Dynamic behaviour of precracked bimaterial structures applicable to wind propellers

该建议的动机是在层状复合材料（LCM）和结构，特别是双材料结构的动态断裂过程评估。预期的分析有应用的工程设计和监测知识为基础的系统的LCM（例如涡轮机和风力推进器上的薄涂层），满足对高强度、高韧性的日益增长的需求，以及与界面分层的临界长度、改变裂纹方向的能量条件、结构完全退化的临界机械载荷有关的问题，耐腐蚀性和耐磨性，并最终在制造和服务过程中降低故障率。 该项目的主要目的是开发和验证由申请人Ivanova、Becker等人（2010年）提出的分析模型，用于解决双材料结构中的动态界面内聚行为和分层。已经考虑了弹脆性界面行为。为了完成的问题，这些调查必须继续进行，并针对内聚界面行为和各自的分层。将所获得的结果应用于涡轮机和风力螺旋桨是该提案的目标之一。 解析解方法是基于改进的动态剪切滞后法，选择找到沿界面的脱粘长度沿着，并预测作为风力推进器的一部分的双材料结构的承载能力。剪滞法由于其简单性（一维模型）而非常有效。Ivanova等人（2009年）证明了其在静态情况下的成功应用。 将进行模拟研究，以评估这样的重要影响：双材料结构的几何形状，界面的弹性和内聚行为，频率和振幅的外部载荷对脱粘长度的影响，以及结构的安全区。

The proposal is motivated by the dynamic fracture process evaluation in layered composite materials (LCM) and structures, especially for bi-material structures. The intended analysis has application in engineering design and monitoring of knowledge based systems made of LCM (for instance thin coating on turbines and wind propellers), satisfying the increasing demand for high strength, high toughness, and questions connected with critical length of interface delamination, energetic conditions for change of a direction of a crack, critical mechanical loading for a full degradation of a structure, corrosion-resistance and wear-resistance properties and finally for lower failure rates during manufacturing and service processes. The main aim of the project is to develop and validate an analytical model proposed by the applicants Ivanova, Becker et al, (2010) for solving the dynamic interface cohesive behaviour and the delamination in a bi-material structure. The elastic-brittle interface behaviour has been already considered. In order to complete the problem, these investigations have to be continued and directed to cohesive interface behaviour and respective delamination. The application of the results obtained to turbines and wind propellers is one of the goals of the proposal. The analytical solution method is based on the modified dynamic Shear Lag method chosen to find the debond length along the interface and to predict the load-carrying capacity of a bi-material structure as a part of wind propellers. The Shear Lag method is very effective because of its simplicity (1D model). Its successful application in the static case has been proven by Ivanova et al (2009). Simulation studies will be proceeded in order to evaluate such important effects as: geometry of the bi-material structures, elastic and cohesive behaviour of the interface, frequency and amplitude influence of the external loading on debond length, as well as safety zones for the structure.