基于流固耦合分析某排气歧管疲劳损伤

摘要

研究某柴油机排气歧管在可靠性实验中出现开裂故障，通过建立排气歧管内流场CFD模型和管壁有限元模型进行流固耦合分析。结果表明：由于排气歧管的内部对流换热和管壁内部导热的作用，排气歧管管壁存在较大的温度，并受到边界约束产生集中应力导致歧管的开裂。通过仿真获得排气歧管发生等效塑性应变，并通过M-C公式可分析排气歧管的疲劳寿命。%The cracking failure of the exhaust manifold of a diesel engine was studied. The CFD model and the finite element model of the tube wall were analyzed by establishing the model of the flow field in the exhaust manifold. The results show that the temperature of the exhaust manifold is due to the internal heat conduction of the exhaust manifold, and the wall of the exhaust manifold has a large temperature, which is caused by the boundary constraints. The equivalent plastic strain of the exhaust manifold is obtained by simulation, and the fatigue life of the exhaust manifold can be analyzed by M-C formula.