加筋板低周疲劳寿命和累积塑性应变模型  

The low-cycle fatigue life model and the accumulative plastic strain model for stiffened plates under cyclic loading

作　　者：汪丹[1] 杨平[1,2] 邓军林 董琴[1] 

机构地区：[1]武汉理工大学交通学院,湖北武汉430063 [2]武汉理工大学高性能舰船技术教育部重点实验室,湖北武汉430063

出　　处：《中国舰船研究》2015年第6期39-44,共6页Chinese Journal of Ship Research

基　　金：国家自然科学基金面上项目(51479153);中央高校基本科研业务费专项资金资助项目(2015-yb-004)

摘　　要：为分析加筋板结构累积塑性破坏的影响,应用损伤力学基础理论,并结合筋板相互影响系数,以塑性应变为损伤演化的控制参量,推导并建立加筋板结构低周疲劳累积递增塑性应变模型和低周疲劳寿命模型。将加筋板在循环载荷下的疲劳损伤变量引入累积递增塑性应变方程中,通过积分变换,推导出循环载荷下船舶加筋板结构轴向累积塑性应变的演化方程及其低周疲劳寿命本构模型;采用船舶通用高强度402钢相关材料疲劳特性参数对船舶加筋板结构低周疲劳寿命模型进行对比分析;将塑性应变发展理论模型与有限元计算结果进行比较,分析平均应力和筋条刚度比对累积塑性应变的影响规律。结果表明,该模型较好地反映了船舶加筋板结构的轴向累积塑性应变演化规律,同时能方便地对船舶结构低周疲劳强度进行评估、校核。In order to analyze the increasing accumulative plastic damage of ship stiffened plates, this paper combines the interaction coefficients of stiffeners and plates, and with plastic strain of damage evolution being the control parameter, the low-cycle fatigue accumulative increasing plastic damage model and low-cycle fatigue life model for stiffened plates have been derived based on the theory of damage mechanics. The fatigue damage variable of the stiffened plate under cyclic loading is then introduced into the accumulative plastic strain equation. Next, by means of integral transformation, the evolution equation of axial accumulative plastic strain and the constitutive model for low-cycle fatigue life are deduced under low cyclic loading. The general high strength steel 402 is adopted, with its related material fatigue characteristic parameters introduced to be compared with the low-cycle fatigue life model of stiffened plates. The theoretical evolution results from the presented models of the accumulative plastic strain damage are compared with finite element modeling results, and the influences of mean stress and rib stiffness ratio on the accumulated plastic strain are discussed. The results indicate that the established model well reflects the evolutional law of the axial plastic strain of the stiffened plate under cyclic loading and brings convenience into the evaluation of low-cycle fatigue strength of ship structures.

关 键 词：损伤力学 加筋板 低周疲劳 累积塑性应变 

分 类 号：U661.41[交通运输工程—船舶及航道工程]