Prediction of Distortion Produced in Welded Structures During Straightening Process Using the Inherent Strain Method

In order to optimize the straightening process, it is necessary to predict the deformation due to local heating. Numerical simulation is an advantageous way to do this. In this study, Osaka University’s inherent strain based welding simulation code JWRIAN is modified so that inherent strain’s equivalent nodal forces are calculated in cases where the inherent strain confines within narrow region whose size is smaller than element size. In the developed code, the initial strain force vector and element stiffness matrix’s non-linear term which includes stress components are integrated using higher order (e.g. 20 × 20 × 6 for 4-nodes shell elements) Gauss-Legendre quadrature while other quantities are evaluated by using ordinary order (2 × 2 × 2) quadrature. The validity of the developed software is examined by comparing rectangular plate’s angular distortion due to gas line heating calculated by three-dimensional thermal-elastic-plastic analysis and that calculated by the developed system.

Study on the Treatment of Nonlinear Roll Damping in Hydrodynamic Calculation and Structural Analysis

In order to insure the consistent wave loads in hydrodynamic calculation and structural analysis, the treatment of nonlinear roll damping in roll motion, wave torsional moment and structural analysis are studied. The nonlinear roll damping moment is applied to the structural model by means of the equivalent nodal forces. Taking a supply ship and a FPSO as example, the calculation results show that the problem of torsional moment distribution divergent on the bow and the unbalanced structural model is improved greatly, which would be helpful to provide the reliable basis to design the structures.

MICRO-FINITE ELEMENT MODELING OF WRINKLE FORMATION FOR CELL LOCOMOTION APPLICATIONS

We developed a generic numerical procedure using the finite element method (FEM) for modeling wrinkles on an elastic thin membrane. The geometric characterization of wrinkles formed in an elastic membrane, which is caused by a crawling cell, may help in understanding the forces acting between a cell and its compliant substrate. In this study, the equivalent nodal forces, obtained from the virtual changes in the element internal energy, were differentiated to calculate the stiffness matrix. Micro-wrinkles can be computed as a function of membrane thickness which affects the stiffness matrix. This model may be used for applications in cell mechanobiology.

Geometric Nonlinearity Analysis of Composite Laminated Box Beam

In this paper, the differential equations of composite laminated box beams are established based on the principle of minimum potential energy and the variational method. Considering shear lag and shear deformation effects, elastic stiff matrix, geometric nonlinearity stiff matrix and equivalent nodal forces vector of composite laminated box beam element are given. And a finite element program is developed, then a new computing analysis theory for composite laminated box beam is given, both considering shear lag, shear deformation and geometric nonlinearity effects.

Development of Orthotropic Beam Element Using a Consistent Higher Order Deformation Theory

In order to analyze beam structures more accurately and effectively, a two-node orthotropic beam element is proposed. This beam element is formulated using a consistent higher order deformation theory of orthotropic beams of which the transverse normal deformation can be effectively estimated. The stiffness matrix and the vector of equivalent nodal forces of the beam element are derived explicitly by the Galerkin method. In order to examine the reliability and the characteristics of the beam element, the analytical and the finite element solutions of a simple cantilevered beam are compared with each other. As a result, the following conclusions are obtained; (1) the accuracy of the suggested orthotropic beam element is very excellent and so the transverse normal deformation and shear stress of an orthotropic beam can be effectively estimated. (2) It can be used for accurately analyzing the general beam structures regardless of the Euler's or the Timoshenko's beam.

A Nodal Load Model of 3-D Finite Element Analysis for a Crankshaft of a Truck-Mounted Compressor

In order to analyze the stresses and deformations of a crankshaft of a truck-mounted compressor by means of finite element method, the most important and difficult thing is how to determine the external force model on a crankshaft. The objective of this paper is to present a new load model of 3-D finite element analysis for a crankshaft of a truck-mounted compressor used in an oil field, i.e., the contacting-distribution forces are transferred into equivalent nodal forces. Firstly, the contacting-distribution forces between the crankshaft and the links are analyzed; secondly, formulations of equivalent node forces for the working conditions of 0° and 75° are deduced; finally, the crankshaft of a gas-engine driven truck-mounted compressor is taken as an illustration.