scholarly journals Billet Straightening by Three-Point Bending and Its Automation

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 90
Author(s):  
Radim Halama ◽  
Jan Sikora ◽  
Martin Fusek ◽  
Jaromír Mec ◽  
Jana Bartecká ◽  
...  
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Finite Element Simulations ◽  
Parameters Estimation ◽  
Three Point Bending ◽  
Material Parameters ◽  
New Material ◽  
Basic Ideas

This paper presents the current results of cooperation focused on automatic billet straightening machine development. First, an experimental study of three-point bending realized on small specimens is presented to explain the basic ideas of the straightening. Then, the main regimes of straightening and the algorithm itself are described together. Subsequent finite element simulations of operational experiments show the applicability of the developed theory. The significance of material parameters estimation is depicted in this work. At least four parameters have to be properly determined for a new material in the straightening process.

ESTABLISHMENT AND APPLICATION OF LOWER LIMB FINITE ELEMENT MODEL BASED ON MUSCLE GROUPS

2018 ◽  
Vol 18 (08) ◽  
pp. 1840024
Author(s):  
MONAN WANG ◽  
RONGPENG LI ◽  
JUNTONG JING
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Finite Element Model ◽  
Lower Limb ◽  
Element Model ◽  
Upper And Lower Bounds ◽  
Three Point Bending ◽  
Living Body ◽  
Prosthetic Socket ◽  
Simulation Results

Living body or corpse could be replaced with the virtual human tissue model for biomechanical experimental study, which effectively avoids the non-reusability, great social controversy, huge costs and difficulty in extracting parameters, and finally, the accurate analysis results are obtained. Unlike the previous lower limb models, the finite element models of hip and thigh were established based on the concept of muscle group in this paper. The cortical bones of hip bone and femur were set as *MAT_PIECEWISE_LINEAR_ PLASTICITY. The material of cancellous bone was set as *MAT_ELASTIC_PLASTIC_ WITH_DAMAGE_FAILURE. The material of articular cartilage was set as *MAT_ISOTROPIC_ELASTIC. The materials of muscle and fat were set as *MAT_VISCOELASTIC. The accuracy of the finite element model was verified by dynamic three-point bending experiment of the thighs. Mechanical simulation was carried out to the stump-prosthetic socket and the comfort of socks by the established model. The simulation results were all between the upper and lower bounds of the experimental results in the dynamic three-point bending experiment of the thighs where the loads were separately applied to one-third of the distal end of thighs and the middle part of thighs. The simulation results of the stump-prosthetic socket example show that the optimal elastic modulus of silicone pad is 2.5[Formula: see text]MPa. Simulation results of socks comfort show that the distribution of stress and deformation of the anterior and posterior thighs is different when the human lower limbs are in stockings. The established simulation model meets the accuracy requirement and can replace the living body or corpse to carry out biomechanical experimental study. The finite element simulation results converge, and the time to complete a finite element calculation is less than or equal to 10[Formula: see text]min.

scholarly journals Modelling of Size Effect with Regularised Continua

10.14311/612 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
H. Askes ◽  
A. Simone ◽  
L. J. Sluys
Keyword(s):  
Finite Element ◽  
Size Effect ◽  
Size Effects ◽  
Finite Element Simulations ◽  
Nonlocal Damage ◽  
Three Point Bending ◽  
Nominal Strength ◽  
Model Size ◽  
Numerical Finite Element

A nonlocal damage continuum and a viscoplastic damage continuum are used to model size effects. Three-point bending specimens are analysed, whereby a distinction is made between unnotched specimens, specimens with a constant notch and specimens with a proportionally scaled notch. Numerical finite element simulations have been performed for specimen sizes in a range of 1:64. Size effects are established in terms of nominal strength and compared to existing size effect models from the literature. 

Bending Properties of Laser Welded Web-Core Steel Sandwich Plates

2014 ◽  
Vol 936 ◽  
pp. 1451-1455 ◽  
Author(s):  
Xiao Xia Jiang ◽  
Liang Zhu ◽  
Ji Sen Qiao ◽  
Yi Xiong Wu ◽  
Zhu Guo Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Sandwich Plate ◽  
Finite Element Simulations ◽  
Bending Test ◽  
Sandwich Plates ◽  
Bending Properties ◽  
Three Point Bending ◽  
Weld Width ◽  
The Core ◽  
Good Agreement

This paper presents a detailed discussion of the bending properties of laser welded web-core steel sandwich plates and the influence of weld width on stiffness and strength. The over-hanging three point bending test was conducted on the laser welded web-core steel sandwich plates with various welds width by self-designed device, together with the finite element simulations. A good agreement is obtained between the 2D FE analyses and experiment results. The stiffness and strength of the sandwich plates increased with the increasing of weld width, especially for the weld width lower than 60% thickness of the core plate. It is necessary to consider the weld width in the design and evaluation of the stiffness and strength of the laser welded web-core sandwich plate. Base on the results, the FEM is the priority to analysis bending properties of laser welded web-core steel sandwich plates.

scholarly journals Effect of compaction roller on layup quality and defects formation in automated fiber placement

2019 ◽  
Vol 39 (1-2) ◽  
pp. 3-20 ◽  
Author(s):  
Nima Bakhshi ◽  
Mehdi Hojjati
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Pressure Distribution ◽  
Finite Element Simulations ◽  
Process Conditions ◽  
Fiber Placement ◽  
Static Testing ◽  
Contact Width ◽  
Automated Fiber Placement

Application of automated fiber placement is limited by defects formed in the prepreg tows during the layup process. An extensive experimental study is performed to investigate the effect of compaction roller on the quality of the layup. Five different compaction rollers with different stiffness and architectures were manufactured and employed to dispense prepreg tows at various process conditions. Layup quality was examined and different defects including tow buckling and blister were identified. In addition to automated fiber placement trials, static testing and finite element simulations were performed to probe the pressure distribution and contact width of each roller. This data was used to support and understand the results of the automated fiber placement trials. Results indicate the solid elastomer rollers that are compliant enough to produce the same level of contact width under similar levels of compaction forces are superior to the perforated rollers in terms of achievable layup quality.

FEM Analysis of Small Punch Tests

2017 ◽  
Vol 734 ◽  
pp. 23-36 ◽  
Author(s):  
Martin Abendroth
Keyword(s):  
Finite Element ◽  
Optimization Techniques ◽  
Finite Element Simulations ◽  
Test Method ◽  
Attractive Alternative ◽  
Material Models ◽  
Small Punch ◽  
Testing Procedures ◽  
Material Parameters ◽  
Deformation State

In recent years the small punch test method has become an attractive alternative compared to traditional material testing procedures, especially in cases where only small amounts of material are available. In contrast to standard test methods, the relevant material parameters can not be as simply obtained from the experimental measurements of SPTs because of its non-uniform stress and deformation state. However this can be achieved by comparing the experimental SPT results with those obtained by finite element simulations of SPT using advanced material models. Then the task is to determine the parameters of the material models using special optimization techniques. This paper gives an overview about the common techniques used to simulate SPT experiments. It should give the reader answer to the questions: Why are FEM simulations useful? How should such simulations be performed? Which material laws can be used? What are the limitations of finite element simulations? How to determine material parameters from SPT-experiments and the corresponding simulations?

scholarly journals On the Influence of Material Parameters in a Complex Material Model for Powder Compaction

2016 ◽  
Vol 25 (10) ◽  
pp. 4408-4415 ◽  
Author(s):  
Hjalmar Staf ◽  
Per Lindskog ◽  
Daniel C. Andersson ◽  
Per-Lennart Larsson
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Continuum Mechanics ◽  
Material Model ◽  
Sensitivity Study ◽  
Powder Compaction ◽  
Finite Element Simulations ◽  
Complex Material ◽  
Material Parameters ◽  
Wide Range

Abstract Parameters in a complex material model for powder compaction, based on a continuum mechanics approach, are evaluated using real insert geometries. The parameter sensitivity with respect to density and stress after compaction, pertinent to a wide range of geometries, is studied in order to investigate completeness and limitations of the material model. Finite element simulations with varied material parameters are used to build surrogate models for the sensitivity study. The conclusion from this analysis is that a simplification of the material model is relevant, especially for simple insert geometries. Parameters linked to anisotropy and the plastic strain evolution angle have a small impact on the final result.

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