基于模型试验的层状结构物层底应变分析

发布时间：2018-03-20 17:29

本文选题：层状结构　切入点：层底应变　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：路面是典型的层状结构物，各层厚度和强度的调整可以影响到路面的使用性能和寿命长短，长寿命路面设计的控制指标之一是面层底部拉应变，而且各国都在尝试以层底拉应变作为控制指标设计路面。因此，对结构层底拉应变的影响因素进行研究具有很好的现实意义，可以为层状结构设计尤其是道路设计提供参考。道路现场原型试验有很多难题，比如试验耗时、耗资大，试验干扰因素多，对尚未建造的工程无法进行试验，试验结果不利于推广等等。因此，，本论文用模型试验的方法分析层状结构物各层厚度、模量以及荷载、层间接触状态对层底拉应变的影响情况，明确各因素改变时层状结构物各层底应变变化规律。试验中用贴于各层底面的电阻应变计作为应变传感器，用数据信息采集仪DT85G采集不同层状结构试件的各层层底拉应变。本论文同时用ANSYS有限元法对层状结构层底拉应变进行数值模拟计算，将有限元法计算结果与试验法的检测结果进行比较。得出的主要结论有：各层底部纵向应变都大于横向应变；要减小各层底应变，单纯通过改变面层模量的方法难以达到预想的效果，适当提高面层模量的基础上增大面层厚度可以获得很好的效果；连续接触状态下的各层底应变都小于光滑接触状态下的应变；动载时层间接触状态差异对各层底的应变影响较静载时更大；加强层间处置技术，改善层间接触条件可以显著地减小各层底部拉应变。ANSYS有限元计算结果与试验结果基本吻合，可借助有限元建模分析计算进一步确定的模量和厚度对结构层底应变的影响规律。
[Abstract]:Pavement is a typical layered structure. The adjustment of the thickness and strength of each layer can affect the performance and life of the pavement. One of the control indexes in the design of long life pavement is the tensile strain at the bottom of the pavement. Therefore, it is of great practical significance to study the influencing factors of the tensile strain on the bottom of the structure, which can provide a reference for the design of layered structure, especially for the road design. There are many difficult problems in road field prototype test, such as time consuming, high cost, many interference factors, the unbuilt project can not be tested, the test result is not good for popularization and so on. In this paper, the influence of layer thickness, modulus and load, interlayer contact state on the tensile strain of layered structure is analyzed by model test. The strain change law of each layer bottom of layered structure is determined when the factors change. The resistance strain gauge attached to the bottom of each layer is used as strain sensor in the test. In this paper, the tensile strain of different layered structures is collected by DT85G, and the tensile strain of layered structure is numerically simulated by ANSYS finite element method. The result of finite element method is compared with that of test method. The main conclusions are as follows: the longitudinal strain at the bottom of each layer is greater than the transverse strain, and to reduce the strain at the bottom of each layer, it is difficult to achieve the desired effect simply by changing the modulus of the surface layer. Increasing the thickness of the surface layer on the basis of properly increasing the modulus of the surface layer can obtain good results, and the bottom strain of each layer in the continuous contact state is smaller than the strain in the smooth contact state. The difference of contact state between layers during dynamic load has a greater effect on the strain of each layer bottom than that under static load, and the finite element calculation results of the finite element method can significantly reduce the tensile strain at the bottom of each layer by strengthening the interlayer disposal technology and improving the contact condition between the layers. The results of finite element analysis are in good agreement with the experimental results. The influence of modulus and thickness on the bottom strain of structure can be calculated by means of finite element modeling.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.03

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