scholarly journals Analysis of the multilayer woven fabric behaviour during the forming process: focus on the loss of cohesion within the woven fibre network

2019 ◽  
Vol 20 (4) ◽  
pp. 407
Author(s):  
Ahmad Rashed Labanieh ◽  
Christian Garnier ◽  
Pierre Ouagne ◽  
Olivier Dalverny ◽  
Damien Soulat
Keyword(s):  
Woven Fabric ◽  
Carbon Fabric ◽  
Mechanism Of Formation ◽  
Forming Force ◽  
Forming Process ◽  
Plane Shear ◽  
Blank Holder ◽  
Fibre Network ◽  
Process Loss

The first step in the composite manufacturing process consists of forming a flat textile reinforcing structure into a 3D shape. The quality of the final composite part is affected by the presence of defects induced during the forming process. Loss of cohesion in the woven fibre network (intra-ply yarn sliding) is a frequent defect in the forming process. It is expected when the cohesion between the yarns is weak or when the blank holder pressure is high. However, the mechanism of formation of this defect is not fully understood. In the present study, forming experiments with friction-based holder have been conducted for a monolayer twill woven carbon fabric in two orientations and for two plies of this fabric with different relative orientations. The occurrence of the intra-ply yarns sliding has been observed as a function of the blank holder pressure. A correlation between the occurrence of this defect and the fabric orientation has been noticed. Furthermore, the effect of the fabric orientation, number of plies, relative plies orientation and blank holder pressure on the recorded forming force and on the fabric in-plane shear is also reported and analysed.

scholarly journals Analysis of the Blank Holder Force Effect on the Preforming Process Using a Simple Discrete Approach

2013 ◽  
Vol 554-557 ◽  
pp. 441-446 ◽  
Author(s):  
Walid Najjar ◽  
Xavier Legrand ◽  
Philippe Dal Santo ◽  
Damien Soulat ◽  
Serge Boude
Keyword(s):  
Process Parameters ◽  
Material Behavior ◽  
Woven Fabric ◽  
Physical Parameters ◽  
Angle Distribution ◽  
Forming Process ◽  
Plane Shear ◽  
Blank Holder ◽  
Moulding Process ◽  
Discrete Approach

Simulation of the dry reinforcement preforming, first step of the Resin Transfer Moulding process, become necessary to determine the feasibility of the forming process, compute the fiber directions in the final composite component, and optimize process parameters during this step. Contrary to geometrical approaches, based on fishnet algorithms, finite element methods can take into account the actual physical parameters, the real boundary conditions and the mechanical behavior of the textile reinforcement. The fabric can be modeled either as continuum media with specific material behavior [5, 6], or using discrete structural elements to describe the textile structure at the mesoscopic scale. A semi-discrete approach, which is a compromise between the above continuous and discrete approaches, is also used for simulation. A discrete approach for the simulation of the preforming of dry woven reinforcement has been proposed and presented in a previous paper. This modelling is based on a “unit cell” formulated with elastic isotropic shells coupled to axial connectors. The connectors, which replace bars or beams largely studied in other discrete approaches, reinforce the structure in the yarn directions and naturally capture the specific anisotropic behavior of fabric. Shell elements are used to take into account the in-plane shear stiffness and to manage contact phenomena with the punch and die. The linear characteristic of the connectors, has been extended to a non linear behaviour in the present paper to better account for fabric undulation. Using this numerical model, we propose, in this work to study the effect of process parameters on the woven fabric deformation during the performing step. The emphasis will be placed on the analysis of the influence of the blank holder pressure on the shear angle distribution.

Schwingungsüberlagertes Axialformen/Superimposed Oscillated Axial Forming

2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Surface Quality ◽  
Economic Importance ◽  
Combined Effect ◽  
Wird Eine ◽  
Forming Force ◽  
Forming Process ◽  
Forming Technology ◽  
Great Economic Importance ◽  
Gear Geometry

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.

Influence of Roller on Tooth Height of Internal Spline Formed by Spin-Forming

2012 ◽  
Vol 522 ◽  
pp. 268-271
Author(s):  
Ling Yan Sun ◽  
Qin Xiang Xia ◽  
Xiu Quan Cheng ◽  
Bang Yan Ye
Keyword(s):  
New Technology ◽  
Internal Surface ◽  
Height Distribution ◽  
Forming Force ◽  
Nose Radius ◽  
Forming Process ◽  
Element Simulation ◽  
Gear Manufacturing ◽  
Spinning Force

Spin-forming of part with internal tooth is a new technology of the near-net forming in gear manufacturing field. And the main purpose of the parts spin-forming is to shape teeth on the internal surface of blank. In order to improve the forming quality of internal tooth, the effect of roller on tooth height of spline was investigated by processing experiments and finite element simulation. The result indicates that, for full-radius roller, a large nose radius has also witnessed a discernible growth in spinning force and tooth height; considering the uniformity of tooth height distribution of spun part and decrease in forming force, the bio-conical roller is more suitable for this forming process

scholarly journals Analysis of the Mechanical and Preforming Behaviors of Carbon-Kevlar Hybrid Woven Reinforcement

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4088
Author(s):  
Zhengtao Qu ◽  
Sasa Gao ◽  
Yunjie Zhang ◽  
Junhong Jia
Keyword(s):  
Fiber Type ◽  
Engineering Application ◽  
Single Layer ◽  
Plane Shear ◽  
Blank Holder ◽  
Out Of Plane ◽  
Woven Reinforcement ◽  
Hybrid Reinforcement ◽  
Shear Behaviors

Carbon-Kevlar hybrid reinforcement is increasingly used in the domains that have both strength and anti-impact requirements. However, the research on the preforming behaviors of hybrid reinforcement is very limited. This paper aims to investigate the mechanical and preforming behaviors of carbon-Kevlar hybrid reinforcement. The results show that carbon-Kevlar hybrid woven reinforcement presents a unique “double-peak” tensile behavior, which is significantly different from that of single fiber type reinforcement, and the in-plane shear deformation demonstrates its large in-plane shear deformability. Both the tensile and in-plane shear behaviors present insensitivity to loading rate. In the preforming process, yarn slippage and out-of-plane yarn buckling are the two primary types of defects. Locations of these defects are closely related to the punch shape and the initial yarn direction. These defects cannot be alleviated or removed by just increasing the blank holder pressure. In the multi-layer preforming, the compaction between the plies and the friction between yarns simultaneously affect the quality of final preforms. The defect location of multi-layer preforms is the same as that of single-layer, while its defect range is much wider. The results found in this paper could provide useful guidance for the engineering application and preforming modeling of hybrid woven reinforcement.

Research on Stamping of Aluminum Alloy Hemispherical Components Based on Numerical Simulation and Experiments

2010 ◽  
Vol 97-101 ◽  
pp. 236-239
Author(s):  
Cheng Jun Han ◽  
Xin Bo Lin ◽  
Yan Bo Li
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Product Quality ◽  
Experimental Research ◽  
Simulation Software ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Wrought Aluminum

Experimental research on stamping of wrought aluminum alloy has been an important issue at home and abroad. In this paper, taking stamping of aluminum alloy hemispherical components for example, the effects of blank holder force (BHF) on stamping forming process of aluminum alloy are explored by methods of experiments and numerical simulation. Through experiments, the forming laws of hemispherical components are found out. The research shows that the BHF has significant effects on the quality of stamping components and reasonable BHF can greatly improve the formability of hemispherical components. Additionally, by applying simulation software in stamping, the development circle of product and its moulds can be shortened, and product quality and its competitiveness in the market can be improved.

Numerical simulation of the effects of the space-variant blank-holder force and geometrical variables in the deep-drawing process

2005 ◽  
Vol 40 (4) ◽  
pp. 375-384
Author(s):  
L Wang ◽  
T. C Lee
Keyword(s):  
Complex Shape ◽  
Geometrical Parameters ◽  
Blank Holder Force ◽  
Minor Strain ◽  
Forming Process ◽  
Blank Holder ◽  
Common Problems ◽  
Blank Size ◽  
Space Variant

The increase in quality requirements for the formed products makes it desirable to find an effective way of controlling the process to achieve complex shape products without defects. It has been proven by many researchers that the space-variant blank-holder force can improve the quality of forming to achieve a targeted shape product (no wrinkling, a high drawing depth, less variation in thickness, etc.). In the forming process, the most common problems, tearing and wrinkling, generally result from the strain condition. In this paper the effect on the strain path with various types of space-variant blank-holder force and other geometrical parameters, such as the fillet radius, the blank size, and the clearance between the die and the punch, were compared and analysed. The results showed that the space-variant blank-holder force and some geometrical parameters affect the strain distribution to various extents during the forming process. The parameters influence the negative minor strain much more than the maximum major strain.

Finite Element Analysis on Flanging Forming of Car Spoke Parts

2012 ◽  
Vol 602-604 ◽  
pp. 1955-1958
Author(s):  
Xiao Gang Qiu
Keyword(s):  
Great Influence ◽  
Production Quality ◽  
Computation Method ◽  
Round Hole ◽  
Forming Process ◽  
Element Analysis ◽  
Blank Holder ◽  
Material Parameters ◽  
Hole Flanging

To improve the production quality of mini-car spoke components, the forming process of mini-car spoke components is numerically simulated by DYNAFORM, and the geometry models of punch, die, blank holder and sheet metal are established, the effect of round-hole flange coefficient, material parameters and forming craft on flanging forming is evaluated by simulation computation method, and the suggestions for improvement are discussed. The results indicates that the increase in material yield strength has a great influence on flanging cracking; and through improving flanging process, the cracking defects of round-hole flanging in the spoke components can be controlled, the cracking rate reduces to 0.1 ‰, and the better product quality can be obtained.

Numerical Simulation of Cylinder Part Based on Dynaform

2012 ◽  
Vol 184-185 ◽  
pp. 337-340
Author(s):  
Ze Hao Hu ◽  
Juan Liu ◽  
Nan Wang
Keyword(s):  
Numerical Simulation ◽  
Experimental Method ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder

The forming process of a typical cylinder part is simulated by the platform of Dynaform. The influence of blank holder force (BHF), punching speed and clearance between punch and die on the quality of forming part is assessed by the orthogonal experimental method. The value of BHF of 20KN, punching speed of 2000mm/s and clearance between punch and die of 1.1mm which are the optimized parameters value are obtained.

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

scholarly journals The Effect of Process Parameters in Helical Rolling of Balls on the Quality of Products and the Forming Process

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2125 ◽  
Author(s):  
Janusz Tomczak ◽  
Zbigniew Pater ◽  
Tomasz Bulzak
Keyword(s):  
Metal Flow ◽  
Experimental Tests ◽  
Rolling Process ◽  
Helical Rolling ◽  
Forming Process ◽  
University Of Technology ◽  
Quality Of Products ◽  
Skew Rolling

This paper presents selected numerical and experimental results of a skew rolling process for producing balls using helical tools. The study investigates the effect of the billet’s initial temperature on the quality of produced balls and the rolling process itself. In addition, the effect of billet diameter on the quality of produced balls is investigated. Experimental tests were performed using a helical rolling mill available at the Lublin University of Technology. The experiments consisted of rolling 40 mm diameter balls with the use of two helical tools. To determine optimal rolling parameters ensuring the highest quality of produced balls, numerical modelling was performed using the finite element method in the Forge software. The numerical analysis involved the determination of metal flow kinematics, temperature and damage criterion distributions, as well as the measurement of variations in the force parameters. The results demonstrate that the highest quality balls are produced from billet preheated to approximately 1000 °C.

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