scholarly journals Draping modelization of stitched composite reinforcements

2021 ◽  
Author(s):  
Jin Huang ◽  
Nahiène Hamila ◽  
Philippe Boisse

In the aeronautic industry, thicker and more complex composite parts are required. Multi-layered reinforcements are widely used to achieve a certain thickness for the composite part. The tufting technology has become one of the most effective three-dimensional (3D) reinforcement technologies to improve the through-the-thickness mechanical properties of multi-layered reinforcements. A finite element model is proposed for the simulation of tufted reinforcements preforming. The textile reinforcement is modelled by shell elements, and the tufting thread is modelled by bar elements. A specific contact algorithm is developed to manage the interaction between reinforcements and tufting threads. This meso-macroscopic approach reduces the number of finite elements and saves calculation time compared to a mesoscopic model. The model shows a good prediction of deformations during the forming on a hemispherical shape.

2014 ◽  
Vol 980 ◽  
pp. 81-85 ◽  
Author(s):  
Kaoua Sid-Ali ◽  
Mesbah Amar ◽  
Salah Boutaleb ◽  
Krimo Azouaoui

This paper outlines a finite element procedure for predicting the mechanical behaviour under bending of sandwich panels consisting of aluminium skins and aluminium honeycomb core. To achieve a rapid and accurate stress analysis, the sandwich panels have been modelled using shell elements for the skins and the core. Sandwich panels were modelled by a three-dimensional finite element model implemented in Abaqus/Standard. By this model the influence of the components on the behaviour of the sandwich panel under bending load was evaluated. Numerical characterization of the sandwich structure, is confronted to both experimental and homogenization technique results.


Author(s):  
H Jamshidi Aval ◽  
S Serajzadeh ◽  
A H Kokabi

In this work, the effect of tool geometric parameters on thermo-mechanical behaviour in friction stir welding of AA5086 has been investigated. For doing so, the thermo-mechanical responses of material during welding with different tools have been predicted by a three-dimensional finite-element model using the finite-element code ABAQUS. In addition, welding experiments have been carried out to study the developed microstructures and the mechanical properties of welded alloy. The results show that tool geometry significantly affects the energy input, deformation pattern, plunge force, microstructures, and mechanical properties of the joint. The conical tool with the shoulder angle of 2° has been found to produce a larger deformation region as well as higher mechanical properties comparing with the cylindrical tools employed in this research. Additionally, tensile residual stresses are developed within the region around the weld centre-line, which gradually changes to compressive ones beyond the heat-affected zone. It is found that the ratio of heat generation from plastic to friction dissipation in the conical threaded pin is 44 per cent more than the cylindrical pin with similar shoulder diameter.


2014 ◽  
Vol 41 (10) ◽  
pp. 909-917 ◽  
Author(s):  
Michael Jolie ◽  
Ayman M. El Ansary ◽  
Ashraf A. El Damatty

Truncated conical vessels are commonly used as liquid containers in elevated tanks. Despite the widespread use of this type of structure worldwide, no direct code provisions are currently available covering its seismic analysis and design. The purpose of the current study is to assess the importance of considering the vertical component of ground accelerations when analyzing and designing this type of water-storage structure. The study is conducted using an equivalent mechanical model that estimates the normal forces that develop in the tank walls when subjected to vertical excitation. In addition, a three-dimensional finite element model has been developed by modeling the walls of the tank using shell elements. The finite element model has been employed to predict maximum membrane and overall meridional stresses due to both hydrodynamic and hydrostatic pressure distributions. Comparisons have been conducted to assess the significance of considering vertical excitation and to identify the magnification in meridional stresses due to bending effects associated with support conditions and large deformations.


2008 ◽  
Vol 33-37 ◽  
pp. 449-454 ◽  
Author(s):  
Wei Dong Song ◽  
Hai Yan Liu ◽  
Hui Lan Ren

The plate impact experiments have been conducted to investigate the dynamic behavior of 91W-6.3Ni-2.7Fe. Lagrangian analysis technique was introduced to discuss the mechanical properties of the tungsten alloys under high strain rate and the stress-strain curves of the tungsten alloys were given. Based on the experimental observations, the three-dimensional finite element models of projectile and tungsten alloy target are established by adopting ANSYS/LS-DYNA, Dozens of cases were performed to investigate the dynamic mechanical behavior of tungsten alloy target under impact loading. A good agreement between numerical predictions and experimental results was obtained, which suggests that the finite element model is efficient and credible to simulate the mechanical properties of tungsten alloys.


2019 ◽  
Vol 89 (19-20) ◽  
pp. 3916-3926
Author(s):  
Shanshan He ◽  
Longdi Cheng ◽  
Wenliang Xue ◽  
Zhong Lu ◽  
Liguo Chen

Regular cylinder metallic card clothing has a limited carding efficiency. As a result of the limited dimensions, any measurement between the cylinder and flat area is difficult to make. In this study, an approach is first proposed to simulate the flow field and a fiber finite-element model on the moving surface of the teeth and produce a new design of misaligned-teeth card clothing, with the aim of improving the carding efficiency. A comparison is made between regular and misaligned-teeth card clothing types with respect to flow field simulation and fiber mechanical properties. The results show that the force resulting from the tangential velocity between the cylinder and flat is as great as 1.86 × 10−3 N, sufficient to pull fiber out of tufts, and that the tangential velocity (from 3880 to 2500 mm/s) plays a major role in this area, as opposed to the axial velocity (from 0 to 190 mm/s). Through this comparison, the misalignment design can result in a different tangential velocity distribution from that of traditional card clothing, which helps fibers between two lines of teeth move into neighboring lines of teeth, thereby increasing the likelihood that fibers will be carded. For fiber mechanical analysis, different air forces are loaded on fibers. This comparison shows that for fibers in the channel, the misalignment can help fibers move toward the teeth. Therefore, this misaligned-teeth card clothing is thought to prove more effective in practice.


Author(s):  
Hong Shen ◽  
Jun Hu ◽  
Zhenqiang Yao

Efficient laser forming modeling for industrial application is still in the developing stage and many researchers are in the process of modifying it. Conventional three-dimensional finite element models are still expensive on computational time. In this paper, a finite element model adopting a shell-solid coupling technique is developed for the thermomechanical analysis of laser forming process. In the shell-solid coupling method, an additional shell element plane is utilized to transfer heat flux and displacement from the solid elements to the shell elements. The effects of the additional interface shell element thickness on temperature distribution and final distortion are investigated. The presented shell-solid coupling method is evaluated by the results of three-dimensional simulations and experimental data.


Author(s):  
S. Ramakrishna ◽  
S. K. Lim ◽  
S. H. Teoh

This paper presents effective extensional stiffness of plain-weft knitted fabric reinforced composites obtained from finite element analysis and analytical calculations. For micro-mechanical analyses, a unit cell, enclosing the characteristic periodic repeat pattern in the knitted fabric, is isolated and modeled. Psuedo three-dimensional finite element model is constructed using laminated shell elements. Composite extensional stiffness is estimated for plane-stress and plane-strain conditions. Further, stiffness and compliance averaging methods have been used to determine the upper and lower limits of composite stiffness. The models are explicitly based on the properties of fiber and matrix materials and orientation of yarns. Results obtained from the models are compared with experimental values.


2004 ◽  
Vol 31 (5) ◽  
pp. 782-796 ◽  
Author(s):  
Ying-Haur Lee ◽  
Hsin-Ta Wu ◽  
Shao-Tang Yen

The main objective of this study was to conduct in-depth parameter studies and verifications on three-dimensional (3-D) finite element (FEM) analysis of rigid pavements. A systematic analytical approach was utilized and implemented in a Visual Basic software package to study the effects of mesh fineness and element selection. The deflection and stress convergence characteristics of various 3-D shell and solid elements were investigated. Several guidelines in mesh fineness and element selection were developed and recommended. Using the principles of dimensional analysis, an additional dimensionless variable (h/a, where h is the thickness of the slab and a is the radius of the applied load) was identified and verified to have a substantial influence on ABAQUS runs using either 3-D shell elements or 3-D solid elements. Separate 3-D FEM stress and deflection databases were developed using all dimensionless variables. An example critical stress predictive model was developed. Together with the existing two-dimensional FEM research findings, a tentative stress prediction equation was proposed to illustrate its possible applications.Key words: rigid pavement, finite element model, stress, deflection, design, evaluation.


1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


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