夹芯复合材料板架强度试验及典型节点疲劳试验验证研究

Strength test of sandwich composite structure and fatigue life study of typical bolted joints

  • 摘要:
    目的 夹芯复合材料在船舶结构中的应用日益广泛,为保证结构的强度特性,夹芯复合材料结构与钢质主船体之间通常采用螺栓连接,但由于孔周围的局部应力集中及连接位置的边界效应,螺栓连接位置通常为结构最危险的位置,需要进行强度及疲劳校核。
    方法 针对一实尺度钢–夹芯复合材料板架结构,通过试验方法和有限元方法对板架在0.1 MPa均布载荷作用下的强度特性进行研究。通过对比试验测量与有限元计算的结果验证有限元方法的计算精度。基于有限元方法,通过结构应力等效的方式,设计两个等效疲劳试验节点,通过试验方法对钢–夹芯复合材料结构的疲劳寿命进行考核验证。
    结果 研究发现,该板架结构在设计载荷下的疲劳寿命满足500万次循环的设计要求。
    结论 对于大型螺栓连接结构的疲劳问题,可设计等效节点进行疲劳试验,通过结构应力等效的方式进行载荷等效。

     

    Abstract:
    Objectives In the application of sandwich composite materials in ship structures, to ensure the structural strength characteristics, bolt connections are usually used between the sandwich composite structure and steel main hull. However, due to local stress concentration around the holes and the boundary effects at the connection locations, the bolt connection position is often becomes the most critical area of the structure, necessitating strength and fatigue assessments.
    Methods For a full-scale steel-sandwich composite panel structure, the strength characteristics of the plate frame under a 0.1 MPa uniform load are studied using experimental and finite element methods. The accuracy of the finite element method is then verified by comparing its results with those from the experimental method. Subsequently, based on the finite element method, fatigue tests for two equivalent bolted joints are designed through structural stress equivalence, and the fatigue life of the steel-sandwich composite structure is evaluated and verified.
    Results It is determined that the fatigue life of the panel structure under the design load meets the design requirement of 5 million cycles.
    Conclusions Regarding the fatigue problem of large bolted connections, equivalent joints can be designed for fatigue testing, and load equivalence can be achieved through structural stress equivalence.

     

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