{"id":1986,"date":"2014-01-19T21:10:00","date_gmt":"2014-01-19T21:10:00","guid":{"rendered":"http:\/\/www.amzsaki.com\/?page_id=1986"},"modified":"2020-09-01T02:53:42","modified_gmt":"2020-09-01T02:53:42","slug":"simfem-a-finite-element-package-for-geomechanics","status":"publish","type":"page","link":"https:\/\/www.amzsaki.com\/?page_id=1986","title":{"rendered":"sim|FEM, a finite element package for geomechanics analysis"},"content":{"rendered":"
\"transitionalmesh\"<\/a>
Use of transitional elements reduces computation time while preserving solution accuracy where it matters the most.<\/figcaption><\/figure>\n

The development of sim|FEM grew out of the need to analyze problems in geomechanics as part of my research at Concordia University. The program is mainly written by me with the aid of some of my students as part of their research projects. The program is based on finite element theories specifically to analyze displacements and stresses occurring in geologic media. The goal of the program is the computation of displacements and stresses occurring in soils or rocks when subjected to self-weight (gravity) or some form of disturbance, such as the process of excavation, mining or tunnelling. In addition to stress analysis, sim|FEM can compute flow through porous medium as modelled using Laplace’s equation to represent groundwater flow. Both 2D and 3D elements are implemented in sim|FEM for stress analysis, while thus far only 2D elements exist for groundwater flow.<\/p>\n

sim|FEM was conceived to fill the gap existing in commercial software offerings with regard to the ease of expandability and adding new features, while having a full control over the source code. Some of my work is related to the development and use of so called transitional elements. These elements connect meshes with first order (e.g. 4-noded quadrilaterals) to second order (e.g. 8-noded quadrilaterals) using elements that on one of their sides (or faces) have first order interpolation (2 nodes per edge) and on the adjacent side (or face in 3D), second order interpolation (3 nodes per edge). To learn more about the topic, see some of my papers<\/a>.<\/p>\n

Since one of my interests is software optimization for performance, sim|FEM serves as a testbed for the development of efficient solvers arising in the solution of finite element problems. The use of both algorithmic acceleration and software libraries such as Apple’s Accelerate framework, Nvidia’s CUDA or OpenCL results is considerable speedups achieved. Some effort has been made to develop parallel solvers using OpenMP and MPI within sim|FEM, but those are not ‘officially’ avaliable.<\/p>\n

The development environment for sim|FEM is C++ using Apple’s Xcode environment. Since only pure C++ is used, sim|FEM can be compiled on almost everything, even a coffee grinder, if it supports a C++ compiler. Seriously, it was successfully compiled, in addition to a Mac, under Windows’ Visual Studio, SGI’s MIPSpro compilers and gcc in Linux.<\/p>\n

The following short sections illustrate the current, and ever evolving, capabilities of sim|FEM.<\/p>\n

\"Principal<\/a>
Principal stresses around two circular excavations.<\/figcaption><\/figure>\n

<\/h2>\n

Element library<\/h2>\n

For groundwater flow analysis the following elements are currently implemented in 2D:<\/p>\n