pith. sign in

arxiv: 2604.07025 · v1 · submitted 2026-04-08 · 🧮 math.DS · cs.LG· cs.NA· math.NA

Physics-Informed Functional Link Constrained Framework with Domain Mapping for Solving Bending Analysis of an Exponentially Loaded Perforated Beam

Pith reviewed 2026-05-10 17:56 UTC · model grok-4.3

classification 🧮 math.DS cs.LGcs.NAmath.NA
keywords perforated beambending analysisexponential loadtheory of functional connectionsfunctional link neural networkphysics-informed neural networksdomain mappingtapered beam
0
0 comments X

The pith

A domain-mapped functional link method solves perforated beam bending more accurately and with lower cost than PINN.

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

This paper develops the DFL-TFC framework to compute the deflection of a tapered beam with square holes under an exponentially varying distributed load. The governing differential equation directly includes the filling ratio, number of hole rows, two tapering parameters, and the exponential load decay rate. The method maps the physical interval to the domain of chosen orthogonal polynomials, forms a constrained expression that satisfies the boundary conditions exactly through the Theory of Functional Connections, and approximates the remaining free function with a functional link network whose expansion uses polynomial basis functions. Side-by-side tests against a physics-informed neural network formulation show faster convergence, lower computational cost, and smaller pointwise errors for the same physical parameters. Readers working on lightweight structural design would care because the approach supplies an exact-constraint alternative to penalty-based or mesh-based solvers for this class of variable-coefficient beam problems.

Core claim

The DFL-TFC framework replaces the hidden layer with a functional expansion block using orthogonal polynomial basis functions, maps the differential equation domain to the corresponding polynomial domain, constructs a constrained expression via the Theory of Functional Connections so that boundary conditions are satisfied exactly, and lets a Functional Link Neural Network learn the free function that solves the resulting unconstrained problem; the resulting solutions for the perforated beam deflection are more accurate, converge faster, and require less computation than those obtained from a comparable PINN formulation, with further agreement against independent Galerkin solutions.

What carries the argument

The DFL-TFC framework, which maps the physical domain to the orthogonal polynomial domain, replaces the neural hidden layer with a functional expansion block, and enforces boundary conditions exactly through a Theory of Functional Connections constrained expression whose free function is represented by a Functional Link Neural Network.

If this is right

  • Boundary conditions are satisfied exactly by construction, eliminating the need for penalty terms in the loss function.
  • The same framework applies without reformulation to any combination of the parameters α, N, φ, ψ, and γ.
  • Computational cost is lower than PINN while error norms are also smaller.
  • Results remain consistent with independent Galerkin solutions across the tested configurations.
  • The method extends naturally to other ordinary differential equations that arise in tapered or perforated structural members.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Domain mapping combined with exact-constraint functional expressions may reduce the depth or width needed for neural solvers on other variable-coefficient beam or plate problems.
  • If the improvement is driven by the polynomial expansion rather than the network itself, swapping different orthogonal bases could further tune accuracy for extreme taper values.
  • The approach supplies a concrete test case for whether functional-link methods systematically outperform standard PINNs on problems whose coefficients vary smoothly but whose geometry is piecewise.

Load-bearing premise

The specific choices of orthogonal polynomial basis, domain mapping, and network architecture produce a solution whose error is uniformly smaller than PINN across the full range of physical parameters without hidden fitting or selective reporting.

What would settle it

A side-by-side run of DFL-TFC and PINN on identical parameter sets for filling ratio, hole rows, taper rates, and load exponent, trained to the same tolerance, followed by direct comparison of maximum absolute deflection error against a high-resolution Galerkin reference solution.

Figures

Figures reproduced from arXiv: 2604.07025 by Iswari Sahu, Ramanath Garai, S. Chakraverty.

Figure 1
Figure 1. Figure 1: Geometric model of a tapered perforated beam [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Schematic diagram of PINN 4.2 Galerkin Approximation Procedure The transverse displacement of the perforated tapered beam, denoted by Wp(X), is approx￾imated using a finite series of basis functions as [26, 21]: W p(X) = Xn i=1 ηiΘi(X), (14) where n is number of basis functions, ηi are unknown coefficients, and Θi(X) represent orthonormal polynomial functions, which comes from simple polynomial Xi−1 , i = … view at source ↗
Figure 3
Figure 3. Figure 3: Schematic diagram of Domain mapped FL-TFC [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: DFL-TFC and PINN solution for α = 0.8, γ = 5, ϕ = 0.5, ψ = 0.5, N = 3, Kfp = 10, qe0 = 1 5.2 New Outcomes The bending deflection of a tapered perforated beam is obtained using the DFL-TFC method, which demonstrates faster convergence, higher accuracy, and greater computational efficiency compared with the traditional physics-informed neural network (PINN) approach [PITH_FULL_IMAGE:figures/full_fig_p014_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Variation of bending deflection with respect to filling ratio [PITH_FULL_IMAGE:figures/full_fig_p018_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Variation of bending deflection with respect to exponential load parameter [PITH_FULL_IMAGE:figures/full_fig_p018_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Effect of tapering parameter ϕ on the bending behaviour of a tapered perforated beam resting on a foundation 19 [PITH_FULL_IMAGE:figures/full_fig_p019_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Effect of tapering parameter ψ on the bending behaviour of a tapered perforated beam resting on a foundation 5.2.4 Effect of foundation parameter It is important to mention that the foundation parameter Kfp strongly influences the bending deflection of the tapered perforated beam. The effect of this foundation parameter Kfp is presented in [PITH_FULL_IMAGE:figures/full_fig_p020_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Effect of elastic foundation parameter Kfp on the bending behaviour of a tapered perforated beam with exponential load 20 [PITH_FULL_IMAGE:figures/full_fig_p020_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Loss figures of PINN and DFL-TFC frameworks at different parameters for S-S [PITH_FULL_IMAGE:figures/full_fig_p022_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: Loss figures of PINN and DFL-TFC frameworks at different parameters for C-S [PITH_FULL_IMAGE:figures/full_fig_p023_11.png] view at source ↗
read the original abstract

This article presents a novel and comprehensive approach for analyzing bending behavior of the tapered perforated beam under an exponential load. The governing differential equation includes important factors like filling ratio ($\alpha$), number of rows of holes ($N$), tapering parameters ($\phi$ and $\psi$), and exponential loading parameter ($\gamma$), providing a realistic and flexible representation of perforated beam configuration. Main goal of this work is to see how well the Domain mapped physics-informed Functional link Theory of Functional Connection (DFL-TFC) method analyses bending response of perforated beam with square holes under exponential loading. For comparison purposes, a corresponding PINN-based formulation is developed. Outcomes clearly show that the proposed DFL-TFC framework gives better results, including faster convergence, reduced computational cost, and improved solution accuracy when compared to the PINN approach. These findings highlight effectiveness and potential of DFL-TFC method for solving complex engineering problems governed by differential equations. Within this framework, hidden layer is replaced by a functional expansion block that enriches input representation via orthogonal polynomial basis functions, and the domain of DE mapped to corresponding domain of orthogonal polynomials. A Constrained Expression (CE), constructed through the Theory of Functional Connections (TFC) using boundary conditions, ensures that constraints are exactly satisfied. In CE, free function is represented using a Functional Link Neural Network (FLNN), which learns to solve resulting unconstrained optimization problem. The obtained results are further validated through the Galerkin and PINN solutions.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript introduces the Domain-mapped physics-informed Functional Link Constrained Framework (DFL-TFC) for analyzing the bending of a tapered perforated beam under exponential load. The governing DE incorporates parameters including filling ratio α, number of hole rows N, tapering parameters φ and ψ, and exponential load parameter γ. The method replaces the hidden layer with a functional expansion using orthogonal polynomial basis functions, maps the physical domain to the polynomial interval, employs the Theory of Functional Connections (TFC) to build a constrained expression that exactly satisfies boundary conditions, and uses a Functional Link Neural Network (FLNN) as the free function to solve the resulting unconstrained problem. Numerical outcomes are compared to a corresponding PINN formulation and Galerkin method, with the claim of faster convergence, lower computational cost, and higher accuracy for DFL-TFC.

Significance. If the performance advantages are substantiated with quantitative evidence across the parameter space, the combination of domain mapping, orthogonal polynomial enrichment, and exact TFC constraint satisfaction could provide an efficient alternative to standard PINNs for constrained differential equations in structural mechanics. The low number of free parameters in the FLNN component is a methodological strength that merits careful validation.

major comments (2)
  1. Abstract: The assertion that 'outcomes clearly show that the proposed DFL-TFC framework gives better results, including faster convergence, reduced computational cost, and improved solution accuracy when compared to the PINN approach' is unsupported by any quantitative metrics such as L2 or maximum error norms, iteration counts, wall-clock times, or convergence plots for varying values of α, N, φ, ψ, and γ.
  2. Numerical results section: No tables or figures report error norms, computational costs, or performance metrics across the full range of physical parameters (α, N, φ, ψ, γ), making it impossible to verify the central claim of uniform superiority or to rule out selective reporting or problem-specific hyperparameter tuning.
minor comments (2)
  1. The specific choice of orthogonal polynomial family (Legendre, Chebyshev, etc.) and the explicit form of the domain mapping function should be stated with equations in the method section.
  2. A schematic figure of the tapered perforated beam geometry with square holes and the applied exponential load would clarify the physical setup and parameter definitions.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the thorough review and valuable comments on our manuscript. The feedback correctly identifies the need for stronger quantitative evidence to support the performance claims of the DFL-TFC framework relative to PINN. We will revise the manuscript to incorporate the requested metrics and comparisons across the parameter space.

read point-by-point responses
  1. Referee: Abstract: The assertion that 'outcomes clearly show that the proposed DFL-TFC framework gives better results, including faster convergence, reduced computational cost, and improved solution accuracy when compared to the PINN approach' is unsupported by any quantitative metrics such as L2 or maximum error norms, iteration counts, wall-clock times, or convergence plots for varying values of α, N, φ, ψ, and γ.

    Authors: We agree that the abstract claim requires explicit quantitative backing. In the revised manuscript we will modify the abstract to reference specific supporting metrics and ensure the numerical section provides L2 and maximum error norms, iteration counts, wall-clock times, and convergence plots for representative values of α, N, φ, ψ, and γ. These additions will directly substantiate the stated advantages. revision: yes

  2. Referee: Numerical results section: No tables or figures report error norms, computational costs, or performance metrics across the full range of physical parameters (α, N, φ, ψ, γ), making it impossible to verify the central claim of uniform superiority or to rule out selective reporting or problem-specific hyperparameter tuning.

    Authors: We acknowledge that the current numerical results section lacks comprehensive error norms and performance metrics over the full parameter range. The revised version will include new tables and figures reporting L2 and maximum errors, iteration counts, and wall-clock times for multiple combinations of α, N, φ, ψ, and γ. This will enable verification of performance across the space and address concerns regarding selective reporting. revision: yes

Circularity Check

0 steps flagged

No significant circularity in derivation or performance claims

full rationale

The paper presents a numerical solver (DFL-TFC) that maps the domain, uses orthogonal polynomial expansion inside a TFC-constrained expression whose free function is an FLNN, and minimizes the DE residual. This construction directly implements the standard physics-informed collocation approach and is compared to independent external methods (Galerkin and a separately formulated PINN). No equation or claim reduces the obtained solution, error norms, convergence rate, or computational cost to the input parameters or basis choices by definition. Validation against Galerkin and PINN supplies external benchmarks rather than self-referential fitting. The performance superiority statement is therefore an empirical outcome of the experiments, not a tautology.

Axiom & Free-Parameter Ledger

4 free parameters · 2 axioms · 0 invented entities

The framework rests on standard properties of orthogonal polynomials, the existence of a TFC constrained expression for the chosen boundary conditions, and the assumption that the functional-link network can represent the residual-minimizing function. No new physical entities are postulated.

free parameters (4)
  • filling ratio alpha
    Physical parameter controlling hole size fraction; appears in the governing DE and is varied in experiments.
  • number of hole rows N
    Discrete parameter defining perforation pattern; enters the DE coefficients.
  • tapering parameters phi and psi
    Coefficients controlling linear taper in beam height and width.
  • exponential load parameter gamma
    Controls the spatial decay rate of the applied load.
axioms (2)
  • standard math Orthogonal polynomials form a complete basis on the mapped domain.
    Invoked when replacing the hidden layer with functional expansion.
  • domain assumption The TFC constrained expression exactly satisfies the boundary conditions for any choice of the free function.
    Central to the method; stated in the description of the constrained expression.

pith-pipeline@v0.9.0 · 5588 in / 1574 out tokens · 35066 ms · 2026-05-10T17:56:24.531624+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Forward citations

Cited by 1 Pith paper

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

  1. Comparative Study of Bending Analysis using Physics-Informed Neural Networks and Numerical Dynamic Deflection in Perforated nanobeam

    cs.LG 2026-04 unverdicted novelty 5.0

    A domain-mapped functional link neural network solves static bending of perforated nanobeams and is compared to Galerkin results for dynamic deflection.

Reference graph

Works this paper leans on

32 extracted references · 32 canonical work pages · cited by 1 Pith paper · 1 internal anchor

  1. [1]

    O. C. Zienkiewicz, R. L. Taylor, P. Nithiarasu, and J. Zhu,The finite element method, vol. 3. Elsevier, 1977

  2. [2]

    Finite difference method for numerical computation of discontinuous solutions of the equations of fluid dynamics,

    S. K. Godunov and I. Bohachevsky, “Finite difference method for numerical computation of discontinuous solutions of the equations of fluid dynamics,”Matematiˇ ceskij sbornik, vol. 47, no. 3, pp. 271–306, 1959

  3. [3]

    Physics-informed neural networks: A deep learning framework for solving forward and inverse problems involving nonlinear partial differential equations,

    M. Raissi, P. Perdikaris, and G. E. Karniadakis, “Physics-informed neural networks: A deep learning framework for solving forward and inverse problems involving nonlinear partial differential equations,”Journal of Computational physics, vol. 378, pp. 686–707, 2019

  4. [4]

    Scientific machine learning through physics–informed neural networks: Where we are and what’s next,

    S. Cuomo, V. S. Di Cola, F. Giampaolo, G. Rozza, M. Raissi, and F. Piccialli, “Scientific machine learning through physics–informed neural networks: Where we are and what’s next,”Journal of Scientific Computing, vol. 92, no. 3, p. 88, 2022

  5. [5]

    Three ways to solve partial differential equations with neural networks—a review,

    J. Blechschmidt and O. G. Ernst, “Three ways to solve partial differential equations with neural networks—a review,”Gamm-mitteilungen, vol. 44, no. 2, p. e202100006, 2021

  6. [6]

    A simple analytical model for the resonance frequency of per- forated beams,

    L. Luschi and F. Pieri, “A simple analytical model for the resonance frequency of per- forated beams,”Procedia Engineering, vol. 47, pp. 1093–1096, 2012

  7. [7]

    An analytical model for the determination of resonance frequen- cies of perforated beams,

    L. Luschi and F. Pieri, “An analytical model for the determination of resonance frequen- cies of perforated beams,”Journal of Micromechanics and Microengineering, vol. 24, no. 5, p. 055004, 2014. 26

  8. [8]

    Physics-informed neural network for bending and free vibration analysis of three-dimensional functionally graded porous beam resting on elas- tic foundation,

    A. Fallah and M. M. Aghdam, “Physics-informed neural network for bending and free vibration analysis of three-dimensional functionally graded porous beam resting on elas- tic foundation,”Engineering with Computers, vol. 40, no. 1, pp. 437–454, 2024

  9. [9]

    Kianian, S

    O. Kianian, S. Sarrami, B. Movahedian, and M. Azhari, “Pinn-based forward and in- verse bending analysis of nanobeams on a three-parameter nonlinear elastic foundation including hardening and softening effect using nonlocal elasticity theory,”Engineering with Computers, vol. 41, no. 1, pp. 71–97, 2025

  10. [10]

    Second-order analysis of beam- columns by machine learning-based structural analysis through physics-informed neural networks,

    L. Chen, H.-Y. Zhang, S.-W. Liu, and S.-L. Chan, “Second-order analysis of beam- columns by machine learning-based structural analysis through physics-informed neural networks,”Advanced Steel Construction, vol. 19, no. 4, pp. 411–420, 2023

  11. [11]

    Application of physics-informed neural networks for nonlinear buckling analysis of beams,

    M. Bazmara, M. Mianroodi, and M. Silani, “Application of physics-informed neural networks for nonlinear buckling analysis of beams,”Acta Mechanica Sinica, vol. 39, no. 6, p. 422438, 2023

  12. [12]

    A physics-informed neural networks framework for model parameter iden- tification of beam-like structures,

    R. d. O. Teloli, R. Tittarelli, M. Bigot, L. Coelho, E. Ramasso, P. Le Moal, and M. Ouisse, “A physics-informed neural networks framework for model parameter iden- tification of beam-like structures,”Mechanical Systems and Signal Processing, vol. 224, p. 112189, 2025

  13. [13]

    Transfer learning for improved generalizability in causal physics-informed neural networks for beam simulations,

    T. Kapoor, H. Wang, A. N´ u˜ nez, and R. Dollevoet, “Transfer learning for improved generalizability in causal physics-informed neural networks for beam simulations,”En- gineering Applications of Artificial Intelligence, vol. 133, p. 108085, 2024

  14. [14]

    When and why pinns fail to train: A neural tangent kernel perspective,

    S. Wang, X. Yu, and P. Perdikaris, “When and why pinns fail to train: A neural tangent kernel perspective,”Journal of Computational Physics, vol. 449, p. 110768, 2022

  15. [15]

    Character- izing possible failure modes in physics-informed neural networks,

    A. Krishnapriyan, A. Gholami, S. Zhe, R. Kirby, and M. W. Mahoney, “Character- izing possible failure modes in physics-informed neural networks,”Advances in neural information processing systems, vol. 34, pp. 26548–26560, 2021

  16. [16]

    Resonance frequencies of size depen- dent perforated nonlocal nanobeam,

    M. Eltaher, A. Abdraboh, and K. Almitani, “Resonance frequencies of size depen- dent perforated nonlocal nanobeam,”Microsystem Technologies, vol. 24, pp. 3925–3937, 2018

  17. [17]

    Size-dependent dynamics of perforated and short-fiber-reinforced nanowires based on non-local modified couple stress theory,

    M. Akpınar, B. Uzun, and M. ¨O. Yaylı, “Size-dependent dynamics of perforated and short-fiber-reinforced nanowires based on non-local modified couple stress theory,”Jour- nal of Vibration Engineering & Technologies, vol. 13, no. 3, p. 208, 2025

  18. [18]

    Influence of flexoelectricity on bending of piezoelectric perforated fg composite nanobeam rested on elastic foundation,

    A. Alnujaie, A. A. Abdelrahman, A. M. Alanasari, and M. A. Eltaher, “Influence of flexoelectricity on bending of piezoelectric perforated fg composite nanobeam rested on elastic foundation,”Steel and Composite Structures, vol. 49, no. 4, pp. 361–380, 2023

  19. [19]

    Dynamics of perforated higher order nanobeams subject to moving load using the nonlocal strain gradient theory,

    A. A. Abdelrahman, I. Esen, C. Ozarpa, R. Shaltout, M. A. Eltaher, and A. E. Assie, “Dynamics of perforated higher order nanobeams subject to moving load using the nonlocal strain gradient theory,”Smart Struct. Syst, vol. 28, no. 4, pp. 515–533, 2021. 27

  20. [20]

    Size-dependent bending response of perforated nanobeams on winkler- pasternak foundation,

    U. Kafkas, “Size-dependent bending response of perforated nanobeams on winkler- pasternak foundation,”International Journal of Engineering and Applied Sciences, vol. 17, no. 1, pp. 1–16, 2025

  21. [21]

    Effect of axial functional gradation and periodic square perforations on the vibration of nanobeams with elastic foundation,

    R. Garai, A. K. Gartia, and S. Chakraverty, “Effect of axial functional gradation and periodic square perforations on the vibration of nanobeams with elastic foundation,” International Journal of Structural Stability and Dynamics, p. 2750188, 2026

  22. [22]

    Physics-informed machine learning frame- work for approximating the modified degasperis-procesi equation,

    S. Kumar, A. K. Sahoo, and S. Chakraverty, “Physics-informed machine learning frame- work for approximating the modified degasperis-procesi equation,” in2023 International Conference on Ambient Intelligence, Knowledge Informatics and Industrial Electronics (AIKIIE), pp. 1–6, IEEE, 2023

  23. [23]

    Automatic differentiation in pytorch,

    A. Paszke, S. Gross, S. Chintala, G. Chanan, E. Yang, Z. DeVito, Z. Lin, A. Desmaison, L. Antiga, and A. Lerer, “Automatic differentiation in pytorch,”NIPS 2017 Autodiff Workshop, 2017

  24. [24]

    Adam: A Method for Stochastic Optimization

    D. P. Kingma and J. Ba, “Adam: A method for stochastic optimization,”arXiv preprint arXiv:1412.6980, 2014

  25. [25]

    On the limited memory bfgs method for large scale opti- mization,

    D. C. Liu and J. Nocedal, “On the limited memory bfgs method for large scale opti- mization,”Mathematical programming, vol. 45, no. 1, pp. 503–528, 1989

  26. [26]

    Natural frequencies of rectangular plates using characteristic orthogonal polynomials in rayleigh-ritz method,

    R. B. Bhat, “Natural frequencies of rectangular plates using characteristic orthogonal polynomials in rayleigh-ritz method,”Journal of sound and vibration, vol. 102, no. 4, pp. 493–499, 1985

  27. [27]

    The theory of connections: Connecting points,

    D. Mortari, “The theory of connections: Connecting points,”Mathematics, vol. 5, no. 4, p. 57, 2017

  28. [28]

    The multivariate theory of functional connec- tions: Theory, proofs, and application in partial differential equations,

    C. Leake, H. Johnston, and D. Mortari, “The multivariate theory of functional connec- tions: Theory, proofs, and application in partial differential equations,”Mathematics, vol. 8, no. 8, p. 1303, 2020

  29. [29]

    Deep theory of functional connections: A new method for estimating the solutions of partial differential equations,

    C. Leake and D. Mortari, “Deep theory of functional connections: A new method for estimating the solutions of partial differential equations,”Machine learning and knowledge extraction, vol. 2, no. 1, pp. 37–55, 2020

  30. [30]

    Physics-informed functional link with theory of functional connections technique for solving differential equations,

    I. Sahu, S. Kumar, and S. Chakraverty, “Physics-informed functional link with theory of functional connections technique for solving differential equations,”Neurocomputing, p. 132795, 2026

  31. [31]

    High accuracy least-squares solutions of nonlin- ear differential equations,

    D. Mortari, H. Johnston, and L. Smith, “High accuracy least-squares solutions of nonlin- ear differential equations,”Journal of computational and applied mathematics, vol. 352, pp. 293–307, 2019

  32. [32]

    A mixed method for bending and free vibration of beams resting on a pasternak elastic foundation,

    W. Chen, C. L¨ u, and Z. Bian, “A mixed method for bending and free vibration of beams resting on a pasternak elastic foundation,”Applied mathematical modelling, vol. 28, no. 10, pp. 877–890, 2004. 28