Search results for: fem analysis
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Application of mesh deformation for modeling of conformal RF components with 3D FEM
PublicationIn this paper, a method of analysis of conformal RF components has been proposed. In this approach, modeling of a curved structure is based on mesh deformation of planar objects rather than the construction of conformal geometry at CSG level. Since the model is represented as a 3D mesh, the deformation only requires the calculation of nodes position in the bent structure. The results of the proposed algorithm have been validated...
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Nondestructive methods complemented by FEM calculations in diagnostics of cracks in bridge approach pavement
PublicationNondestructive methods of road pavement diagnostics are an alternative to traditional approach to pavement failure investigation. The article presents a detailed multidisciplinary inspection carried out using ground-penetrating radar (GPR), laser scanning technology and finite element method (FEM) calculations. It was done in order to assess the factors that contributed to occurrence of premature cracks of a bridge approach pavement....
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Numerical tests of time-stepping schemes in the context of FEM for 6-field shell dynamics
PublicationThe paper deals with integration of dynamic equations of irregular shells performed with relatively long time steps. Numerical instability appearing often in this kind of analysis motivated the authors to present some studies based on numerical tests referring to convergence problems of finite element analysis as well the applied stability conditions. The analysis is carried out on simulations of shell dynamics with the where the...
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Influence of nonlinearities on the efficiency and accuracy of FEM calculations on the example of a steel build-up thin-walled column
PublicationDue to the increase of computing capabilities of standard processing units, it is possible to perform complex analyses, considering a number of nonlinearities, such as geometric, material and boundary (contact) even on personal computers. In the paper, the authors have analysed the efficiency and accuracy of standard PC’s FEM calculations performed in Abaqus CAE 2017 software on the example of a critical load assessment of a thin-walled...
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Composite Sandwich Footbridge – Numerical ESL FEM Calculations vs. In Situ Measurements
PublicationSelected results of the static analysis of composite sandwich footbridge with the corresponding in situ measured values are compared in the paper. The analysed bridge is a research object, which was built in 2015 and is currently located at the Gdańsk University of Technology campus. Since it is a novel structure, a proper definition of the bridge numerical model, allowing its safe design, is very important. Therefore, instead...
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FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublicationThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
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Compressed Projection Bases for Model-Order Reduction of Multiport Microwave Components Using FEM
PublicationThis paper presents a projection basis compression technique for generating compact reduced-order models (ROM) in the FE analysis of microwave devices. In this approach redundancy is removed from the projection basis by means of the proper orthogonal decomposition technique applied to the projected system of linear equations. Compression allows for keeping the size of a reduced-order model as small as possible without compromising...
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Estimation of Failure Initiation in Laminated Composites by means of Nonlinear Six-Field Shell Theory and FEM
PublicationThe monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...
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Block Conjugate Gradient Method with Multilevel Preconditioning and GPU Acceleration for FEM Problems in Electromagnetics
PublicationIn this paper a GPU-accelerated block conjugate gradient solver with multilevel preconditioning is presented for solving large system of sparse equations with multiple right hand-sides (RHSs) which arise in the finite-element analysis of electromagnetic problems. We demonstrate that blocking reduces the time to solution significantly and allows for better utilization of the computing power of GPUs, especially when the system matrix...
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A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric Complex-Valued Matrices Obtained Using Higher-Order FEM
PublicationThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complex-valued matrices obtained using the higher-order finite-element method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the low-order...
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An MOR Algorithm Based on the Immittance Zero and Pole Eigenvectors for Fast FEM Simulations of Two-Port Microwave Structures
PublicationThe aim of this article is to present a novel model-order reduction (MOR) algorithm for fast finite-element frequency-domain simulations of microwave two-port structures. The projection basis used to construct the reduced-order model (ROM) comprises two sets: singular vectors and regular vectors. The first set is composed of the eigenvectors associated with the poles of the finite-element method (FEM) state-space system, while...
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Macromodeling techniques for accelerated finite element analysis
PublicationThis paper deals with the Model Order Reduction applied locally in the Finite Element Method (FEM) analysis. Due to the reduction process, blocks of FEM system matrices associated with selected subregions of the computational domain are projected onto the subspaces spanned by the vectors of suited orthogonal projection basis. In effect, large and sparse FEM matrices are replaced with small and dense ones, called macromodels. This...
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Geometrically nonlinear analysis of shells - Benchmark problems for Autocad Robot Analysis Professional
PublicationThe aim of this work is to verify the suitability of commercial engineering software for geometrically nonlinear analysis of shells. This paper deals with the static, geometrically nonlinear analysis of shells made of an isotropic material. The Finite Element Method (FEM) is chosen to solve the problem. The results of the commercial software Autocad Robot Structural Analysis Professional (ARSAP) are compared with the litera-ture...
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Damage Analysis of Tensioning Cable Anchorage Zone of a Bridge Superstructure, Using CDP Abaqus Material Model
PublicationNumerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented in this paper. It aims to identify why severe concrete cracking occurs during the tensioning process in the vicinity of anchor heads. In order to simulate the tensioning, among others, a so-called local numerical model of a section of the bridge superstructure was created in the Abaqus Finite Element Method (FEM) environment. The...
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The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
PublicationLike other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack...
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Macromodels for efficient FEM simulations of waveguides and resonators
PublicationThis paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublicationThe paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure...
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Numerical analysis and in situ tests of the Grot Rowecki Bridge in Warsaw
PublicationThe paper presents the FEM analysis of the reconstructed the Grot-Rowecki Bridge over Vistula river in Warsaw. The bridge has seven spans and consists of two independent structures with the longest spans of 120 m. After reconstruction the bridge is over 10 m wider. The numerical, nonlinear analysis has been con-ducted on a global and local FEM models. These models are defined so as they strictly comply with global structural bridge...
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Modal analysis of railway current collectors using Autodesk Inventor
PublicationThe paper presents the results of modal analysis of railway current collector type 160EC. In the first place, the analysis was carried out analytically for a simplified two lumped mass pantograph model. Then numerical analysis was conducted in the Autodesk Inventor (AI) on the prepared multibody model using the AI modal analysis algorithm, which is based on the finite element method (FEM). Model elements which are most relevant...
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Theoretical analysis of the cable-stayed bridge over brda river in Bydgoszcz
PublicationThe topic of this article is the numerical analysis carried out for the cable-stayed tram (road) bridge over Brda river in Bydgoszcz. The goal of numerical studies was the verification of project assumptions and construction solutions elaborated by the autonomous team. The bridge calculations were conducted on three independent FEM models The internal forces and the elements effort under different loading schemes were examined....