船用柴油机缸盖缩尺试样的热失效研究  

Study on Thermal Failure of Marine Diesel Engine Cylinder Head Scale Specimen

作　　者：梁刚 张华兵 张国勇 李丽婷 崔毅[3] LIANG Gang;ZHANG Huabing;ZHANG Guoyong;LI Liting;CUI Yi(Shanghai Marine Diesel Engine Research Institute,Shanghai 201108,China;National Engineering Research Center of Special Equipment and Power Systems for Ship and Marine Engineering,Shanghai 201108,China;School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]中国船舶集团有限公司第七一一研究所,上海201108 [2]船舶与海洋工程特种装备和动力系统国家工程研究中心,上海201108 [3]上海交通大学机械与动力工程学院,上海200240

出　　处：《内燃机工程》2024年第3期86-94,101,共10页Chinese Internal Combustion Engine Engineering

摘　　要：为研究船用柴油机缸盖在低周热循环载荷下的渐进失效问题,开展了“四孔平板”缩尺试样的热失效模拟试验,建立了基于温度依赖的Chaboche组合硬化材料模型和改进Ostergren塑性能量损伤模型的仿真方法,研究了塑性变形演化、疲劳开裂的热失效行为和机理。研究表明:仿真预测具有较高精度,圆孔失圆变形预测最大偏差不超过10.5%,准确预测了裂纹的萌生位置,预测寿命与实际失效循环数目接近;缩尺试样受到循环变化的温度梯度影响,整体结构表现为热弯曲变形失配,产生的局部非对称拉压应力引发了塑性变形;随着循环次数增加发生应力松弛,塑性变形呈现先快后慢的非线性减少趋势;冷却阶段的拉伸塑性应变能和应力三轴度增加,引发了圆孔鼻梁高应力区开裂损坏。To investigate the progressive failure in marine diesel engine cylinder heads under low-cycle thermal cycling loads,a simulation experiment using a“four-hole plate”scale specimen was conducted.A simulation method based on the temperature dependent Chaboche combined hardening material model and an improved Ostergren plastic energy damage model were utilized to analyze the thermal failure behavior and the mechanism of plastic deformation and thermal fatigue cracking.The research findings demonstrate high accuracy in the simulation predictions with a maximum deviation of 10.5%for predicting out-of-round deformation of circular holes.Additionally,the crack initiation position was accurately predicted,and the predicted life was close to the actual failure cycle number.Cyclic temperature gradients influence the scale specimen,resulting in mismatched thermal bending deformation across the entire structure and causing local asymmetric tensile and compressive stresses that induce plastic deformation.With increasing cycles,stress relaxation occurs,and plastic deformation decreases non-linearly from fast to slow.The cracking and damage of the high-stress region of the round hole bridge are attributed to the increase in tensile plastic strain energy and stress triaxiality during the cooling stage.

关 键 词：船用柴油机 缸盖 缩尺试样 材料模型 数值仿真 热失效机理 

分 类 号：TK423[动力工程及工程热物理—动力机械及工程]