孔隙率对2D-FGM板瞬态热应力的影响

发布时间：2018-01-12 10:24

本文关键词：孔隙率对2D-FGM板瞬态热应力的影响　出处：《河北工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：21世纪,功能梯度材料(Functionally Graded Matiral,简称FGM)已凭借其耐热冲击性、导电绝缘双重性、生物相容性等诸多优良特性得到了国内外学者高度重视,并在航空航天、光电工程、生物医学等领域得以广泛的应用。本文基于有限元法对常物性Ti-6Al-4V、Al 1100和ZrO2三种材料组成的2D-FGM矩形平板进行研究。首先应用了加权余量法和传热学的相关公式推导得到有限单元法的基本方程,通过FORTRAN计算机语言编写的网格自动划分程序和应力场有限元计算程序计算得到研究模型的热应力分布；然后,将有限元法得到的近似解与数学解析值法得到的解析解进行误差分析,说明了本文采用的有限元法是完全正确的；最后分析了不同孔隙率控制参数下的常物性2D-FGM矩形平板在第一类加热边界条件下,单侧加热、两侧加热与四周加热三种情况下的瞬态热应力分布规律。2D-FGM矩形平板瞬态热应力分布表明：当结构的单侧边界加热函数设置为常数函数时,同一时刻下板内的热应力分布随Ax取值的增大,在靠近轴y=y/b=0附近区域的应力分布曲线与轴y:y/b=0的角度变小；但随Ax取值的变化,其应力分布的变化并不明显；研究t=1.0s时刻,固定Ax=0.0不变,Ay=3.0的最大热应力绝对值比Ay=1.0的减小了8.91%,最小热应力绝对值增大了274.23%；而Ay=0.0固定不变,Ax=3.0的最大热应力绝对值比Ax=1.0仅增大了0.08%,最小热应力绝对值增大了65.92%,数据说明沿板厚度方向的孔隙率控制参数Ay对加热热应力的影响比沿板长度方向的孔隙率控制参数Ax的影响更为明显；研究模型的结构几何形状及边界条件均关于轴x=x/α=0.5对称,但其应力场表现为非对称分布且上边界受到的应力绝对值最大；当结构的边界为其它加热函数时,改变孔隙率控制参数导致热应力变化的规律基本一致,说明外界热荷载的施加形式对热应力场影响并不明显。本文主要分析孔隙率对该矩形板加热瞬态热应力分布的影响,上述分析结果对设计和优化2D-FGM矩形平板的孔隙率有着一定的参考意义。
[Abstract]:In twenty-first Century, functional gradient materials (Functionally Graded Matiral, referred to as FGM) by virtue of its thermal shock resistance, conductive insulation dual, biocompatibility of many excellent properties such as by domestic and foreign scholars attach great importance, and Optoelectronic Engineering in aerospace, biomedical and other fields, has been widely used. This paper based on the finite element method of constant physical Ti-6Al-4V, 2D-FGM and ZrO2 1100 Al rectangular plate composed of three kinds of materials were studied. The basic equations of the first application of the formula is derived by the method of weighted residuals and heat transfer by the finite element method, the grid FORTRAN computer language automatic division of the program and the stress field of finite element program to calculate the thermal stress of model then, the obtained stress distribution; finite element method analytical approximate solution method to get the solution of error analysis and mathematical analysis, the paper use the finite element method Is completely correct; finally analyzes the different porosity control parameters often 2D-FGM rectangular plate in the first heating heating boundary conditions, unilateral, transient thermal heating and heating on both sides around three cases of stress distribution of.2D-FGM rectangular transient thermal stress distribution showed that when the unilateral boundary heating function structure set to a constant function at the same time in the distribution of the thermal stress increases with the value of Ax, in the region near the near axis y=y/b=0 stress distribution curve and the y:y/b=0 axis angle became smaller; but the change with the Ax values, the change of stress distribution is not obvious; on time t=1.0s, fixed Ax=0.0 the same, the maximum thermal stress of the Ay=3.0 absolute value is reduced by 8.91% Ay=1.0, the minimum thermal stress increases the absolute value of 274.23%; while the Ay=0.0 is fixed, the maximum thermal stress of the Ax=3.0 than the absolute value of Ax=1.0 is increased by 0 .08%, the minimum thermal stress increases the absolute value of 65.92%, data shows that the effect of porosity along the thickness direction of the heating control parameters of Ay thermal stress along the length direction of the plate than the porosity control parameters of Ax was more obvious; geometry and boundary conditions of the model are on axis x=x/ alpha =0.5 symmetry, but its the stress field by asymmetric distribution and stress on the boundary of the absolute value of the maximum; when the structure boundary for other heating function, change the control parameters lead to thermal stress change of porosity should be similar, that imposed form of external heat load on the thermal stress field effect is not obvious. This paper mainly analyzes the porosity should be the effect of pressure distribution on the transient thermal heating of the rectangular plate, the results of the design and optimization of 2D-FGM rectangular plate porosity has a certain reference value.

【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

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