The accurate mechanical analysis of thick-walled pressure vessel structures composed of advanced materials,such as hyperelastic and functionally graded materials(FGMs),is critical for ensuring their safety and optimiz...The accurate mechanical analysis of thick-walled pressure vessel structures composed of advanced materials,such as hyperelastic and functionally graded materials(FGMs),is critical for ensuring their safety and optimizing their design.However,conventional numerical methods can face challenges with the non-linearities inherent in hyperelasticity and the complex spatial variations in FGMs.This paper presents a novel hybrid numerical approach combining Physics-Informed Neural Networks(PINNs)with Finite Element Method(FEM)derived data for the robust analysis of thick-walled,axisymmetric,heterogeneous,hyperelastic pressure vessels with elliptical geometries.A PINN framework incorporating neo-Hookean constitutive relations is developed in MATLAB.To enhance training efficiency and accuracy,the PINN’s loss function is augmented with displacement data obtained from high-fidelity FEM simulations performed in ANSYS.The methodology is rigorously validated by comparing PINN-predicted displacement and von Mises stress fields against ANSYS benchmarks for various scenarios of FGMconfigurations(with material properties varying according to a power law)subjected to internal and external pressurization.The results demonstrate excellent agreement between the proposed hybrid PINN-FEMapproach and conventional FEMsolutions across all test cases,accurately capturing complex deformation patterns and stress concentrations.This study highlights the potential of data-augmented PINNs as an effective and accurate computational tool for tackling complex solid mechanics problems involving non-linearmaterials and significant heterogeneity,offering a promising avenue for future research in engineering design and analysis.展开更多
The dynamic evolution of fracture permeability presents a critical scientific challenge in rock masses.Understanding the mechanisms of rock mass permeability evolution is vital for engineering project design and opera...The dynamic evolution of fracture permeability presents a critical scientific challenge in rock masses.Understanding the mechanisms of rock mass permeability evolution is vital for engineering project design and operations.By integrating the discrete element method(DEM)with the finite element method(FEM),a numerical simulation framework for shear seepage in rough fractured shale has been developed to investigate the dynamic mechanisms of permeability evolution under varying confining pressures and during the shearing process.Numerical simulations were conducted on rough fractured samples under effective confining pressures ranging from 5 MPa to 20 MPa to monitor the aperture and permeability evolution of the fracture.The results of the numerical simulation are consistent with the experimental observations,indicating that both the shearing process and confining pressure significantly influence permeability.Moreover,the magnitude of the confining pressure is a crucial factor influencing the trend in permeability changes.Under a confining pressure of 5 MPa,fracture permeability initially increases significantly but decreases post-shearing.In contrast,a continuous decrease in fracture permeability is observed when the confining pressure exceeds 10 MPa.The results of the shear numerical simulation indicate that the confining pressure restricts fracture dilation during shearing,promotes the generation of rock debris,and decreases both the permeability and transmissivity of the fracture.The wear results obtained from numerical simulations are consistent with the experimental patterns and correlate with the joint roughness coefficient(JRC).This study proposed an effective numerical simulation method to reveal the evolution mechanism of fracture flow capacity,taking into account the wear of the fracture surface in shear simulations and the initial stress state of the rock in seepage simulations.This research explains the permeability evolution mechanism of fractured shale from a microscopic perspective,and the proposed numerical simulation method for shear seepage provides a powerful means to uncover the dynamic evolution mechanisms governing fracture permeability.展开更多
高位滑坡对建筑集群的冲击破坏时常导致严重的人员伤亡,基于光滑粒子流体动力学-离散元法-有限元法(smoothed particle hydrodynamics-discrete element method-finite element method,SPH-DEM-FEM)耦合的数值模型,开展了高位滑坡对框...高位滑坡对建筑集群的冲击破坏时常导致严重的人员伤亡,基于光滑粒子流体动力学-离散元法-有限元法(smoothed particle hydrodynamics-discrete element method-finite element method,SPH-DEM-FEM)耦合的数值模型,开展了高位滑坡对框架结构建筑群的冲击过程、建筑结构破坏机理、冲击力时程与框架柱关键点应力和弯矩等动力机制研究。研究结果表明:SPH-DEM-FEM耦合数值方法能够有效地模拟碎石土滑坡中土(SPH)石(DEM)混合物的抛射弹跳、爬高绕流冲击运动过程。考虑了常规建筑垂直、平行于滑坡流向的三排建筑组合布局,位于滑坡近端的纵向排列建筑表现为连续性倾倒破坏,横向排列的建筑则呈现整体倾倒破坏;因前排建筑群对滑坡冲击能量的耗散及滑坡自身摩擦耗能,位于滑坡后端建筑表现为引流面墙体和前排柱发生局部破坏,结构保持稳定,损毁程度依次为上游无建筑缓冲耗能的建筑>有横向排列的建筑>有纵向排列的建筑;纵向、横向排列的建筑冲击力衰减幅度分别31%、21%。横向框架建筑整体倾倒的损毁机制表现为框架柱的直接剪断或节点塑形铰链失效;纵向框架建筑连续性倾倒的损毁机制表现为前排框架柱的失效引起后排框架柱轴向压力和极限弯矩增加,持续冲击荷载超过其极限弯矩致使后排框架柱发生弯曲破坏,最终结构倾倒。系统能量在动能、内能和摩擦耗能间转化,其中摩擦耗能占65.5%,结构耗能占23.6%,动能快速下降与内能急剧增加是建筑破坏的关键特征。展开更多
文摘泥石流作为高破坏性混合流体,其携带的块石对框架结构的冲击机制尚未得到充分研究。为揭示含块石泥石流冲击框架结构的动力响应与损伤机制,基于光滑粒子流体动力学-离散元法-有限元法(smoothed particle hydrodynamics-discrete element method-finite element method,SPH-DEM-FEM)耦合数值方法,构建流体-块石-结构的多耦合数值模型,模拟不同冲击速度和角度下框架结构的损伤过程,并结合两相溃坝试验来验证模型有效性。研究表明:泥石流冲击导致结构损伤经历“接触-扩散-反弹-堆积/冲击”四个阶段,当冲击速度超过6.00 m/s时,结构产生不可恢复损伤,且块石阻隔作用使流体上部冲击力大于下部,引发结构中部最先发生集中损伤;此外,冲击力峰值随速度和角度增大呈非线性增长,10.00 m/s与90°工况下框架柱底冲击力达497.17 kN,超过结构抗冲击承载力;最后,数值模拟与经验公式所得冲击力结果误差在13.95%~29.00%,数量级一致,验证了模型可靠性。研究结果可为泥石流高发区框架结构的抗冲击设计提供参考。
文摘The accurate mechanical analysis of thick-walled pressure vessel structures composed of advanced materials,such as hyperelastic and functionally graded materials(FGMs),is critical for ensuring their safety and optimizing their design.However,conventional numerical methods can face challenges with the non-linearities inherent in hyperelasticity and the complex spatial variations in FGMs.This paper presents a novel hybrid numerical approach combining Physics-Informed Neural Networks(PINNs)with Finite Element Method(FEM)derived data for the robust analysis of thick-walled,axisymmetric,heterogeneous,hyperelastic pressure vessels with elliptical geometries.A PINN framework incorporating neo-Hookean constitutive relations is developed in MATLAB.To enhance training efficiency and accuracy,the PINN’s loss function is augmented with displacement data obtained from high-fidelity FEM simulations performed in ANSYS.The methodology is rigorously validated by comparing PINN-predicted displacement and von Mises stress fields against ANSYS benchmarks for various scenarios of FGMconfigurations(with material properties varying according to a power law)subjected to internal and external pressurization.The results demonstrate excellent agreement between the proposed hybrid PINN-FEMapproach and conventional FEMsolutions across all test cases,accurately capturing complex deformation patterns and stress concentrations.This study highlights the potential of data-augmented PINNs as an effective and accurate computational tool for tackling complex solid mechanics problems involving non-linearmaterials and significant heterogeneity,offering a promising avenue for future research in engineering design and analysis.
基金funded by the Joint Funds of the National Natural Science Foundation of China(Grant No.U23A20671)the Major Project of Inner Mongolia Science and Technology(Grant No.2021ZD0034)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engi-neering(Grant No.Z021003).
文摘The dynamic evolution of fracture permeability presents a critical scientific challenge in rock masses.Understanding the mechanisms of rock mass permeability evolution is vital for engineering project design and operations.By integrating the discrete element method(DEM)with the finite element method(FEM),a numerical simulation framework for shear seepage in rough fractured shale has been developed to investigate the dynamic mechanisms of permeability evolution under varying confining pressures and during the shearing process.Numerical simulations were conducted on rough fractured samples under effective confining pressures ranging from 5 MPa to 20 MPa to monitor the aperture and permeability evolution of the fracture.The results of the numerical simulation are consistent with the experimental observations,indicating that both the shearing process and confining pressure significantly influence permeability.Moreover,the magnitude of the confining pressure is a crucial factor influencing the trend in permeability changes.Under a confining pressure of 5 MPa,fracture permeability initially increases significantly but decreases post-shearing.In contrast,a continuous decrease in fracture permeability is observed when the confining pressure exceeds 10 MPa.The results of the shear numerical simulation indicate that the confining pressure restricts fracture dilation during shearing,promotes the generation of rock debris,and decreases both the permeability and transmissivity of the fracture.The wear results obtained from numerical simulations are consistent with the experimental patterns and correlate with the joint roughness coefficient(JRC).This study proposed an effective numerical simulation method to reveal the evolution mechanism of fracture flow capacity,taking into account the wear of the fracture surface in shear simulations and the initial stress state of the rock in seepage simulations.This research explains the permeability evolution mechanism of fractured shale from a microscopic perspective,and the proposed numerical simulation method for shear seepage provides a powerful means to uncover the dynamic evolution mechanisms governing fracture permeability.
文摘高位滑坡对建筑集群的冲击破坏时常导致严重的人员伤亡,基于光滑粒子流体动力学-离散元法-有限元法(smoothed particle hydrodynamics-discrete element method-finite element method,SPH-DEM-FEM)耦合的数值模型,开展了高位滑坡对框架结构建筑群的冲击过程、建筑结构破坏机理、冲击力时程与框架柱关键点应力和弯矩等动力机制研究。研究结果表明:SPH-DEM-FEM耦合数值方法能够有效地模拟碎石土滑坡中土(SPH)石(DEM)混合物的抛射弹跳、爬高绕流冲击运动过程。考虑了常规建筑垂直、平行于滑坡流向的三排建筑组合布局,位于滑坡近端的纵向排列建筑表现为连续性倾倒破坏,横向排列的建筑则呈现整体倾倒破坏;因前排建筑群对滑坡冲击能量的耗散及滑坡自身摩擦耗能,位于滑坡后端建筑表现为引流面墙体和前排柱发生局部破坏,结构保持稳定,损毁程度依次为上游无建筑缓冲耗能的建筑>有横向排列的建筑>有纵向排列的建筑;纵向、横向排列的建筑冲击力衰减幅度分别31%、21%。横向框架建筑整体倾倒的损毁机制表现为框架柱的直接剪断或节点塑形铰链失效;纵向框架建筑连续性倾倒的损毁机制表现为前排框架柱的失效引起后排框架柱轴向压力和极限弯矩增加,持续冲击荷载超过其极限弯矩致使后排框架柱发生弯曲破坏,最终结构倾倒。系统能量在动能、内能和摩擦耗能间转化,其中摩擦耗能占65.5%,结构耗能占23.6%,动能快速下降与内能急剧增加是建筑破坏的关键特征。
