    & Herrmann, G

    Kienzler, R. & Herrmann, G. On the properties of the eshelby tensor. Acta Mechanica 125, 73–91 (1997)

  49. [57]

    Eshelby, J. D. The elastic energy-momentum tensor. Journal of Elasticity 5, 321–335 (1975)

  50. [58]

    Eshelby, J. D. Energy relations and the energy-momentum tensor in continuum mechanics. Fundamental Contributions to the Continuum Theory of Evolving Phase Interfaces in Solids 82–119 (1999)

  51. [59]

    & Barth, F

    Steinmann, P., Ackermann, D. & Barth, F. Application of material forces to hyperelastostatic fracture mechanics. ii. computational setting. International Journal of Solids and Structures 38, 5509–5526 (2001)

  52. [60]

    Denzer, R., Barth, F. J. & Steinmann, P. Studies in elastic fracture mechanics based on the material force method. International Journal for Numerical Methods in Engineering 58, 1817–1835 (2003). 32 A PREPRINT - S EPTEMBER 24, 2025

  53. [61]

    & Wells, G

    Logg, A., Mardal, K.-A. & Wells, G. Automated Solution of Differential Equations by the Finite Element Method, vol. 84 (Springer Berlin Heidelberg, 2012)

  54. [62]

    Analysis of stress intensity factors of modes i, ii and iii for inclined surface cracks of arbitrary shape

    Murakami, Y . Analysis of stress intensity factors of modes i, ii and iii for inclined surface cracks of arbitrary shape. Engineering Fracture Mechanics 22, 101–114 (1985)

  55. [63]

    & Rice, J

    Cotterell, B. & Rice, J. R. Slightly curved or kinked cracks. International journal of fracture 16, 155–169 (1980)

  56. [64]

    N., Paluszny, A

    Thomas, R. N., Paluszny, A. & Zimmerman, R. W. Quantification of fracture interaction using stress intensity factor variation maps. Journal of Geophysical Research: Solid Earth 122, 7698–7717 (2017)

  57. [65]

    & Needleman, A

    Li, F., Shih, C. & Needleman, A. A comparison of methods for calculating energy release rates. Engineering Fracture Mechanics 21, 405–421 (1985)

  58. [66]

    A., Wiesheier, S., Esmaeili, A., Hossain, M

    Moreno-Mateos, M. A., Wiesheier, S., Esmaeili, A., Hossain, M. & Steinmann, P. Biaxial characterization of soft elastomers: experiments and data-adaptive configurational forces for fracture (2025). 2505.20244

  59. [67]

    Bishara, D. & Li, S. A material energy–momentum flux-driven phase field fracture mechanics model. Computer Methods in Applied Mechanics and Engineering 425, 116920 (2024)

  60. [68]

    A., Mehnert, M

    Moreno-Mateos, M. A., Mehnert, M. & Steinmann, P. Electro-mechanical actuation modulates fracture perfor- mance of soft dielectric elastomers. International Journal of Engineering Science 195, 104008 (2024)

  61. [69]

    & Javili, A

    Steinmann, P., de Villiers, A., McBride, A. & Javili, A. Configurational peridynamics. Mechanics of Materials 185, 104751 (2023)

  62. [70]

    & Sramek, M

    Jones, M., Baerentzen, J. & Sramek, M. 3d distance fields: a survey of techniques and applications. IEEE Transactions on Visualization and Computer Graphics12, 581–599 (2006)

  63. [71]

    & Müller, H

    V ollmer, J., Mencl, R. & Müller, H. Improved laplacian smoothing of noisy surface meshes.Computer Graphics Forum 18, 131–138 (1999)

  64. [72]

    & Cignoni, P

    Muntoni, A. & Cignoni, P. PyMeshLab (2021)

  65. [73]

    A lightweight approach to repairing digitized polygon meshes

    Attene, M. A lightweight approach to repairing digitized polygon meshes. The Visual Computer 26, 1393–1406 (2010)

  66. [74]

    A., Lorenz, C

    Anderson, J. A., Lorenz, C. D. & Travesset, A. General purpose molecular dynamics simulations fully implemented on graphics processing units. Journal of Computational Physics 227, 5342–5359 (2008)

  67. [75]

    Glaser, J. et al. Strong scaling of general-purpose molecular dynamics simulations on gpus. Computer Physics Communications 192, 97–107 (2015)

  68. [76]

    & Parrinello, M

    Bussi, G., Donadio, D. & Parrinello, M. Canonical sampling through velocity rescaling. The Journal of Chemical Physics 126, 014101 (2007). 33

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.