Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element meth...Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element method(SPEM) to simulate FSIs. In this method, both the fluid and solid regions are initially modeled using a smoothed finite element method(S-FEM) in a Lagrangian frame, whereas the fluid regions undergoing large deformations are adaptively converted into particles and modeled with an improved smoothed particle hydrodynamics(SPH) method. This approach greatly improves computational accuracy and efficiency because of the advantages of the S-FEM in efficiently treating solid/fluid regions showing small deformations and the SPH method in effectively modeling moving interfaces. In this work, we further enhance the efficiency of the SPEM while effectively capturing local fluid information by introducing a multi-resolution technique to the SPEM and developing an effective approach to treat multi-resolution element-particle interfaces. Various numerical examples demonstrate that the multiresolution SPEM can significantly reduce the computational cost relative to the original version with a constant resolution.Moreover, the novel approach is effective in modeling various incompressible flow problems involving FSIs.展开更多
Change in the temperature of band over its length, associated with the stock being non-uniformly heated in the furnace, influences the variations in the magnitudes of energy-force parameters. Using the FEM (Finite Ele...Change in the temperature of band over its length, associated with the stock being non-uniformly heated in the furnace, influences the variations in the magnitudes of energy-force parameters. Using the FEM (Finite Element Model) programs for the computation of the values of the energy-force parameters can take into account the distribution of temperature over the band length. The mathematical model of the computer program Forge2008 was used to theoretically examine the energy-force parameters and plastic metal flow in the roughing stands of the continuous rolling mill. The results of experimental investigation of influence of the non-uniform temperature distribution were presented on the metallic charge length on the energy and force parameters and dimensions of the band during round bars rolling. Thermovision monitoring energy and force parameters monitoring were carried out in continuous rolling mill D350 in one of the Polish industrial plants. On the basis of obtained results, it could be stated that non-uniform distribution of temperatures along the charge length causes local increase of energy and force parameters values and also such distribution affects the local increase of the width of rolled band. The rolling process of charge with non-uniform distribution of temperature could lead to exceeding required dimensional tolerances of the final products.展开更多
The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solv...The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.展开更多
Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanoc...Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.展开更多
基金supported by the National Numerical Wind Tunnel Project (Grant No. NNW2019ZT2-B02)the National Natural Science Foundation of China (Grant Nos. 12032002,51779003,and 11902005)the SinoGerman Mobility Programme (Grant No. M-0210)。
文摘Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element method(SPEM) to simulate FSIs. In this method, both the fluid and solid regions are initially modeled using a smoothed finite element method(S-FEM) in a Lagrangian frame, whereas the fluid regions undergoing large deformations are adaptively converted into particles and modeled with an improved smoothed particle hydrodynamics(SPH) method. This approach greatly improves computational accuracy and efficiency because of the advantages of the S-FEM in efficiently treating solid/fluid regions showing small deformations and the SPH method in effectively modeling moving interfaces. In this work, we further enhance the efficiency of the SPEM while effectively capturing local fluid information by introducing a multi-resolution technique to the SPEM and developing an effective approach to treat multi-resolution element-particle interfaces. Various numerical examples demonstrate that the multiresolution SPEM can significantly reduce the computational cost relative to the original version with a constant resolution.Moreover, the novel approach is effective in modeling various incompressible flow problems involving FSIs.
文摘Change in the temperature of band over its length, associated with the stock being non-uniformly heated in the furnace, influences the variations in the magnitudes of energy-force parameters. Using the FEM (Finite Element Model) programs for the computation of the values of the energy-force parameters can take into account the distribution of temperature over the band length. The mathematical model of the computer program Forge2008 was used to theoretically examine the energy-force parameters and plastic metal flow in the roughing stands of the continuous rolling mill. The results of experimental investigation of influence of the non-uniform temperature distribution were presented on the metallic charge length on the energy and force parameters and dimensions of the band during round bars rolling. Thermovision monitoring energy and force parameters monitoring were carried out in continuous rolling mill D350 in one of the Polish industrial plants. On the basis of obtained results, it could be stated that non-uniform distribution of temperatures along the charge length causes local increase of energy and force parameters values and also such distribution affects the local increase of the width of rolled band. The rolling process of charge with non-uniform distribution of temperature could lead to exceeding required dimensional tolerances of the final products.
文摘The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.
文摘Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.
