摘要机体是发动机中最重要的零部件之一,它的强度和动态特征是保证发动机能够正 常工作的前提。机体强度指标的不断提高，使得它的热负荷和机械负荷不断增加，设 计与制造上稍有失误就可能使机体在工作状态下出现裂纹等破坏现象，从这种层面上 来说，机体是直接影响到发动机整机可靠性的关键零部件。因此，对柴油机机体进行 动态特征研究，表示出外界激振力与结构固有特性之间的关系具有非常重要的意义。 有限元分析法是一种可通用的数值分析方法，它是目前研究复杂结构的受力问题最有 效和可靠的手段。84101

本文以某四缸柴油机机体为实例，使用有限元分析 ANSYS 软件对其进行了详细的 研究分析。先是分析柴油机机体图纸，通过 Pro/E 软件对机体进行建模工作，并且进 行适当的简化。将模型导入 ANSYS 软件，对机体实体模型进行智能网格的划分，建立 了有限元模型。其次，考虑柴油机的稳定工作状况，以活塞连杆机构运动的往复惯性 力、气缸内燃气压力、活塞侧压力为主要因素，确定机体所受的激励力。计算出了柴 油机机体四缸的活塞侧向力、主轴承载荷以及螺栓轴向载荷；提出了以上载荷在 ANSYS 软件中的加载方法，为确保对有限元模型和有限元分析中的载荷进行精确的载 荷。

最后，对该柴油机机体进行应力计算，并根据计算结果对机体进行了强度校核， 分析结果对机体的设计和结构的优化具有很重要的意义。

毕业论文关键词：柴油机机体；Pro/E；ANSYS；强度校核；

Abstract Engine body skeleton, is the basis of the working mechanism of the engine, subjected to various loads of the engine, only part of the body has a sufficiently high stiffness and strength in order to ensure proper operation of the various components of the engine can be prolonged。 Increase now the body heat load and mechanical load, mainly because the body strength index rising。 So in the design and manufacturing process if there is a little mistake, it can allow the body to produce damage in the operation state。 From this, the body has an important impact on the entire life of the engine of the machine。 So you want to work out the inherent characteristics associated with both the outside world and the exciting force structure, need to study the dynamic characteristics of diesel engine block, this study has very important significance。 Finite element analysis is a kind of common numerical analysis method, finite element analysis on the current complex structure of the question of admissibility is the most effective and reliable method。

Taking a four-cylinder engine block as an example, the use of finite element analysis software ANSYS was carried out detailed research and analysis。 Firstly, the analysis of diesel engine block drawings, Pro/E software for modeling work on the block through three-dimensional modeling, and appropriate simplification。 The model into ANSYS software, and the three-dimensional solid model of the block has been pided manual grid, the finite element model is established。 Secondly, considering the  stable working conditions of diesel engine, to motion of piston linkage mechanism of reciprocating inertia force, gas pressure in cylinder, piston side pressure is the main factor determined body by the exciting force。 Diesel engine four cylinder piston lateral force are calculated, spindle bearing and bolt axial load; put forward the above load in ANSYS software loading method, to ensure that the load precise load to the body of the finite element model and of the finite element analysis。

Finally, the diesel engine block stress and deformation calculation, based on the results  carried  out  on  the  engine  block  strength  check,  the  results  have       important