scholarly journals Experimental and Numerical Determination of the Local Fiber Volume Content of Unidirectional Non-Crimp Fabrics with Forming Effects

2019 ◽  
Vol 3 (1) ◽  
pp. 19 ◽  
Author(s):  
Siegfried Galkin ◽  
Eckart Kunze ◽  
Luise Kärger ◽  
Robert Böhm ◽  
Maik Gude
Keyword(s):  
Volume Content ◽  
Fiber Orientation ◽  
Detailed Knowledge ◽  
Transverse Compression ◽  
Forming Process ◽  
Fiber Volume ◽  
Forming Simulation ◽  
Draping Simulation ◽  
Local Fiber

Detailed knowledge of the local fiber orientation and the local fiber volume content within composite parts provides an opportunity to predict the structural behavior more reliably. Utilizing forming simulation methods of dry or pre-impregnated fabrics allows for predicting the local fiber orientation. Additionally, during the forming process, so-called draping effects like waviness, gapping or shear-induced transverse compression change the local fiber volume content. To reproduce and investigate such draping effects, different manufacturing tools have been developed in this work. The tools are used to create fabric samples with pre-defined deformation states, representing the different draping effects. The samples are evaluated regarding the resulting fiber volume content. The experimental results are compared with the predictions of an analytical solution and of a numerical solution based on draping simulation results. Furthermore, the interaction of the draping effects at arbitrary strain states is discussed regarding the resulting fiber volume content.

Investigation on Tomographic-Based Nondestructive Characterization of Short Glass Fiber-Reinforced Composites as Obtained From Micro Injection Molding

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Jitendra Singh Rathore ◽  
Tomasz Konopczyński ◽  
Jürgen Hesser ◽  
Giovanni Lucchetta ◽  
Simone Carmignato
Keyword(s):  
Volume Content ◽  
Fiber Orientation ◽  
Fiber Composite ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Thin Wall ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Molded Part ◽  
Wall Injection

Abstract Quantitative assessment of fiber characteristics in composite parts is of great significance in order to correlate them with the fiber-induced mechanical properties. X-ray computed tomography (CT) is being successfully used as a three-dimensional nondestructive measuring technique for the analysis of fiber characteristics (mainly the fiber orientation and fiber volume content) in fiber-reinforced composite materials. However, the accuracy of such analyses depends on various factors (e.g., scanning parameters, resolution), which is the motivation for this study. The current work investigates the effect of CT scanning parameters and spatial resolution on the obtained fiber orientation and fiber volume content. First a simulation study is carried out using a computationally generated fiber composite model followed by a validation using a thin-wall injection-molded part. The findings showed that the effect of CT settings is not significant on the measurements, but the resolution affects the estimated fiber volume content adversely. A preliminary error calculation method is proposed for correcting the overestimation in the fiber volume content.

Verification of Numerical Roll Forming Loads with the Aid of Measurement Equipment

2014 ◽  
Vol 939 ◽  
pp. 373-380 ◽  
Author(s):  
Peter Groche ◽  
Christian Mueller ◽  
Lars Baeumer
Keyword(s):  
Numerical Model ◽  
Process Design ◽  
Mass Production ◽  
Roll Forming ◽  
Measurement Equipment ◽  
Forming Process ◽  
Forming Simulation ◽  
Roll Forming Process

Roll forming is an important forming process for profile manufacturing in mass production. The design of the process has an important influence on the quality of the products. Therefore, the knowledge of the occurring loads during the roll forming process, e.g. forces and pressures, is essential for the process design. However, the experimental determination of the occurring contact normal pressures in roll forming processes poses a challenge. Finite element simulations offer the potential to approximate contact normal loads and thus, enable a better process design. Nevertheless, due to simplifications of the numerical model, a realistic and reliable output of loads in roll forming is not possible. An enhanced numerical model could provide more valuable information. This paper will demonstrate the reproduction of realistic contact normal pressures and load forces in a roll forming simulation. To verify the numerical values, they will be compared to data gained by experiments.

Influence of Friction on the Loads in a Roll Forming Simulation with Compliant Rolls

2014 ◽  
Vol 611-612 ◽  
pp. 436-443 ◽  
Author(s):  
Christian Mueller ◽  
Xun Gu ◽  
Lars Baeumer ◽  
Peter Groche
Keyword(s):  
State Of The Art ◽  
Simulation Models ◽  
Roll Forming ◽  
Forming Process ◽  
Friction Behavior ◽  
Friction Coefficients ◽  
Forming Simulation ◽  
Compliance Behavior ◽  
Complex Measurement

Roll forming is an important economic forming process for manufacturing of profiles. For an optimal design of the process, it is important to determine the loads occurring during the forming process. Furthermore, the information of the load behavior enables an evaluation of the formability of the planned profiles with the chosen roll forming machine. An experimental determination of loads in roll forming processes requires a complex measurement setup in combination with a high amount of measurement devices. Hence, the analysis of roll loads by means of finite element simulation is of special interest. The use of roll forming simulations for the determination of geometrical outputs is state of the art. However, due to simplifications, a realistic and reliable output of roll loads in roll forming is impossible. Therefore, the compliance behavior under load and the frictional behavior have to be incorporated in the simulation model. The friction behavior in roll forming processes is presented to be very insignificant in literature. The value of the friction coefficients vary in a broad range. Due to lack of knowledge in the compliance behavior of the used stands, simulation models with rigid rolls are still state of the art. This paper will show the reproduction of realistic roll loads, e.g. torques and forces, in a roll forming simulation. Therefore, the friction coefficients of each roll-sheet metal contact will be gained experimentally and implemented in the numerical model. Furthermore, a characteristic compliance of the roll forming stands will be analyzed and also considered in the simulation. Finally, the influence of changing parameters, e.g. raise of the friction coefficients, on the roll loads will be investigated. To verify the simulation the numerical results will be compared to data gained by experiments.

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.

Topology Optimization of Blank Geometry for the Sheet Forming Process

2012 ◽  
Author(s):  
Saber DorMohammadi ◽  
Mohammad Rouhi ◽  
Masoud Rais-Rohani
Keyword(s):  
Topology Optimization ◽  
Volume Fraction ◽  
Structural Response ◽  
Sheet Forming ◽  
Forming Process ◽  
Exchange Method ◽  
Forming Simulation ◽  
Blank Shape Optimization ◽  
Blank Shape ◽  
Consistent Subset

The newly developed element exchange method (EEM) for topology optimization is applied to the problem of blank shape optimization for the sheet-forming process. EEM uses a series of stochastic operations guided by the structural response of the model to switch solid and void elements in a given domain to minimize the objective function while maintaining the specified volume fraction. In application of EEM to blank optimization, a sheet forming simulation model is developed using Abaqus/Explicit. With the goal of minimizing the variability in wall thickness of the formed component, a subset of solid (i.e., high density) elements with the highest increase in thickness is exchanged with a consistent subset of void (i.e., low density) elements having the highest decrease in thickness so that the volume fraction remains constant. The EEM operations coupled with finite element simulations are repeated until the optimum blank geometry (i.e., boundary and initial thickness) is found. The developed numerical framework is applied to blank optimization of a benchmark problem. The results show that EEM is successful in generating the optimum blank geometry efficiently and accurately.

Dynamic Load Effects of PVA Tail Sand Cement Base Composite Materials

2014 ◽  
Vol 518 ◽  
pp. 66-70 ◽  
Author(s):  
Wen Bo Bao ◽  
Shao Feng Zhang ◽  
Gao Hao Di ◽  
Wei Wei Ji ◽  
Li Hui Qu
Keyword(s):  
Composite Materials ◽  
Volume Content ◽  
Dynamic Load ◽  
Plate Thickness ◽  
Replacement Rate ◽  
Fiber Volume ◽  
Mechanics Performance ◽  
Load Effects ◽  
Base Composite ◽  
Pva Fiber

This paper studies that dynamic load affects mechanical properties of materials about composite tail ore different replacement rate, different PVA fiber volume content and different plate thickness. The phenomenon of the tests and results showed that:1) PVA tailings cement-based composite materials has low damage, strong integrity and strong energy dissipation under dynamic loading. 2) When the volume content is 2%, material resistance effect is best. 3) The study proves that 30 mm plate have good ductility and Size effect influence the material mechanics performance. 4) PVA tailings cement-based composite materials under dynamic loads ,as tailings content increases the performance indicators reduced. So the engineering applications recommended replacement rate of the tailings is 50%.

scholarly journals Influence of the Fiber Volume Content on the Durability-Related Properties of Polypropylene-Fiber-Reinforced Concrete

2020 ◽  
Vol 12 (2) ◽  
pp. 549
Author(s):  
Chenfei Wang ◽  
Zixiong Guo ◽  
Ditao Niu
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Volume Content ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Freeze Thaw ◽  
Chloride Environment ◽  
Polypropylene Fiber Reinforced Concrete

Polypropylene-fiber-reinforced concrete impacts the early shrinkage during the plastic stage of concrete, and the fiber volume content influences the durability-related properties of concrete. The purpose of this paper was to investigate the influence of fiber volume content on the mechanical properties, durability, and chloride ion penetration of polypropylene-fiber-reinforced concrete in a chloride environment. Tests were carried out on cubes and cylinders of polypropylene-fiber-reinforced concrete with polypropylene fiber contents ranging from 0% to 0.5%. Extensive data from flexural strength testing, dry–wet testing, deicer frost testing, and chloride penetration testing were recorded and analyzed. The test results show that the addition of the fiber improves the failure form of the concrete specimens, and 0.1% fiber content maximizes the compactness of the concrete. The flexural strength of specimen C2 with 0.1% fiber shows the highest strength obtained herein after freeze–thaw cycling, and the water absorption of specimen C2 is also the lowest after dry–wet cycling. The results also indicate that increasing the fiber volume content improves the freeze–thaw resistance of the concrete in a chloride environment. Chlorine ions migrate with the moisture during dry–wet and freeze–thaw cycling. The chlorine ion diffusion coefficient (Dcl) increases with increasing fiber content, except for that of specimen C2 in a chloride environment. The Dcl during freeze–thaw cycling is much higher than that during dry–wet cycling.

Determination of Technological Forces in the Incremental Forming Process

2013 ◽  
Vol 371 ◽  
pp. 133-137
Author(s):  
Radu Eugen Breaz ◽  
Melania Tera ◽  
Octavian Bologa ◽  
Sever Gabriel Racz
Keyword(s):  
Image Processing ◽  
Theoretical Model ◽  
Data Acquisition ◽  
Incremental Forming ◽  
Single Point ◽  
Cnc Milling ◽  
Forming Process ◽  
Feed Drive ◽  
Cnc Milling Machine

The paper presents a joint theoretical and experimental approach to determine the technological forces within the asymmetric single point incremental forming ASPIF process, based upon a theoretical model, image processing and data acquisition. The first step of this approach was to develop a theoretical model of the forces within the process, based upon the model of a mechanical feed drive of a CNC milling machine. By means of this model, relationships between the resistant torque at the motor spindle level and the technological force on the movement axis could be determined. Using an image processing method, which allowed the user to extract information within the machines operator panel and analytical relationships, the technological forces were determined. The results were compared with the measured values, obtained by means of a data acquisition system.

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