We first propose an adaptive immersed finite element method based on the a posteriori error estimate for solving elliptic equations with non-homogeneous boundary conditions in general Lipschitz domains. The underlying finite element mesh need not fit the boundary of the domain. Optimal a priori error estimate of the proposed immersed finite element method is proved. The immersed finite element ...

In this paper, the direct differentiation method DDM for finite-element FE response sensitivity analysis is extended to linear and nonlinear FE models with multi-point constraints MPCs . The analytical developments are provided for three different constraint handling methods, namely: 1 the transformation equation method; 2 the Lagrange multiplier method; and 3 the penalty function method. Two n...

the transport of dissolved contaminants in groundwater is usually described by the advectiondispersion equation with reaction. several numerical methods for solving the one-dimensional are availableincluding finite difference methods, finite volume methods, and finite element methods. stringent conditions,such as small peclet (pe) and courant (cr) numbers, must be satisfied to ensure the accura...

A finite element method (FEM) formulation for the prediction of unknown steady boundary conditions in heat conduction for multi-domain three-dimensional solid objects is presented. The FEM formulation is capable of determining temperatures and heat fluxes on the boundaries where such quantities are unknown, provided such quantities are sufficiently over-specified on other boundaries. An inverse...

in the current study, an effort is made to determine three dimensional bearing capacity of rectangular foundations using discrete element method. the soil mass is modeled as discrete blocks connected with winkler springs. different factors affect the geometry of failure surface. six independent angles are used to define the failure surface. by trial and error, the optimum shape of failure surfa...

Offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. Thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. A safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. While the cost...

welding is one of the most important assembling methods which are widely applied in different applications. in service conditions, some of the weld joints which meet defects must be repaired. the residual stresses impress the operation and efficiency of the repair weldment. in this study, the temperature and the residual stress fields were investigated by both the finite element simulation and ...

The worldwide progress to date in experimental and computational studies on composite frame structures having rectangular concrete-filled steel tube (RCFT) beam-columns and steel girders and braces has revealed their exceptional seismic resistance. In this paper, a computational study to develop reliability-based performance-based seismic design guidelines of RCFT members is presented. A three-...

We study the mixed formulation of the stochastic Hodge-Laplace problem defined on a n-dimensional domain D (n ≥ 1), with random forcing term. In particular, we focus on the magnetostatic problem and on the Darcy problem in the three dimensional case. We derive and analyze the moment equations, that is the deterministic equations solved by the m-th moment (m ≥ 1) of the unique stochastic solutio...