Pub Date : 2024-10-18DOI: 10.1016/j.enganabound.2024.105994
The frost damage of rock mass poses a serious threat to the safety and stability of tunnels in cold regions, and the related thermo-hydro-mechanical (THM) coupling model under low-temperature conditions has been a key focus of research. This paper proposed a cryogenic THM coupled model (TOUGH-FEMM) to study the frost heave behavior of cold-region tunnels. Key issues including heat transfer, thermal stress, water-ice phase transition, unfrozen water, frost heave deformation, and ice-rock interaction are systematically addressed in the proposed model. Specifically, frost pressure in pores and cracks is derived separately to better simulate the ice expansion effect in rock masses. The proposed model is first validated against an experimental test and then applied to a practical cold-region tunnel to reveal the evolution of temperature, frost pressure and frost heave fields, as well as the tunnel stability. Moreover, the effects of cracks and frost damage on tunnel stability under freeze-thaw cycles are discussed. The work detailed herein provides an efficient tool for the THM coupled process in cold-region tunnels.
{"title":"A TOUGH-FEMM based cryogenic THM coupled model and its application to cold-region tunnels","authors":"","doi":"10.1016/j.enganabound.2024.105994","DOIUrl":"10.1016/j.enganabound.2024.105994","url":null,"abstract":"<div><div>The frost damage of rock mass poses a serious threat to the safety and stability of tunnels in cold regions, and the related thermo-hydro-mechanical (THM) coupling model under low-temperature conditions has been a key focus of research. This paper proposed a cryogenic THM coupled model (TOUGH-FEMM) to study the frost heave behavior of cold-region tunnels. Key issues including heat transfer, thermal stress, water-ice phase transition, unfrozen water, frost heave deformation, and ice-rock interaction are systematically addressed in the proposed model. Specifically, frost pressure in pores and cracks is derived separately to better simulate the ice expansion effect in rock masses. The proposed model is first validated against an experimental test and then applied to a practical cold-region tunnel to reveal the evolution of temperature, frost pressure and frost heave fields, as well as the tunnel stability. Moreover, the effects of cracks and frost damage on tunnel stability under freeze-thaw cycles are discussed. The work detailed herein provides an efficient tool for the THM coupled process in cold-region tunnels.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445274","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}
Pub Date : 2024-10-17DOI: 10.1016/j.enganabound.2024.105992
The capability of dealing with the advective transport term constitutes a challenging issue for the performance of the majority of the numerical techniques, which significantly lose their precision with the increasing in the relative magnitude of this term. Recently, a new boundary element technique called direct interpolation (DIBEM) has emerged, mainly characterized by the approximation of the entire kernel of the remaining domain integrals. The DIBEM model has been successfully applied to several scalar field problems and recently applied to certain diffusive–advective problems with superior accuracy compared to dual reciprocity formulation (DRBEM). Using DIBEM, a broader range of precise responses for flows with higher Peclet numbers can be reached beyond a lower computational cost due to the simplicity of its matrix operations. These advantages are due DIBEM concept that employs a simple interpolation procedure to approximate the kernel of the advective domain integral. However, it was noticed that in some physical scenarios with spatial variation in the velocity field, the accuracy of DIBEM did not have the same quality observed in other applications. Therefore, this work presents a new DIBEM model so that the integral equations include the explicit calculation of spatial derivatives and simultaneously solve the variation of the divergent velocity field if this is not zero. Conversely, reactive and source terms were also included to expand numerical comparisons. Thus, in the proposed examples, the results of two DIBEM models, the standard (DIBEM-S) and the new, so-called alternative model (DIBEM-A), are compared with DRBEM and also with available analytical solutions.
{"title":"A novel direct interpolation boundary element method formulation for solving diffusive–advective problems","authors":"","doi":"10.1016/j.enganabound.2024.105992","DOIUrl":"10.1016/j.enganabound.2024.105992","url":null,"abstract":"<div><div>The capability of dealing with the advective transport term constitutes a challenging issue for the performance of the majority of the numerical techniques, which significantly lose their precision with the increasing in the relative magnitude of this term. Recently, a new boundary element technique called direct interpolation (DIBEM) has emerged, mainly characterized by the approximation of the entire kernel of the remaining domain integrals. The DIBEM model has been successfully applied to several scalar field problems and recently applied to certain diffusive–advective problems with superior accuracy compared to dual reciprocity formulation (DRBEM). Using DIBEM, a broader range of precise responses for flows with higher Peclet numbers can be reached beyond a lower computational cost due to the simplicity of its matrix operations. These advantages are due DIBEM concept that employs a simple interpolation procedure to approximate the kernel of the advective domain integral. However, it was noticed that in some physical scenarios with spatial variation in the velocity field, the accuracy of DIBEM did not have the same quality observed in other applications. Therefore, this work presents a new DIBEM model so that the integral equations include the explicit calculation of spatial derivatives and simultaneously solve the variation of the divergent velocity field if this is not zero. Conversely, reactive and source terms were also included to expand numerical comparisons. Thus, in the proposed examples, the results of two DIBEM models, the standard (DIBEM-S) and the new, so-called alternative model (DIBEM-A), are compared with DRBEM and also with available analytical solutions.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445273","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}
Pub Date : 2024-10-17DOI: 10.1016/j.enganabound.2024.105989
The existing epilepsy detection models focus more on local information than the true meaning of long-range dependence when capturing time–frequency image features. This results in imprecise feature vector extraction and room for optimization of detection accuracy. AttenEpilepsy is a novel 2D convolutional network model that uses a multi-head self-attention mechanism to classify epileptic seizure periods, inter-seizure periods, and health states of single-channel EEG signals. The AttenEpilepsy model consists of two parts, namely feature extraction and time–frequency context encoding (STCE). A feature extraction method combining multi-path convolution and adaptive hybrid feature recalibration is proposed, in which multi-path convolution with convolution kernels of different sizes is used to extract relevant multi-scale features from time–frequency images. STCE consists of two modules: multi-head self-attention and causal convolution. A modified multi-head self-attention mechanism is used to model the extracted time–frequency features, and causal convolution is used to analyse the frequency information on the time dependencies. A public dataset from the University of Bonn Epilepsy Research Center is used to evaluate the performance of the AttenEpilepsy model. The experimental results show that the AttenEpilepsy model achieved accuracy (AC), sensitivity (SE), specificity (SP), and F1 score (F1) of 99.81%, 99.82%, 99.89%, and 99.83%, respectively. Further testing of the robustness of the model is conducted by introducing various types of noise into the input data. The proposed AttenEpilepsy network model outperforms the state-of-the-art in terms of various evaluation metrics.
{"title":"AttenEpilepsy: A 2D convolutional network model based on multi-head self-attention","authors":"","doi":"10.1016/j.enganabound.2024.105989","DOIUrl":"10.1016/j.enganabound.2024.105989","url":null,"abstract":"<div><div>The existing epilepsy detection models focus more on local information than the true meaning of long-range dependence when capturing time–frequency image features. This results in imprecise feature vector extraction and room for optimization of detection accuracy. AttenEpilepsy is a novel 2D convolutional network model that uses a multi-head self-attention mechanism to classify epileptic seizure periods, inter-seizure periods, and health states of single-channel EEG signals. The AttenEpilepsy model consists of two parts, namely feature extraction and time–frequency context encoding (STCE). A feature extraction method combining multi-path convolution and adaptive hybrid feature recalibration is proposed, in which multi-path convolution with convolution kernels of different sizes is used to extract relevant multi-scale features from time–frequency images. STCE consists of two modules: multi-head self-attention and causal convolution. A modified multi-head self-attention mechanism is used to model the extracted time–frequency features, and causal convolution is used to analyse the frequency information on the time dependencies. A public dataset from the University of Bonn Epilepsy Research Center is used to evaluate the performance of the AttenEpilepsy model. The experimental results show that the AttenEpilepsy model achieved accuracy (AC), sensitivity (SE), specificity (SP), and F1 score (F1) of 99.81%, 99.82%, 99.89%, and 99.83%, respectively. Further testing of the robustness of the model is conducted by introducing various types of noise into the input data. The proposed AttenEpilepsy network model outperforms the state-of-the-art in terms of various evaluation metrics.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445272","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}
Pub Date : 2024-10-16DOI: 10.1016/j.enganabound.2024.105993
This paper introduces a mesoscopic peridynamic model aimed at predicting and analyzing the failure of steel fiber-reinforced concrete within the framework of ordinary state-based peridynamics. This model incorporates additional interface force terms to handle substantial differences in component sizes between the fibers and concrete matrix, as well as the intricate behavior at the interface. These terms facilitate the representation of bond and frictional forces based on experimental data and empirical formulas. Additionally, it allows for non-uniform discretization of fiber-matrix interactions to improve computational efficiency. Several typical numerical examples performed by the proposed model closely align with experimental data in terms of bonding and slip behavior at the interface, crack patterns, and p-crack mouth open displacement (P-CMOD) curves, demonstrating the rationality and applicability of the model for numerical analysis on deformation and failure of steel fiber-reinforced concrete.
{"title":"Numerical modeling and failure analysis of steel fiber-reinforced concrete beams in a reformulated mesoscopic peridynamic model","authors":"","doi":"10.1016/j.enganabound.2024.105993","DOIUrl":"10.1016/j.enganabound.2024.105993","url":null,"abstract":"<div><div>This paper introduces a mesoscopic peridynamic model aimed at predicting and analyzing the failure of steel fiber-reinforced concrete within the framework of ordinary state-based peridynamics. This model incorporates additional interface force terms to handle substantial differences in component sizes between the fibers and concrete matrix, as well as the intricate behavior at the interface. These terms facilitate the representation of bond and frictional forces based on experimental data and empirical formulas. Additionally, it allows for non-uniform discretization of fiber-matrix interactions to improve computational efficiency. Several typical numerical examples performed by the proposed model closely align with experimental data in terms of bonding and slip behavior at the interface, crack patterns, and p-crack mouth open displacement (P-CMOD) curves, demonstrating the rationality and applicability of the model for numerical analysis on deformation and failure of steel fiber-reinforced concrete.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441280","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}
Pub Date : 2024-10-15DOI: 10.1016/j.enganabound.2024.105997
Meshless methods are valuable tools for real-time subsurface flow modeling and are particularly beneficial for adaptively adjusting node positions when incorporating supplementary measurements. However, an algorithm is required for automatically generating high-quality meshless nodes to adapt to irregularly shaped aquifers and arbitrarily distributed wells. This paper introduces a three-dimensional adaptive meshless node placement technique based on advancing front nodes and proposes a sigmoid exclusion circle to ensure adaptability to specific positions of interest. It is crucial for groundwater simulations to have specified computational points at wellbore locations. The generated meshless nodes were used as computational points in the generalized finite difference method. The node quality was assessed by comparing the numerical solutions to the analytical solution, achieving errors of the order of 10–12. The application scenarios of irregularly shaped aquifers demonstrated the high efficiency of the three-dimensional node placement in generating up to 10,000 nodes in <5 s. The effectiveness of the algorithm was verified using three-dimensional irregular computational domains. The algorithm could be easily adapted to two-dimensional problems, and an irregular boundary example is presented. The validation and application cases highlighted the versatility of the proposed method and established its potential for real-world hydrogeological applications.
{"title":"An efficient approach of meshless node placement in three-dimensional subsurface flow modeling","authors":"","doi":"10.1016/j.enganabound.2024.105997","DOIUrl":"10.1016/j.enganabound.2024.105997","url":null,"abstract":"<div><div>Meshless methods are valuable tools for real-time subsurface flow modeling and are particularly beneficial for adaptively adjusting node positions when incorporating supplementary measurements. However, an algorithm is required for automatically generating high-quality meshless nodes to adapt to irregularly shaped aquifers and arbitrarily distributed wells. This paper introduces a three-dimensional adaptive meshless node placement technique based on advancing front nodes and proposes a sigmoid exclusion circle to ensure adaptability to specific positions of interest. It is crucial for groundwater simulations to have specified computational points at wellbore locations. The generated meshless nodes were used as computational points in the generalized finite difference method. The node quality was assessed by comparing the numerical solutions to the analytical solution, achieving errors of the order of 10<sup>–12</sup>. The application scenarios of irregularly shaped aquifers demonstrated the high efficiency of the three-dimensional node placement in generating up to 10,000 nodes in <5 s. The effectiveness of the algorithm was verified using three-dimensional irregular computational domains. The algorithm could be easily adapted to two-dimensional problems, and an irregular boundary example is presented. The validation and application cases highlighted the versatility of the proposed method and established its potential for real-world hydrogeological applications.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438141","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}
Pub Date : 2024-10-15DOI: 10.1016/j.enganabound.2024.105979
This paper proposes a hybrid RANS/TEBEM method to conduct self-propulsion prediction in calm water with accuracy and improve its efficiency by means of larger time step. In the coupling procedure, the rotating propeller is represented by time-averaged, spatial inhomogeneous body force field obtained from the potential flow solver based on Taylor Expansion Boundary Element Method (TEBEM) in RANS simulation. Effective wake is evaluated by subtracting induced velocities computed by potential solver from total velocities in RANS solver at a coupling plane upstream of propeller plane. The influence of coupling plane position and grid density on the numerical results is also investigated. Through KCS and KVLCC2 cases, it is shown that the predicted value of propeller revolution speed is within 4% of the experimental value, verifying the robustness and reliability of this method.
{"title":"Self-propulsion performance prediction in calm water based on RANS/TEBEM coupling method","authors":"","doi":"10.1016/j.enganabound.2024.105979","DOIUrl":"10.1016/j.enganabound.2024.105979","url":null,"abstract":"<div><div>This paper proposes a hybrid RANS/TEBEM method to conduct self-propulsion prediction in calm water with accuracy and improve its efficiency by means of larger time step. In the coupling procedure, the rotating propeller is represented by time-averaged, spatial inhomogeneous body force field obtained from the potential flow solver based on Taylor Expansion Boundary Element Method (TEBEM) in RANS simulation. Effective wake is evaluated by subtracting induced velocities computed by potential solver from total velocities in RANS solver at a coupling plane upstream of propeller plane. The influence of coupling plane position and grid density on the numerical results is also investigated. Through KCS and KVLCC2 cases, it is shown that the predicted value of propeller revolution speed is within 4% of the experimental value, verifying the robustness and reliability of this method.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438082","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}
Pub Date : 2024-10-14DOI: 10.1016/j.enganabound.2024.105996
The grain-based model is used to study the time-independent and time-dependent behavior in damage evolution and fracture patterns of brittle rocks. The standard loading approach (i.e., the model is loaded by applying constant velocities at boundaries of the model based on the test procedure) is the primary loading approach for quasi-static simulation in the grain-based model, but the computational efficiency of this approach is relatively low. We developed herein the internal-strain loading approach, a more efficient loading approach, for simulating the mechanical behavior of brittle rocks. The internal-strain loading approach was embedded into the three-dimensional discrete element grain-based model (3DEC-GBM). The internal-strain loading approach was compared to the standard loading approach using triaxial compression, direct tensile, and direct shear simulations. The results showed that the internal-strain loading approach was able to accurately reproduce both the deformation behavior and strength of the laboratory experiment. Compared with the standard loading approach, where the axial velocity of two plates was 0.0025 m s−1 in the compression simulation, the internal-strain loading approach can reduce the model run times by up to ten times. We conclude that the proposed internal-strain loading approach is a powerful tool that can improve the computational efficiency of the grain-based model.
基于晶粒的模型用于研究脆性岩石损伤演变和断裂模式中与时间无关和与时间有关的行为。标准加载法（即根据测试程序在模型边界施加恒定速度加载模型）是晶粒模型准静态模拟的主要加载方法，但这种方法的计算效率相对较低。我们在此开发了一种更有效的加载方法--内应变加载法，用于模拟脆性岩石的力学行为。内应变加载方法被嵌入到三维离散元晶粒模型（3DEC-GBM）中。通过三轴压缩、直接拉伸和直接剪切模拟，将内应变加载法与标准加载法进行了比较。结果表明，内应变加载法能够准确再现实验室实验的变形行为和强度。与标准加载方法（压缩模拟中两块板的轴向速度为 0.0025 m s-1）相比，内应变加载方法可将模型运行时间减少多达 10 倍。我们的结论是，所提出的内应变加载方法是一种强大的工具，可以提高基于晶粒模型的计算效率。
{"title":"An internal-strain loading approach for quasi-static fracturing in brittle rocks via the grain-based model","authors":"","doi":"10.1016/j.enganabound.2024.105996","DOIUrl":"10.1016/j.enganabound.2024.105996","url":null,"abstract":"<div><div>The grain-based model is used to study the time-independent and time-dependent behavior in damage evolution and fracture patterns of brittle rocks. The standard loading approach (i.e., the model is loaded by applying constant velocities at boundaries of the model based on the test procedure) is the primary loading approach for quasi-static simulation in the grain-based model, but the computational efficiency of this approach is relatively low. We developed herein the internal-strain loading approach, a more efficient loading approach, for simulating the mechanical behavior of brittle rocks. The internal-strain loading approach was embedded into the three-dimensional discrete element grain-based model (3DEC-GBM). The internal-strain loading approach was compared to the standard loading approach using triaxial compression, direct tensile, and direct shear simulations. The results showed that the internal-strain loading approach was able to accurately reproduce both the deformation behavior and strength of the laboratory experiment. Compared with the standard loading approach, where the axial velocity of two plates was 0.0025 m s<sup>−1</sup> in the compression simulation, the internal-strain loading approach can reduce the model run times by up to ten times. We conclude that the proposed internal-strain loading approach is a powerful tool that can improve the computational efficiency of the grain-based model.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432088","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}
Pub Date : 2024-10-14DOI: 10.1016/j.enganabound.2024.105985
The scattering of gravity waves interacting with an array of multiple surface-piercing thin porous barriers is explored based on the hypothesis of linearized potential flow for finite water depth. The barriers are assumed to be stationed at a finite distance from each other and on the lee side of the dock. Also, it is hypothesized that the waves passing through the porous barriers follow Darcy’s law. The wave properties such as reflection and transmission coefficients, dissipation of wave energy, and horizontal wave force on the floating rigid dock are studied to check the effectiveness of different numbers of barriers and length () of barriers, their porosity, the spacing between barriers, and the distance between the last barrier and the floating rigid dock. It has been witnessed that more surface piercing barriers are obviously helpful in relieving the force due to the wave interaction with the floating rigid dock. It is noticed that implementing four perforated barriers not only reduces reflection by around 70% but also enhances wave energy dissipation by 90%, with equal size of barrier lengths being the most effective. The porous barriers are more conducive to alleviating the wave force than the rigid barriers. Additionally, it is observed that there is zero reflection when the barriers’ length is set at and set porosity at 1.212 (where is the water depth). On the other hand, the critical incidence angle for reflection is also noticed with barriers of length . Further, the expansion of the normalized spacing between the structures helps reflect and transmit the waves along with the dissipation of wave energy to display a periodic pattern. The free surface elevation plots certainly help to fortify the claim of having multiple barriers as a tool to mitigate the wave force on the floating dock.
{"title":"Wave attenuation on a floating rigid dock by multiple surface-piercing vertical thin perforated barriers","authors":"","doi":"10.1016/j.enganabound.2024.105985","DOIUrl":"10.1016/j.enganabound.2024.105985","url":null,"abstract":"<div><div>The scattering of gravity waves interacting with an array of multiple surface-piercing thin porous barriers is explored based on the hypothesis of linearized potential flow for finite water depth. The barriers are assumed to be stationed at a finite distance from each other and on the lee side of the dock. Also, it is hypothesized that the waves passing through the porous barriers follow Darcy’s law. The wave properties such as reflection and transmission coefficients, dissipation of wave energy, and horizontal wave force on the floating rigid dock are studied to check the effectiveness of different numbers of barriers and length (<span><math><mi>H</mi></math></span>) of barriers, their porosity, the spacing between barriers, and the distance between the last barrier and the floating rigid dock. It has been witnessed that more surface piercing barriers are obviously helpful in relieving the force due to the wave interaction with the floating rigid dock. It is noticed that implementing four perforated barriers not only reduces reflection by around 70% but also enhances wave energy dissipation by 90%, with equal size of barrier lengths being the most effective. The porous barriers are more conducive to alleviating the wave force than the rigid barriers. Additionally, it is observed that there is zero reflection when the barriers’ length is set at <span><math><mrow><mi>H</mi><mo>/</mo><mi>h</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>7</mn></mrow></math></span> and set porosity at 1.212 (where <span><math><mi>h</mi></math></span> is the water depth). On the other hand, the critical incidence angle <span><math><mrow><mn>31</mn><mo>.</mo><mn>81</mn><mo>°</mo></mrow></math></span> for reflection is also noticed with barriers of length <span><math><mrow><mi>H</mi><mo>/</mo><mi>h</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>6</mn></mrow></math></span>. Further, the expansion of the normalized spacing between the structures helps reflect and transmit the waves along with the dissipation of wave energy to display a periodic pattern. The free surface elevation plots certainly help to fortify the claim of having multiple barriers as a tool to mitigate the wave force on the floating dock.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432089","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}
Pub Date : 2024-10-11DOI: 10.1016/j.enganabound.2024.105990
In this paper, the radial basis function (RBF) without shaped parameter is utilized in the radial basis reproducing kernel particle method (RRKPM), and an improved radial basis reproducing kernel particle method (IRRKPM) is proposed. Compared with traditional RKPM, the IRRKPM effectively reduces the impact of different kernel functions on calculation precision, and is further employed to examine geometrically nonlinear problems associated with shape memory alloys (SMAs). The displacement boundary condition is enforced via the penalty function method, while the Galerkin integration method in its weak form, along with the total Lagrangian (TL) approach, is utilized to derive the geometrically nonlinear equations for SMAs within the IRRKPM framework. The equilibrium equations are then solved using the Newton Raphson (N-R) iterative method. The impact of the different penalty factor and the radius control parameter of influence domain on errors is analyzed, the computational precision of the IRRKPM is compared with the RRKPM, and the computational stability is evaluated. Finally, the suitability of the IRRKPM for the analysis of geometrically nonlinearity problems in SMAs are confirmed through specific numerical examples.
{"title":"An improved radial basis reproducing kernel particle method for geometrically nonlinear problem analysis of SMAs","authors":"","doi":"10.1016/j.enganabound.2024.105990","DOIUrl":"10.1016/j.enganabound.2024.105990","url":null,"abstract":"<div><div>In this paper, the radial basis function (RBF) without shaped parameter is utilized in the radial basis reproducing kernel particle method (RRKPM), and an improved radial basis reproducing kernel particle method (IRRKPM) is proposed. Compared with traditional RKPM, the IRRKPM effectively reduces the impact of different kernel functions on calculation precision, and is further employed to examine geometrically nonlinear problems associated with shape memory alloys (SMAs). The displacement boundary condition is enforced via the penalty function method, while the Galerkin integration method in its weak form, along with the total Lagrangian (TL) approach, is utilized to derive the geometrically nonlinear equations for SMAs within the IRRKPM framework. The equilibrium equations are then solved using the Newton Raphson (N-R) iterative method. The impact of the different penalty factor and the radius control parameter of influence domain on errors is analyzed, the computational precision of the IRRKPM is compared with the RRKPM, and the computational stability is evaluated. Finally, the suitability of the IRRKPM for the analysis of geometrically nonlinearity problems in SMAs are confirmed through specific numerical examples.</div></div>","PeriodicalId":51039,"journal":{"name":"Engineering Analysis with Boundary Elements","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424546","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}
Pub Date : 2024-10-10DOI: 10.1016/j.enganabound.2024.105987
Accurate and efficient simulation of dynamic hydraulic fracturing of the saturated porous media has always been a pivotal topic in the oil and gas extraction. Leveraging the Numerical Manifold Method (NMM) and its inherent cutting technique, this paper proposes a fully coupled hydraulic fracturing model based on the u-p format, which incorporates the overall momentum balance and continuity conditions in both porous media and fractures. NMM approximations and the Newmark implicit algorithm are employed respectively to discretize the spatial and time domains, and the resulting system is solved based on the Newton-Raphson method. By imposing flow boundary conditions on the fracture surfaces, the present model accounts for fluid loss without introducing extra filtration coefficients. Using the Mohr-Coulomb-based LT criterion and the maximum circumferential stress criterion to determine whether crack propagation has occurred and crack propagation direction respectively, the present model is capable of simulating initiation and development of multiple cracks under hydraulic stimulations. Through modeling the KGD hydraulic fracturing, hydraulic fracturing of a pre-cracked cubic specimen and fracture interference phenomena during expansion of multiple fracture ports of a single injection well, accuracy and effectiveness of the model are validated.
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