The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Lu Xi-wang - One of the best experts on this subject based on the ideXlab platform.
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Modeling of braiding parameter impact on pore size and porosity in a tubular braiding fabric
E-polymers, 2017Co-Authors: Chaojing Li, Zou Ting, Fan Zhao, Fujun Wang, Xiaoming Wang, Lu Xi-wangAbstract:AbstractTubular braiding fabric is widely used in developing tissue-engineered scaffolds, and is especially suitable for connective tissues like ligaments and tendons. The pore size and porosity of braiding structure scaffolds not only highly affect cell adhesion and proliferation, but also influence the mechanical behavior of those scaffolds. It is important to develop braiding scaffolds with controllable pore size and distribution. The purpose of this work is to add insight to the mechanics of this passive pore structure control system. Thus, some constitutive equations were established to reveal the relationship between braiding technical parameters (including the number of spindles, braiding structure, cylindrical Mandrel Radius, and yarn diameter) and the pore size, the porosity of tubular braiding fabric by the mathematical modeling method. Through this model, pore size and the porosity of the tubular braiding scaffold can be precisely controlled by quantitatively adjusting braiding technical parameters. Furthermore, the reliability and accuracy of this model were verified by the experimental data.
M M Mahdavi - One of the best experts on this subject based on the ideXlab platform.
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upper bound analysis of tube extrusion process through rotating conical dies with large Mandrel Radius
Journal of Solid Mechanics, 2015Co-Authors: H Haghighat, M M MahdaviAbstract:In this paper, an upper bound approach is used to analyze the tube extrusion process through rotating conical dies with large Mandrel Radius. The material under deformation in the die and inside the container is divided to four deformation zones. A velocity field for each deformation zone is developed to evaluate the internal powers and the powers dissipated on all frictional and velocity discontinuity surfaces. By minimization of the total power with respect to the slippage parameter between tube and the die and equating it with the required external power, the extrusion pressure is determined. The corresponding results for rotating conical dies are also determined by using the finite element code, ABAQUS. The analytical results show a good coincidence with the results by the finite element method with a slight overestimation. Finally, the effects of various process parameters such as Mandrel Radius, friction factor, etc., upon the relative extrusion pressure are studied. © 2015 IAU, Arak Branch.All rights reserved.
Remko Akkerman - One of the best experts on this subject based on the ideXlab platform.
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Circular Braiding Process Simulation for a Pressure Vessel
Volume 6A: Materials and Fabrication, 2014Co-Authors: Johan H. Van Ravenhorst, Remko AkkermanAbstract:Pressure vessel manufacturing is currently dominated by the filament winding process. When higher production rates are required, circular braiding can be considered as an alternative because hundreds of yarns are deposited simultaneously from interlacing spools. The process has a high repeatability and is suited for automated series production, as is currently shown with the production of a-pillars and rockers in the automotive industry. Important manufacturing constraints related to the overbraiding of cylindrical pressure vessels are to avoid excessive jamming of the braid, typically occurring at a small Mandrel Radius, and to achieve a 100% cover factor at the largest Mandrel diameter. In this paper, design guidelines for braiding of cylindrical pressure vessels are proposed. It is shown that a proper choice of the yarn cross-sectional area size and of yarn width-to-thickness aspect ratio can improve the design feasibility, but an adjustment of the braid angle can be required as well.Copyright © 2014 by ASME
Mehdi Shekarzadeh - One of the best experts on this subject based on the ideXlab platform.
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effect of ratio Mandrel Radius to sheet thickness on the spring back in bending steel and aluminum sheets
2013Co-Authors: Mehdi ShekarzadehAbstract:Forming and forging processes are among the oldest and most important of materials-related technologies. Today, industry must continuously evaluate the costs of competitive materials and the operations necessary for converting each material into finished products. Manufacturing economy with no sacrifice in quality is paramount. Therefore, "precision" forming methods, net and near-net shape processing, and modern statistical and computer-based process design and control techniques are more important than ever. Bending is one of the important methods for manufacturing sheet metal components that is extensively applied in automotive industry and electronic devices. Spring-Back is an unavoidable phenomenon in sheet metal forming that occurs in the end of stamping process because of releasing elastic stress that results changing the final dimensions of sheet. So, Prediction of spring-back is essential for dimensional control of parts in the end of stamping process. In this project a finite element model is presented for simulation of U-bending process and also calculating the amount of spring-back. Comparison between finite element , numeral and experimental results is done for validating the finite element method.
Chaojing Li - One of the best experts on this subject based on the ideXlab platform.
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Modeling of braiding parameter impact on pore size and porosity in a tubular braiding fabric
E-polymers, 2017Co-Authors: Chaojing Li, Zou Ting, Fan Zhao, Fujun Wang, Xiaoming Wang, Lu Xi-wangAbstract:AbstractTubular braiding fabric is widely used in developing tissue-engineered scaffolds, and is especially suitable for connective tissues like ligaments and tendons. The pore size and porosity of braiding structure scaffolds not only highly affect cell adhesion and proliferation, but also influence the mechanical behavior of those scaffolds. It is important to develop braiding scaffolds with controllable pore size and distribution. The purpose of this work is to add insight to the mechanics of this passive pore structure control system. Thus, some constitutive equations were established to reveal the relationship between braiding technical parameters (including the number of spindles, braiding structure, cylindrical Mandrel Radius, and yarn diameter) and the pore size, the porosity of tubular braiding fabric by the mathematical modeling method. Through this model, pore size and the porosity of the tubular braiding scaffold can be precisely controlled by quantitatively adjusting braiding technical parameters. Furthermore, the reliability and accuracy of this model were verified by the experimental data.