Seminar

 The objective of this study is to develop a Finite Element (FE) model using the commercial FE package - ABAQUS for simulating the viscoelastic deformation of a self-gravitating compressible earth induced by surface loading. 

  The first part of this study aims at using the Normal Mode (NM) method to calculate the load induced responses for benchmarking with the FE model. Because no analytical solution has been found for multi-layer compressible models, results can only be calculated by the numerical integration method (NIM), which is less reliable due to numerical errors. The size of numerical errors associated with the NIM are quantified and the effect of the unstable RT-modes is studied. Analysis is carried out to choose the most suitable earth model among all the tested, for computing the load induced responses for benchmarking. 

  The second part of this thesis is about the development of FE model in ABAQUS. It is found that when the iterative stress transformation scheme (Wu 2004) is applied on compressible earth models, the output strain and displacements will also be transformed, which is undesirable for realistic applications. An alternative approach is proposed to achieve the objective of this study. Benchmark tests are carried out on incompressible and compressible earth models. Good agreement is obtained between the results calculated by the proposed approach and those obtained by the conventional NM method.