发动机气缸体螺纹联接强度有限元分析

FEA of screw thread connection strength in engine cylinder block

针对发动机设计中螺纹联接强度计算的问题,采用有限元通用程序ABAQU S/STANDARD,研究气缸体螺纹区域强度准确计算的方案,即通过简化后的装配体模型计算螺栓在工作载荷下的受力,然后将获得的螺栓受力做为载荷边界条件施加在带螺纹的局部模型中,计算螺栓和缸体螺纹区域的应力.网格划分时,在局部模型中将缸体简化,并将螺柱分为两部分,之后皆用六面体单元进行网格划分以减小计算量、提高准确性.最后通过实例对某气缸体螺纹区域在预紧状态、峰值燃烧压力作用下的应力进行计算与分析,验证该计算方案的可行性.该方案为今后发动机的螺纹联接设计和计算提供一条可行的路径,且对相关的工程实际应用具有很强的指导意义.

Aiming at the calculating problem of screw thread connection strength in engine design, by adopting FEA application ABAQUS/STANDARD, a scheme for accurately computing strength of screw thread area in cylinder block is studied, which means to compute bolt bearing forces under working load through simplified assembly model. The acquired bolt bearing force, regarded as load distribution, will be applied to the local model with thread to compute the thread stress distribution around the bolt and cylinder block. In meshing scheme, the simplified cylinder block and bolt, divided into two parts in local model, were meshed by hexahedral elements to save computation cost and improve computation accuracy. Finally, stress distribution for thread in engine cylinder block in pre-tension load case and peak-combustion-pressure load case are calculated and analyzed to verify this method. It provides a way for design and calculation of thread connection in engines and gives reference to the practical application of related project.