球状飞射物对屋面瓦片冲击效应的数值模拟

Numerical Simulation of Impact Effect of Windborne Spherical Debris on Roof Tiles

摘要:

选取典型的球状混凝土飞射物，研究其对一种典型屋面陶土瓦片的冲击破坏作用.基于ANSYS/LSDYNA平台，参考落球冲击试验方法建立冲击碰撞的有限元计算模型.选取JohnsonHolmquistCeramic本构模型模拟陶土瓦片材料，引入单元应变失效准则模拟瓦片破坏情况，采用显式动力学方法研究落球冲击试验中瓦片应力、应变、变形的时变机理.对冲击速度、球块质量、瓦片倾角进行参数分析，结果表明,瓦片最大等效应力与冲击速率及球块质量大致成正比，与瓦片倾角相关性不大.冲击过程是一个能量显著转移的过程，根据损伤方程计算出陶土瓦片能承受不超过34.35 m?s-1的来流风速下球状混凝土飞射物的冲击破坏作用.

关键词:屋面瓦片; 球状飞射物; 冲击效应; 数值模拟

Abstract:

A typical spherical concrete flying object was selected to study its impact effect on a typical roof clay tile. Based on ANSYS/LSDYNA and dropball impact experiment, a finite element model was established to study the impact effect of windborne spherical concrete debris on a clay roof tile. The JohnsonHolmquistCeramic constitutive model was chosen to simulate the mechanical properties of clay roof tiles, the element strain failure criteria were introduced to simulate the breakage of tile, and the explicit dynamic algorithm was used to study the time history of the tile stress, strain and deformation during the dropball experiment. The impact effect of tile inclination angle, sphere impact velocity and mass were analyzed. The results show that the maximum von mises stress of the tile is approximately proportional to both the impact velocity and the sphere mass. By contrast, the stress is unrelated to the tile inclination angle. The energy transfer during the process of impacting was remarkable, and the clay roof tile can endure the impact effect of the spherical concrete debris when the wind speed is less than 34.35 m?s-1 according to the function.

Key words:roof tiles; sphere debris; impact effect; numerical simulation