In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geo...In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geometrical interpretation of deformation state, the general form of strain energy density function was introduced. Using this function and variational methods the relations between material characteristics were achieved. All considerations are illustrated by a short theoretical example.展开更多
Whether the concept of effective stress and strain in elastic-plastic theory is still valid under the condition of finite deformation was mainly discussed. The uni-axial compression experiments in plane stress and pla...Whether the concept of effective stress and strain in elastic-plastic theory is still valid under the condition of finite deformation was mainly discussed. The uni-axial compression experiments in plane stress and plane strain states were chosen for study. In the two kinds of stress states, the stress-strain curve described by logarithm strain and rotated Kirchhoff stress matches the experiments data better than the curves defined by other stress-strain description.展开更多
Catastrophe theory was used to investigate the fracture behavior of thin-wall cylindrical tubes subjected to internal explosive pressure. Based on the energy theory and catastrophe theory, a cusp catastrophe model for...Catastrophe theory was used to investigate the fracture behavior of thin-wall cylindrical tubes subjected to internal explosive pressure. Based on the energy theory and catastrophe theory, a cusp catastrophe model for the fracture vas established, and a critical condition associated with the model is given.展开更多
A constant problem is to localize a number of acoustic sources, to separate their individual signals and to estimate their strengths in a propagation medium. An acoustic receiving array with signal processing algorith...A constant problem is to localize a number of acoustic sources, to separate their individual signals and to estimate their strengths in a propagation medium. An acoustic receiving array with signal processing algorithms is then used. The most widely used algorithm is the conventional beamforming algorithm but it has a very low resolution and high sidelobes that may cause a signal leakage problem. Several new signal processors for arrays of sensors are derived to evaluate the strengths of acoustic signals arriving at an array of sensors. In particular, we present the covariance vector estimator and the pseudoinverse of the array manifold matrix estimator. The covariance vector estimator uses only the correlations between sensors and the pseudoinverse of the array manifold matrix estimator operates with the minimum eigenvalues of the covariance matrix. Numerical and experimental results are presented.展开更多
Smoothed Particle Hydrodynamics (SPH) is fast emerging as a practically usefulcomputational simulation tool for a wide variety of engineering problems. SPH isalso gaining popularity as the back bone for fast and reali...Smoothed Particle Hydrodynamics (SPH) is fast emerging as a practically usefulcomputational simulation tool for a wide variety of engineering problems. SPH isalso gaining popularity as the back bone for fast and realistic animations in graphicsand video games. The Lagrangian and mesh-free nature of the method facilitates fastand accurate simulation of material deformation, interface capture, etc. Typically,particle-based methods would necessitate particle search and locate algorithms tobe implemented efficiently, as continuous creation of neighbor particle lists is acomputationally expensive step. Hence, it is advantageous to implement SPH, on modernmulti-core platforms with the help of High-Performance Computing (HPC) tools. Inthis work, the computational performance of an SPH algorithm is assessed on multicore Central Processing Unit (CPU) as well as massively parallel General PurposeGraphical Processing Units (GP-GPU). Parallelizing SPH faces several challenges suchas, scalability of the neighbor search process, force calculations, minimizing threaddivergence, achieving coalesced memory access patterns, balancing workload, ensuringoptimum use of computational resources, etc. While addressing some of these challenges,detailed analysis of performance metrics such as speedup, global load efficiency, globalstore efficiency, warp execution efficiency, occupancy, etc. is evaluated. The OpenMP andCompute Unified Device Architecture (CUDA) parallel programming models have beenused for parallel computing on Intel Xeon(R) E5-2630 multi-core CPU and NVIDIAQuadro M4000 and NVIDIA Tesla p100 massively parallel GPU architectures. Standardbenchmark problems from the Computational Fluid Dynamics (CFD) literature are chosen for the validation. The key concern of how to identify a suitable architecturefor mesh-less methods which essentially require heavy workload of neighbor search andevaluation of local force fields from neighbor interactions is addressed.展开更多
文摘In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geometrical interpretation of deformation state, the general form of strain energy density function was introduced. Using this function and variational methods the relations between material characteristics were achieved. All considerations are illustrated by a short theoretical example.
文摘Whether the concept of effective stress and strain in elastic-plastic theory is still valid under the condition of finite deformation was mainly discussed. The uni-axial compression experiments in plane stress and plane strain states were chosen for study. In the two kinds of stress states, the stress-strain curve described by logarithm strain and rotated Kirchhoff stress matches the experiments data better than the curves defined by other stress-strain description.
文摘Catastrophe theory was used to investigate the fracture behavior of thin-wall cylindrical tubes subjected to internal explosive pressure. Based on the energy theory and catastrophe theory, a cusp catastrophe model for the fracture vas established, and a critical condition associated with the model is given.
文摘A constant problem is to localize a number of acoustic sources, to separate their individual signals and to estimate their strengths in a propagation medium. An acoustic receiving array with signal processing algorithms is then used. The most widely used algorithm is the conventional beamforming algorithm but it has a very low resolution and high sidelobes that may cause a signal leakage problem. Several new signal processors for arrays of sensors are derived to evaluate the strengths of acoustic signals arriving at an array of sensors. In particular, we present the covariance vector estimator and the pseudoinverse of the array manifold matrix estimator. The covariance vector estimator uses only the correlations between sensors and the pseudoinverse of the array manifold matrix estimator operates with the minimum eigenvalues of the covariance matrix. Numerical and experimental results are presented.
文摘Smoothed Particle Hydrodynamics (SPH) is fast emerging as a practically usefulcomputational simulation tool for a wide variety of engineering problems. SPH isalso gaining popularity as the back bone for fast and realistic animations in graphicsand video games. The Lagrangian and mesh-free nature of the method facilitates fastand accurate simulation of material deformation, interface capture, etc. Typically,particle-based methods would necessitate particle search and locate algorithms tobe implemented efficiently, as continuous creation of neighbor particle lists is acomputationally expensive step. Hence, it is advantageous to implement SPH, on modernmulti-core platforms with the help of High-Performance Computing (HPC) tools. Inthis work, the computational performance of an SPH algorithm is assessed on multicore Central Processing Unit (CPU) as well as massively parallel General PurposeGraphical Processing Units (GP-GPU). Parallelizing SPH faces several challenges suchas, scalability of the neighbor search process, force calculations, minimizing threaddivergence, achieving coalesced memory access patterns, balancing workload, ensuringoptimum use of computational resources, etc. While addressing some of these challenges,detailed analysis of performance metrics such as speedup, global load efficiency, globalstore efficiency, warp execution efficiency, occupancy, etc. is evaluated. The OpenMP andCompute Unified Device Architecture (CUDA) parallel programming models have beenused for parallel computing on Intel Xeon(R) E5-2630 multi-core CPU and NVIDIAQuadro M4000 and NVIDIA Tesla p100 massively parallel GPU architectures. Standardbenchmark problems from the Computational Fluid Dynamics (CFD) literature are chosen for the validation. The key concern of how to identify a suitable architecturefor mesh-less methods which essentially require heavy workload of neighbor search andevaluation of local force fields from neighbor interactions is addressed.
