Micromechanics FEM Predict Effective Elastic Modulus Of Micro-short Fiber Reinforced Composites

The mechanical properties of micro-short fiber reinforced resin matrix composites will be improved only with small volume fraction(3%-5%) reinforced materials because special property of micro-short fiber, and this kind of composite is studying and applying widely these years. In the present thesis, effective elastic modulus prediction of micro-short fiber reinforced composites has been studied.At first, some micromechanics foundation theories and methods for effective elastic modulus prediction are introduced. And then Mori-Tanaka Equivalent Inclusion Theory and which theory considered interface described.Inclusion must be ellipsoidal when the Classical Mori-Tanaka method is used, so this thesis put forward a new method which is Mori-Tanaka method combined with Finite Element Method, and the new method is suitable for arbitrary shape inclusion. The calculation method and FEM model was expressed in order to calculate effective elastic modulus of composites by Mori-Tanaka FEM method.Using Mori-Tanaka FEM method and 2-D finite element model, the following contents were been systematically investigated:(1) At the assumption of good interfacial bonding of composite, without considering plastic deformation and residual thermal stress, the influence law of composites stress/strain and effective elastic modulus with micro-short fiber properties has been investigated, which properties include aspect ratio, volume fraction, single orientation and random orientation of micro-short fibers.(2) Building the interface model and considering elastic modulus of interface as variable, the influence law of composites mechanical property with interface elastic property has been studied.The result of the research may be applied to optimize the structure of composites and improve the composites directional property.