加强肋结构参数对塑料井盖力学性能的影响

为研究加强肋结构参数对塑料井盖力学性能的影响,根据弹性力学理论,采用有限元方法对带肋塑料井盖受力情况进行了模拟分析,通过使用Abaqus软件对拥有不同加强肋结构参数的塑料井盖进行受力模拟,分析加强肋结构参数与塑料井盖力学性能的关系。模拟结果表明:提高肋高(h)或肋宽(b)都可以提高塑料井盖的刚度,改善其受力性能;在h80mm时,提高肋高(h)对增强塑料井盖刚度,改善其受力性能作用显著,而提高肋宽(b)的作用不明显,随着h的增大,提高肋高(h)所起到的作用减弱,相对的提高肋宽(b)所起到的作用增强,当h160mm时,提高肋高(h)所起到的作用极小,而提高肋宽(b)所起到的作用要高于提高肋高(h)所起到的作用;加强肋的最大应力高于面板的最大应力,其差值随塑料井盖受力性能的改善而减小。     

Finite Element Analysis of Shape Memory Alloy Adaptive Trusses with Geometrical Nonlinearities

This contribution deals with the nonlinear analysis of shape memory alloy (SMA) adaptive trusses employing the finite element method. Geometrical nonlinearities are incorporated into the formulation together with a constitutive model that describes different thermomechanical behaviors of SMA. It has four macroscopic phases (three variants of martensite and an austenitic phase), and considers different material properties for austenitic and martensitic phases together with thermal expansion. An iterative numerical procedure based on the operator split technique is proposed in order to deal with the nonlinearities in the constitutive formulation. This procedure is introduced into ABAQUS as a user material routine. Numerical simulations are carried out illustrating the ability of the developed model to capture the general behavior of shape memory bars. After that, it is analyzed the behavior of some adaptive trusses built with SMA actuators subjected to different thermomechanical loadings.     

不同加载角下L形柱的承载力与延性分析

采用Abaqus软件建立L形柱的三维非线性有限元模型,分析了L形柱在不同加载角下的承载力与延性,计算结果与试验值符合良好,分析表明：加载角为135°时,承载力是最大的,延性良好;加载角为225°时,承载力是最小的,延性也最差;加载角为0°时,延性是最好的。     

Bipotential versus return mapping algorithms: Implementation of non associated flow rules

Numerical implementation of constitutive laws involves specific incremental methods. The “return mapping” (Simo and Hughes, 1998) and the “bipotential” (de Saxcé, 1992) are one of those, associated respectively to two different classes of materials: the General Standard Materials (GSM) for the return mapping and the Implicit Standard Materials (ISM) for the bipotential.The objective of this paper is then to compare the implementation of those both methods in the case of non associated flow rules in plasticity.In the first section, the properties of the different previous material classes will be recalled and the methods of “return mapping” and “bipotential” will be detailed. The comparison of both methods is realised on the non linear kinematic hardening rule of Armstrong–Frederick (Armstrong and Frederick, 1966) in a second section and the details are given in a third part. The numerical implementation is realised in Abaqus/Standard 6.11 by the means of a UMat subroutine and the practical simple case of tension–compression is analysed in a last section.     

集中荷载下钢筋混凝土简支T型梁剪力滞效应

通过对钢筋混凝土简支T型梁进行两点加载试验,研究T型梁翼板内不同截面的剪力滞效应,并通过Abaqus有限元软件对T型梁的加载全过程进行模拟.试验结果表明:简支T型梁在靠近支座位置存在负剪力滞区,随着荷载增大,负剪力滞效应逐渐增强,并且负剪力滞区出现受拉现象,拉应力达到2.34 MPa,而在纯弯段,荷载的增大对剪力滞系数影响不大;T型梁翼板内的剪力主要发生在翼板和腹板交界处,剪力在向翼板边缘传递的过程中快速衰减,在翼板没有出现裂缝前,剪力滞效应随着腹板厚度的增加而降低,但是降低的程度随着腹板厚度的持续增加而减小.     

On a method of comparison for plate elements in finite element engineering software programs

The purpose of this paper is to propose a method for the evaluation of plate elements in the finite element engineering software comparatively to the Kirchhoff and Reissner plate theories. The method is based on the study of transverse deflection near a crack tip. A numerical work has been conducted for the shell elements in Abaqus software with different crack lengths and various thicknesses. The deflection can be written as a function of the exponent of the distance between the crack tip and one point along the crack. This exponent is accepted to describe the behaviour of finite elements.     

基于X—rayCT的沥青混合料三维重构方法

沥青混合料内部的细微观结构对沥青混合料的路用性能有很大的影响,很有必要开发一种可以进行沥青混合料内部结构受力状况分析的三维重构模型。基于X-rayCT技术,每隔1rrlrn获取沥青混合料试件断层图像,共64张。将控制集料、砂浆、空隙三者之间的阈值进行物质的区分。利用Matlab自编程序完成沥青混合料的三维重构,并提出了一种获取沥青砂浆黏弹性参数的方法。用该模型进行数值模拟后的试验结果与室内试验结果有很好的吻合,验证了本重构方法的正确性。     

基于Abaqus的喷管喉衬强度仿真

 应用有限元仿真软件对结构进行强度分析时,要求仿真结果与结构实际情况相符合。在对结构进行建模时,要保证模型简化方式与结构实际情况一致,以减小模型简化对仿真结果造成的影响。喷管喉衬是固体火箭发动机中的重要零件之一,在发动机工作过程中起到压缩燃气的作用,因此对喉衬进行强度仿真十分重要。本文基于Abaqus仿真计算软件,以某固体火箭发动机的喷管喉衬为例,建立喉衬的3种有限元简化模型,分别进行有限元强度计算,并对仿真结果进行对比讨论。结果表明不同的简化模型可能会对仿真结果造成重大影响。因此,在采用有限元仿真分析时,应针对具体情况进行分析,以保证计算结果的精准度。     

基于Abaqus的防滑差速器壳体静力学分析

为获得某款防滑差速器壳体在实际工况中的具体力学特性,基于有限元分析法对某四驱汽车防滑差速器壳体进行设计分析。首先,在Abaqus软件中建立防滑差速器壳体的有限元分析模型。接着,利用Romax软件进行防滑差速器壳体在两种极限工况下的轴承受力分析,同时设立更为精确的边界条件和载荷,从而进行应力、应变和疲劳分析。分析结果表明该防滑差速器壳体在极限工况下位移量较大,需要进行优化设计。结合静力学分析结果,以壳体加强筋的长度和厚度为优化变量,对防滑差速器壳体进行优化设计,通过优化前后对比分析,发现优化后壳体在各种工况下的应力和应变均显著降低,符合设计要求。采用软件仿真进行轴承受力分析有效地避免了繁琐的理论计算,同时使得分析方法更加简单,分析结果更贴合实际。另外,有限元分析方法也大幅缩短了防滑差速器壳体的研发周期与设计成本。     

美国某洲际大桥桥梁结构的有限元分析

采用Python面向对象语言来进行二次开发的应用,计算平台采用著名的Simulia Abaqus,本文主要讨论Abaqus脚本接口和对象结构逻辑化在开发中的优势,把工业模拟计算平台再次模块化可以减少重复逻辑的调用,流程更清晰、简明,应用更方便,提高效率.