Coupling between Strain Induced Damage, the Degradation of Thermal Properties and Stress-Strain Response of Ceramic Matrix Composites

申请拨款聘请一名研究助理和一名研究生，研究编织陶瓷基复合材料的制造孔隙/损伤、应变引起的损伤、热性能退化和应力-应变响应之间的耦合模型。该项目是对GR/K81256和后续项目研究的延续。第一种是简单的平纹0/90编织DRL-XT C/SiC CMC，其先前已被广泛研究。将使用经典的有限元单元建模技术对材料进行研究，以建立制造孔隙率和应变引起的损伤与热导率退化的耦合建模方法。建模将在纤维/丝束/基质材料的水平上进行，驱动程序是根据复合材料的组成相（即纤维、纤维丝束、不同材料之间的界面和将复合材料结合在一起的基体。研究的下一部分将是在DRL-XT C/SiC与计算上更经济和概念上更简单的二元建模技术;为了建立其可行性和准确性。建立了这一点，二元建模技术用于第一种材料，将用于研究第二种材料。这是一种更复杂的HITCO C/C 8-Satin组织，广泛用于工业工程部件。将研究8-Satin CMC的制造孔隙率、应变引起的损伤和热性能退化之间的耦合。对于这两种材料，计算机建模的成功将根据在GR/K81256资助下收集的实验应力-应变-热导率数据来判断。该研究将建立用于表征制造孔隙率的方法，用于使用半逆技术和散装复合材料实验数据来引出纤维、丝束、界面和基质的物理和机械性能。最后，二元模型技术将被用来预测一个简单的工程部件在热载荷和机械载荷的联合作用下的应力-应变-损伤-热输运响应，并评估这种方法的可行性。将提出建议的可行性和可能的限制，用于热机械建模，如复杂的编织复合材料。

Funds are sought to employ a Research Assistant and a Research Student to research the modelling of the coupling between manufacturing porosity/damage, strain-induced damage, the degradation of thermal properties and stress-strain response of woven Ceramic Matrix Composites (CMCs). The project is a continuation of research done on GR/K81256, and on subsequent projects.Two CMC materials have been selected. The first is a simple plain 0/90 weave DRL-XT C/SiC CMC which has previously been studied extensively. The material will be researched using classical Finite Element unit cell modelling techniques to establish methods for modelling the coupling of manufacturing porosity and strain-induced damage with the degradation of thermal conductivity. The modelling will take place at the level of the fibre/tow/matrices materials, with the driver being to predict bulk composite properties from the physical and mechanicl properties of the constituent phases of the composite i.e. fibres, tows of fibres, interfaces between different materials and the matrices which hold the composite together.The next part of the research will be to repeat this modelling exercise on the DRL-XT C/SiC with the more computationally economic and conceptually simple Binary Modelling technique; with a view to establishing its viability and accuracy.Having established this, the Binary Modelling technique used on the first material, will be used to study the second one. That is a more complex HITCO C/C 8-Satin weave which is extensively used in industrial engineering components. The coupling between manufacturing porosity, strain-induced damage and the degradation of the thermal properties of the 8-Satin CMC will be researched. For both materials, success of the computer modelling will be judged against experimental stress-strain-thermal conductivity data collected under grant GR/K81256.The research will establish mehodologies for characterisation of manufacturing porosity, for eliciting physical and mechanical properties of fibres, tows, interfaces and matrices, using semi-inverse techniques and bulk composite experimental data.Lastly, the Binary Modelling technique will be used to predict the stress-strain-damage-thermal transport response of a simple engineering component subjected to combined thermal and mechanical loading; and to assess the viability of the approach. Recommendations will be made on viability and possible constraints to use for thermo-mechanical modelling e.g. complex woven composites.