{"title":"Method of fundamental solutions formulations for biharmonic problems","authors":"Csaba Gáspár , Andreas Karageorghis","doi":"10.1016/j.enganabound.2025.106180","DOIUrl":"10.1016/j.enganabound.2025.106180","url":null,"abstract":"<div><div>We consider various method of fundamental solution (MFS) formulations for the numerical solution of two-dimensional boundary value problems (BVPs) governed by the homogeneous biharmonic equation. The motivation for employing the proposed techniques comes from the corresponding boundary integral representations. These are carefully analyzed in the case the domain of the BVP under consideration is a disk. The results of this analysis detect a potentially troublesome case in one of the proposed MFS approaches. Numerical results confirm the analytical findings for more general domains.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"175 ","pages":"Article 106180"},"PeriodicalIF":4.2,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Youjun Ning , Xuanhao Lin , Dayong Chen , Haofeng Chen , Mangong Zhang
{"title":"Study on the applications of different cover methods in numerical manifold method (NMM)","authors":"Youjun Ning , Xuanhao Lin , Dayong Chen , Haofeng Chen , Mangong Zhang","doi":"10.1016/j.enganabound.2025.106192","DOIUrl":"10.1016/j.enganabound.2025.106192","url":null,"abstract":"<div><div>Numerical manifold method (NMM) is a powerful unified continuous-discontinuous method due to its dual cover systems and the flexibility of the cover types. In this work, to better solve problems with various discontinuity geometry characteristics by NMM, the finite element method (FEM) mesh and the NMM traditional regular mathematical mesh are employed to construct finite covers for NMM, respectively. Moreover, an independent cover method by which a single physical domain is represented as one manifold element is also introduced. Different types of covers are coupled to simulate the uniaxial loading of mesoscopic concrete models, as well as a rock slope slumping model. The corresponding deformation, fracturing and failure processes are numerically reproduced satisfactorily and consistently by NMM with different combinations of the cover methods. Simulations are also carried out to investigate the important problem of dynamic sliding for discontinua by employing different cover methods in NMM simulations. The results in this work indicate that an appropriate application of the cover methods benefits the reasonable construction of NMM simulation models by avoiding unfavorable extremely small or elongated manifold elements. Meanwhile, the simulation efficiency could be improved due to the reduction of the manifold element number and the contact number at discontinuities.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106192"},"PeriodicalIF":4.2,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlocal general particle dynamics for fluid-structure interaction problems considering the structural failure","authors":"Y.L. Li , X.P. Zhou","doi":"10.1016/j.enganabound.2025.106179","DOIUrl":"10.1016/j.enganabound.2025.106179","url":null,"abstract":"<div><div>Modeling the structural failures induced by fluid-structure interaction (FSI) are crucial because it dominates many engineering problems. In this paper, a nonlocal general particle dynamic (NGPD) method is proposed to solve the FSI problems considering the structural failure. In this framework, the governing equations for fluid and solid are reformulated by introducing nonlocal theories. The tensile strength criterion is introduced to simulate crack initiation and propagation. A coupled strategy is proposed to calculate the interaction forces in the fluid-structure interface. The different particle spacings are utilized to discretize the fluid and solid computational domains to enhance the accuracy of modeling structural failure. A series of benchmark examples involving fluid and solid, and FSI models, are studied to demonstrate the accuracy, robustness, and stability of the proposed method. Subsequently, the failure of a tank floor under hydrostatic pressure and the Koyna Dam are illustrated to demonstrate the efficacy and versatility of the method in modeling structural failure induced by FSI. The numerical results demonstrate that the proposed NGPD framework is suitable for simulating fluid-structure interaction problems considering the structural failure.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106179"},"PeriodicalIF":4.2,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kim Q. Tran , Thoi V. Duong , Tien-Dat Hoang , Magd Abdel Wahab , Klaus Hackl , H. Nguyen-Xuan
{"title":"A new thermoelastic model for agglomerated and randomly-oriented CNT-reinforced bio-inspired materials: Temperature-dependent free vibration analysis of FG-CNTR-TPMS plates","authors":"Kim Q. Tran , Thoi V. Duong , Tien-Dat Hoang , Magd Abdel Wahab , Klaus Hackl , H. Nguyen-Xuan","doi":"10.1016/j.enganabound.2025.106157","DOIUrl":"10.1016/j.enganabound.2025.106157","url":null,"abstract":"<div><div>A new thermoelastic model is introduced to reveal equivalent mechanical and thermal properties of randomly oriented (RO), agglomerated carbon nanotube (CNT) inclusions within a matrix material. Thereafter, a bio-inspired FG-CNTR-TPMS material model is established through three typical triply periodic minimal surfaces (TPMS) microstructures reinforced with CNTs and functionally graded (FG) schemes. The free vibration behavior of macro-scale plates made from FG-CNTR-TPMS materials under thermal effects and material temperature dependencies is then devised. A new higher-order shear deformation (HSDT) five-variable plate theory incorporated with isogeometric analysis (IGA) is proposed to show its reliability and efficiency. Various material conditions have been thoroughly studied, emphasizing the influence of CNT reinforcement states and environment temperatures. While increasing the CNT volume fraction (<span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>r</mi></mrow></msub></math></span>) greatly improves the plate frequencies, the temperature rise (<span><math><mrow><mi>Δ</mi><mi>T</mi></mrow></math></span>) leads to an opposite influence. These properties can amplify or weaken the effects of porosity distributions on the plate’s natural frequencies both beneficial and unfavorable aspects. Notably, the outstanding elastic modulus of IWP-type TPMS enlarges the initial thermal stress and ratio between mechanical and thermal stiffness, causing greater impacts on plate behaviors in the thermal environment. In some exceptional cases, FG-CNTR-TPMS plates with P-type can exceed isotropic plates in stiffness-to-weight ratios, which is an extraordinary characteristic of porous structures. In various scenarios of CNT agglomeration, this natural phenomenon shows noticeable reductions in plate frequencies up to 40% when considering temperature changes. Bridging the gap between TPMS-based lattice structures and CNT-reinforced composites, this study contributes to advancing the knowledge of advanced bio-inspired materials. The findings from this work can revolutionize their potential applications in various engineering areas, particularly biomedical devices, energy storage, flexible electronics, advanced textiles, and soft robotics, where lightweight, high-strength, and temperature-resistant structural components are critical.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106157"},"PeriodicalIF":4.2,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical study on slag accumulation in solid rocket motor with a new Lagrangian-Euler coupled particle computational framework","authors":"Dudou Wang, Yuxiang Liu, Zhensheng Sun, Xueren Wang, Hongfu Qiang","doi":"10.1016/j.enganabound.2025.106187","DOIUrl":"10.1016/j.enganabound.2025.106187","url":null,"abstract":"<div><div>Slag accumulation is one of the key and most difficult problems in solid rocket motor (SRM) having submerged nozzles, which may cause severe ablation of insulation and even has a great influence on the interior ballistic performance. This study aims to establish a computational framework mainly based on a Lagrangian-Euler coupled particle model, which consider granular flow as a combination of smoke particle continuum phase and large particle discrete phase, to simulate two-phase flow and explore the characteristics of slag accumulation. The computational framework integrated particle injection model, <em>Al</em> particle combustion model and multiphase coupling model as well, and was verified by the Jet Propulsion Laboratory (JPL) nozzle numerical example. The result of the slag accumulation simulation are in good agreement with experiment data. It shows that, the slag starts to be produced after the motor is ignited, and the accumulation rate is larger at the initial time and gradually decreases. The influences of inject particle diameter in slag accumulation are explored. Discrete particles with larger peak diameter cause lower total combustion efficiency, lower conversion rate of <em>Al</em>, and higher slag rate. The particle size of <em>Al<sub>2</sub>O<sub>3</sub></em> smoke have the smallest contribution to the slag rate in the range of 1.5μm-2.5μm.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106187"},"PeriodicalIF":4.2,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-precision physics-informed extreme learning machines for evolving interface problems","authors":"Shaojie Zeng, Yijie Liang, Qinghui Zhang","doi":"10.1016/j.enganabound.2025.106171","DOIUrl":"10.1016/j.enganabound.2025.106171","url":null,"abstract":"<div><div>Neural network (NN) methods have been developed to solve interface problems recently. In comparison with conventional techniques (e.g., finite element method), the NN method enjoys the merits of meshless features, powerful ability to approximate complex interface geometries, and high accuracy. The current NN studies are mostly focused on elliptic interface problems. The methodology will cause difficulties for evolving (time-dependent) and moving interface problems. (a) The accuracy is also characterized by time discretization strategies; if the time step <span><math><mi>τ</mi></math></span> is small, the training time is unbearable. (b) At each time step, it is difficult to design the high-precision NNs because of involvement of complex interfaces, especially for the moving interfaces. This study is devoted to proposing the high-precision NN methods for the evolving and moving interface problems. The first method is based on the time stepping scheme. In every time step we develop piecewise extreme learning machine (ELM) to improve the accuracy of space discretization and reduce the training time. As a consequence, the optimal overall error with respect to the time, <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mi>τ</mi><mo>)</mo></mrow></mrow></math></span>, is achieved (for the backward Euler method). Evidently, the accuracy is still limited by <span><math><mi>τ</mi></math></span>. To improve the accuracy further, the second method is to treat the time dimension as an additional space dimension to formulate the equation in an extended time–space domain <span><math><mover><mrow><mi>Ω</mi></mrow><mrow><mo>̃</mo></mrow></mover></math></span>. A time–space piecewise ELM in <span><math><mover><mrow><mi>Ω</mi></mrow><mrow><mo>̃</mo></mrow></mover></math></span> is designed. The new method avoids the time stepping so that the training time is saved essentially, and the approximation errors are also reduced significantly. We note that the increase of dimension in <span><math><mover><mrow><mi>Ω</mi></mrow><mrow><mo>̃</mo></mrow></mover></math></span> does not yield additional computational complexities because of the dimensionless feature of NN techniques. A great many numerical experiments are executed to verify the accuracy and efficiency of the proposed methods, including two- and three-dimensional evolving and moving interface problems with the complex interface geometries. The comparisons with other NN methods, such as PINN, fully-connected NN, are also made.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106171"},"PeriodicalIF":4.2,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rini Jasmine Gladstone , Mohammad Amin Nabian , N. Sukumar , Ankit Srivastava , Hadi Meidani
{"title":"FO-PINN: A First-Order formulation for Physics-Informed Neural Networks","authors":"Rini Jasmine Gladstone , Mohammad Amin Nabian , N. Sukumar , Ankit Srivastava , Hadi Meidani","doi":"10.1016/j.enganabound.2025.106161","DOIUrl":"10.1016/j.enganabound.2025.106161","url":null,"abstract":"<div><div>Physics-Informed Neural Networks (PINNs) are a class of deep learning neural networks that learn the response of a physical system without any simulation data, and only by incorporating the governing partial differential equations (PDEs) in their loss function. While PINNs are successfully used for solving forward and inverse problems, their accuracy decreases significantly for parameterized systems and higher-order PDE problems. PINNs also have a soft implementation of boundary conditions resulting in boundary conditions not being exactly imposed everywhere on the boundary. With these challenges at hand, we present first-order physics-informed neural networks (FO-PINNs). These are PINNs that are trained using a first-order formulation of the PDE loss function. We show that, compared to standard PINNs, FO-PINNs offer significantly higher accuracy in solving parameterized systems, and reduce time-per-iteration by removing the extra backpropagations needed to compute the second or higher-order derivatives. Additionally, FO-PINNs can enable exact imposition of boundary conditions using approximate distance functions, which pose challenges when applied on high-order PDEs. Through four examples, we demonstrate the advantages of FO-PINNs over standard PINNs in terms of accuracy and training speedup.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106161"},"PeriodicalIF":4.2,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A coupled hydraulic-mechanical-chemical peridynamic model for simulating corrosion-induced failure of unsaturated reinforced concrete under hydraulic pressure","authors":"Shenhua Liu , Weizhong Chen , Jingqiang Yuan","doi":"10.1016/j.enganabound.2025.106177","DOIUrl":"10.1016/j.enganabound.2025.106177","url":null,"abstract":"<div><div>Underwater reinforced concrete is vulnerable to chloride corrosion, which reduces the durability of underwater concrete structures. In this paper, by introducing time-varying chloride ion diffusion and non-uniform corrosion expansion failure model, a chemical-hydraulic-mechanical coupling peridynamic model of reinforced concrete corrosion expansion failure process in actual underwater environment is established. The proposed model focuses both on the unsaturated transport process of water and chloride and the corrosion failure of unsaturated reinforced concrete under water pressure. The validity of proposed model is firstly verified by comparing with experimental results and theoretical solutions. Then, the whole process of corrosion expansion failure of underwater reinforced concrete is simulated by using this model. The numerical results show that the developed chemical-hydraulic-mechanical coupling peridynamic model can simulate the penetration of water and chloride in unsaturated concrete and the failure process of concrete caused by chloride corrosion under water pressure. Furthermore, the effects of water pressure on water / chloride ion transport and corrosion expansion damage of underwater reinforced concrete were studied.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106177"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlinear eigenvalue analysis of thermoviscous acoustic problems using an equivalent source method","authors":"Meng-Hui Liang, Chang-Jun Zheng, Yong-Bin Zhang, Liang Xu, Shuai Wang, Chuan-Xing Bi","doi":"10.1016/j.enganabound.2025.106162","DOIUrl":"10.1016/j.enganabound.2025.106162","url":null,"abstract":"<div><div>In this study, a nonlinear eigenvalue solver for the numerical solution of thermoviscous acoustic problems based on the equivalent source method (ESM) is developed. By using the idea of the ESM, the solutions to the thermoviscous formulations are coupled on the surface of the structure through the isothermal and non-slip conditions. The frequency-dependent nature of the transfer matrix in the system equation of ESM gives rise to a nonlinear eigenvalue problem (NLEP), presenting an additional challenge in the eigenvalue analysis. To tackle this issue, the contour integral method is employed to convert the NLEP into a generalized eigenvalue problem (GEVP). This contour integral method is effective for accurately identifying complex acoustic eigenvalues, which are frequently encountered in the context of thermoviscous acoustic problems. Numerical examples are provided to validate the effectiveness and accuracy of the proposed method, while simulations involving acoustic black hole and acoustic-structural interaction demonstrate its potential applicability in engineering applications.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":"174 ","pages":"Article 106162"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}