| 摘要:针对某船用单缸柴油机排气管在试验过程中出现开裂的问题，采用有限元方法，考虑材料的非线性因素,对排气管部件进行约束模态计算及热机耦合和振动疲劳计算，分析引起排气管开裂的主要原因。结果表明:排气管开裂位置受温度梯度影响,处于应力集中的薄弱区域，当振动幅度较大时，安全系数过小，易发生疲劳破坏。通过在管接部件上增加支撑提高刚度，减小排气管振动，避免了排气管疲劳开裂。后续试验验证了改进措施有效。 |
| 关键词: 单缸机 排气管 开裂 有限元分析 |
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| FEA Analysis and Optimization Method of the Cracking on ExhaustPipes of a Single-Cylinder Diesel Engine |
| Miao Weichi,Chen Lijun,Zhang Huabing,Li Liting,Tang Yihu |
| Shanghai Marine Diesel Engine Research Institute，Shanghai 201108;Power Equipment Bureau,Naval Equipment Department,Beijing 100037 |
| Abstract:A single-cylinder diesel engine met with cracking problem in its exhaust pipes during endurance test. To solve this problem, taking material nonlinear factors into considerations, FEA simulation method was employed to carry out constraint modal analysis, thermal mechanical co-simulation and vibration fatigue calculation on exhaust pipes, in order to find out the causes of those cracks. The calculation result shows that the crack position is influenced by the temperature gradient, which is the stress concentrative area. With the increase of vibration amplitude, the safety factor is too small, and it's easier to cause fatigue failure. Adding a support bracket on the pipe is efficient to improve the stiffness and reduce vibration, thus could avoid fatigue cracks on exhaust pipes. The follow-up test verified the effectivity of this improvement method. |
| Key words: single-cylinder engine exhaust pipe cracking FEA |
