多孔高聚物力—热耦合响应特性研究

发布时间：2018-03-20 09:09

本文选题：多孔聚合物　切入点：应变率效应　出处：《西南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文主要研究了多孔聚合物在多因素下的静动态力学性能和力-热耦合响应特性。具体的研究内容如下:1、利用三维数字散斑动态变形测量分析技术联合材料试验机对硬质聚氨酯泡沫塑料RPUR和泡沫硅橡胶SR进行准静态拉伸、压缩实验,获得其在不同应变率、不同取样方向、不同温度等条件下的力热响应特性。实验结果表明:RPUR材料和SR材料在拉伸和压缩实验中都具有不太显著的应变率效应及一定的温度效应,压缩试验中的温度敏感性要强于拉伸试验中的温度敏感性,高密度RPUR对温度的敏感性强于低密度RPUR的温度敏感性,且其拉伸强度和屈服应力随温度的升高而降低;拉伸试验和压缩试验中试件力学性能都表现为各向异性。SR压缩实验中试件尺寸的不同对研究其力学性能几乎没有影响;RPUR压缩试件尺寸的不同对材料的力学行为有显著影响。拉伸试验中SR试件因泡孔壁沟槽的产生而破坏,压缩试验中试件由于泡孔受力压溃而出现裂痕;拉伸试验中RPUR泡孔有明显的裂纹,压缩试验中试件由于泡孔受力完全变形而彻底破坏。2、利用加长式分离式霍普金森杆(SHPB)研究RPU R和SR泡沫材料在高应变率条件下的动态力学性能。发现RPUR和SR材料的动态力学性能不同于静态力学性能,其在研究的高应变率范围内应变率效应都不太明显;而动态与静态条件下的力学性能相比则有明显的应变率相关性。3、在准静态试验过程中试件内部温度在破坏时达到最高,试件不同位置处的温度变化情况基本一致。SR的最大温升较小,可视为是等温实验;而RPUR的温升较大,且升热速率和最大温升随加载速率的增大而增大。
[Abstract]:In this paper, the static and dynamic mechanical properties of porous polymers under multi-factors and the mechanical-thermal coupling response characteristics are studied. The specific contents of the study are as follows: 1. The three-dimensional digital speckle dynamic deformation measurement and analysis technique is used to test the materials. The machine carried out quasi static stretching of rigid polyurethane foam RPUR and silicone rubber foam SR. Compression experiments were performed to obtain different strain rates and different sampling directions. The experimental results show that the strain rate effect and temperature effect of both the W RPUR material and the SR material are not obvious in the tensile and compression tests. The temperature sensitivity of compression test is stronger than that of tensile test. The temperature sensitivity of high density RPUR is stronger than that of low density RPUR, and the tensile strength and yield stress decrease with the increase of temperature. The mechanical properties of the specimens in tensile test and compression test are anisotropic. The difference of specimen size in SR compression test has little effect on the mechanical properties of the material. The mechanical behavior of the material is similar to that of the RPUR compression specimen. Significant effect. In tensile test, SR specimen was destroyed by the formation of bubble hole wall grooves, In the compression test, cracks appeared in the specimens due to the bursting of the bubble holes, while in the tensile tests, there were obvious cracks in the RPUR bubble pores. In the compression test, the specimen was completely destroyed because of the complete deformation of the bubble hole. The dynamic mechanical properties of RPUR and SR foam materials under high strain rate were studied by using the extended split Hopkinson rod SHPB. it was found that the RPUR and SR materials were subjected to high strain rate. The dynamic mechanical properties of the system are different from those of the static mechanical properties, In the range of high strain rate studied, the strain rate effect is not obvious, but the dynamic and static mechanical properties have obvious strain rate correlation. The internal temperature of the specimen reaches the highest in the process of quasi-static test. The maximum temperature rise of SR is small, which can be regarded as isothermal experiment, but the temperature rise of RPUR is larger, and the heating rate and maximum temperature rise increase with the increase of loading rate.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB324

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