基于热机械劳分析的排气歧管优化设计

The Optimization Design of Exhaust Manifold Based on Thermo Mechanical Fatigue Analysis

联合AVL-Fire和ABAQUS软件,对某直喷汽油机进行排气歧管热机械疲劳分析。首先利用AVL-Fire软件得到排气歧管在全速全负荷工况、倒拖工况和怠速工况下的内外表面热边界条件,映射到有限元单元上进行耦合计算,得到相应工况下的温度场以及应力场分布,并通过热机械循环计算排气歧管的累积塑性应变,判断排气歧管是否会发生低周疲劳断裂。并根据分析结果对排气歧管进行优化设计,结果表明此方法可以很好的应用在排气歧管优化设计上。

combined with AVL-Fire and ABAQUS software,analyzed the exhaust manifold thermal mechanical fatigue of a direct injection gasoline engine.First get the exhaust manifold in full load condition,dragged inside and outside surface thermal boundary condition condition and under idling condition by using AVL-Fire software,mapping to the finite element on the coupling calculation of temperature field,obtained the corresponding conditions and stress field distribution,accumulation and exhaust manifold by thermomechanical cycle plastic strain,to judge whether the exhaust manifold of low cycle fatigue fracture.And according to the results of the analysis to optimize the design of the exhaust manifold,the results show that this method can be well applied in the exhaust manifold optimization design.