Ivan Němec

Parallel Computing Procedure for Dynamic Relaxation Method on GPU Using NVIDIA's CUDA

This paper introduces a procedure for parallel computing with the Dynamic Relaxation method (DR) on a Graphic Processing Unit (GPU).This method facilitates the consideration of a variety of nonlinearities in an easy and explicit manner.Because of the presence of inertial forces, a static problem leads to a transient dynamic problem where the Central Difference Method is usedas a method for direct integration of equations of motion which arise from the Finite Element model.The natural characteristic of this explicit method is that the scheme can be easily parallelized. The assembly of a global stiffness matrix is not required.Due to slow convergence with this method, the high performance which GPUs provide is strongly suitable for this kind of computation.NVIDIAs CUDA is used for general-purpose computing on graphics processing units (GPGPU) for NVIDIAs GPUs with CUDA capability.

A New Cable-Pulley Algorithm in RFEM

Abstract The cable-pulley system is widely used for its advantages. In this paper, application of a new algorithm for the calculation of cables on pulleys is presented. Unlike other algorithms, this algorithm enables to take the magnitude of the radius of each pulley into account. This new algorithm is implemented in the RFEM program because of its higher accuracy and efficiency. Comparison of the commonly used algorithm, which ignores pulley radius, and the new algorithm is presented.

Parallel Computation on Multicore Processors Using Explicit Form of the Finite Element Method and C++ Standard Libraries

Abstract In this paper, the form of modifications of the existing sequential code written in C or C++ programming language for the calculation of various kind of structures using the explicit form of the Finite Element Method (Dynamic Relaxation Method, Explicit Dynamics) in the NEXX system is introduced. The NEXX system is the core of engineering software NEXIS, Scia Engineer, RFEM and RENEX. It has the possibilities of multithreaded running, which can now be supported at the level of native C++ programming language using standard libraries. Thanks to the high degree of abstraction that a contemporary C++ programming language provides, a respective library created in this way can be very generalized for other purposes of usage of parallelism in computational mechanics.

Form-Finding of Membrane Structures and Necessary Stabilization of this Process

The aim of this contribution is a form-finding process. It is the problem of initial pre-stressed shape generation of membrane constructions. The contribution deals with specific aspects of this process and the necessity of introducing stabilization with regard to its practical application. Individual examples will show the results of methods described in this paper.

DESIGN OF INITIAL SHAPE OF MEMBRANE STRUCTURES

Abstract The subject of this article is the question of design and analysis of membrane structures. The first part of this article deals with the problem of form-finding. It is the problem of searching for the initial shape of membrane structure. In the second part of the article, an example of design and analysis of the membrane structure of a stadium roof is presented. This work was carried out with respect to the intention of companies Dlubal Software, s.r.o. and FEM consulting, s.r.o. to create the module for finding initial shapes of membrane structures, which would consequently be implemented into the software RFEM.

PARAMETRIC STUDY OF THE STRUCTURAL RESPONSE OF NPP CONTAINMENT TO IMPACT LOADING

Abstract The presented article is a contribution to the discussion concerning nuclear safety which has intensified after the Fukushima Daiichi nuclear disaster. A parametric study concerning various materials, containment wall thicknesses and different aircraft speeds at the time of impact was performed. The aim of this study was to establish damage extent of various variants of a containment structure. Containment damage was evaluated by means of the value of maximum permanent deformation and plastic strain extent. The purpose of this study was also to foster experiential suggestions for improving the explicit method in the RFEM program in order to release it for RFEM users.