Papers by Keyword: LS-DYNA

Abstract: According to the theory of collapse numerical simulation, the explicit finite element algorithm based on explicit dynamics was chose as the numerical calculation method. And combined with the plane RC frame collapse test and the example of ten layers frame structure, the wire frame model, integrated model and separate model were established and the alternate path method was adopted to study the simulate method of structural collapse. With the comparison of several aspects to the results, the rationality of the numerical simulation method and the applicability of the numerical models were verified respectively. At the same time, according to the complex pre-treatment process to the numerical simulation of structural collapse, an MFC program with the function of exporting APDL file which can generate wireframe models for structural collapse simulation in ANSYS/LS-DYNA was developed using VC++ language with the purpose of offering convenience to the numerical simulation process of structure collapse.

Abstract: The article presents calculations of fatigue life acc. to CDM model performed analytically and in program LS-DYNA with the model implemented there. On the basis of comparison of the obtained results with experimental fatigue lives, the possibility of estimation of fatigue life in LS-DYNA program acc. to CDM model was evaluated.

Abstract: Springback is a problem that must be solved in multi-point forming in this paper, finite element software ls-dyna was used to simulate plate stamping springback. 3mm thick elastic cushion inhibited dimple of sheet forming, but the use of elastic cushion and plate springback would lead to shape error. A method was proposed which modified the forming surface of element group in the Multi-point forming (MPF) by iterative ways according to the numerical simulation results. The accuracy of forming was improved after two compensation, it was proved that this method can compensate springback of the multi-point forming.

Abstract: The stress nephogram was obtained through analyzing the stress of die using the finite element software. Cause of die crack is determined from the stress nephogram, and repair plan is presented. The repair plan is analyzed by finite element and is validated by experiment.

Abstract: The broken-explosive warhead for back deep underground target and airport runway hard target has a unique advantage. Through analyzing hard target characteristics of the concrete , process using ANSYS/LS-DYNA software to break-explosive warhead of a warhead forming process and penetration into concrete target is studied by numerical simulation. Experiments show: the simulation results are accurate. A warhead on concrete penetration and expanding role better, open a channel for level two warhead implement efficient damage. To counter this deep underground and airport target road of hard target penetration has a certain application prospect.

Abstract: The present paper analyzes the phenomenon on spallation and failure of driven pile. Based on the nonlinear program LS-DYNA, the dynamical performance of driven pile into the soft soil foundation is studied by numerical simulation. Taking into account the stress-wave theory, some analyses are conducted to discuss the influence factors on spallation and failure of driven pile. The analysis results show that the compression and tension of stress wave plays an important role in the process of pile driven. Some guidance and reference is useful for the design, manufacturing and construction of piles.

Abstract: To study the tooth load distribution, the stress,strength and other issues of the non-backlash double-roller enveloping hourglass worm(NDEHW) drive, a innovative method based on finite element method and LS-DYNA software is used to do dynamic force simulation analysis.The results show that the worm gearing has good transmission performance and engagement performance, the strength and stiffness of the worm gearing does meet the design requirements. All of these work will provid a theoretical foundation and practical experience for actual design and manufacture.

Abstract: The drifting ice sheets impact with the bridge pier and other hydraulic structures in the rivers, which may damage even cause collapse of the structures. In this paper, the FEM software package LS-DYNA was used to performed the numerical simulations of the collision process of the ice sheets and the bridge piers to make clear the interaction between them and to understand the failure mechanism of the ice sheet. The elastic strain-stress model with von mises failure criterion was used to describe the ice material. The brittle damage material model was used to describe the concrete pier. Three types thickness of ice sheets were performed at various velocity of the ice sheet respectively. The impact process of every case were displayed and the time history curve of the collision force were given out. The simulations results show that the peak value of the collision force time history curve increases with the velocity of the sheet firstly and then decreases with the velocity of the ice sheet. There is one critical velocity which relate to the compressive strength of the ice sheet. The simulation result were also compared with the different bridge design code, which show that the code result is more conservative in bridge design.

Abstract: Multi-material ALE method combines the advantages of Lagrangian and Eulerian methods, avoids mesh distortion of the Lagrangian method, and eliminates moving boundary problems of the Euler method. A numerical simulation of blast-induced craters in geotechnical medium was performed within the frame of LS-DYNA by multi-material ALE method. The simulated crater which coincides with the empirical data from CONWEP was observed in post processing by the flow of material. This demonstrates that the multi-material ALE method is an effective way to simulate blast-induced craters in geotechnical medium.

Abstract: A nonlinear dynamic finite element method based on ANSYS/LS-DYNA is used to simulate the physical process of a bullet penetrating circular sandwich plate at a speed of about 400 m/s. In the simulation, Lagrange algorithm, Johnson-Cook and Crushable-foam constitutive model are choosed. Energy time history curve, impact force time history curve, Von-Mises stress nephogram and displacement nephogram are obtained. At the same time, stress time history curve of the maximum stress element and displacement time history curve of the maximum displacement node are obtained. Compared with the non-sandwich plate, it is found that the use of sandwich plate can reduce the total mass, inner plate stress and displacement, and can protect inner plate well.