scholarly journals Increase in Warpage Prediction Accuracy for Glass Filled Polyamide Material (PA66) through Integrative Simulation Approach

2021 ◽  
Vol 15 ◽  
pp. 1-9
Author(s):  
Vivek Ramdas Gaval ◽  
M Divekar ◽  
A Wonisch ◽  
G Jadhav
Keyword(s):  
Mechanical Properties ◽  
Prediction Accuracy ◽  
Material Model ◽  
Thermomechanical Properties ◽  
Simulation Software ◽  
Experimental Results ◽  
Manufacturing Cost ◽  
Simulation Approach ◽  
Nonlinear Mechanical ◽  
New Material

The warpage prediction accuracy of the simulation software depends on part geometry, material model and methodology. However, the material model in the existing simulation software’s does not consider factors such as nonlinear mechanical properties, temperature dependent behaviour, viscoelastic behaviour and transient description of warpage leading to less accuracy. Using an integrative simulation approach, BASF has developed Ultrasim® tool to overcome limitations in the material model of existing simulation software. In the new material model thermomechanical properties, stress relaxation behaviour and nonlinear mechanical properties were considered and this new material model is added to Ultrasim® tool. The model also considers time dependent descriptions of the warpage starting from packing phase of the moulding process, followed by actual ejection and cooling. In this paper warpage results predicted through new integrative simulation approach and existing simulation approach are compared with actual experimental results for 50% glass filled polyamide material (Ultramid®A3WG10). The results revealed that warpage values predicted by integrative simulation based Ultrasim® tool are closer to actual experimental results compared to values predicted by existing simulation technologies. Therefore an integrative simulation approach can be used prior to making real parts to reduce manufacturing cost.

A Comparison of 1D-3D Co-Simulation and Transient 3D Simulation for EGR Distribution Studies

2016 ◽  
Author(s):  
P. Dimitriou ◽  
C. Avola ◽  
R. Burke ◽  
C. Copeland ◽  
N. Turner
Keyword(s):  
Cfd Simulation ◽  
Simulation Software ◽  
Experimental Results ◽  
3D Simulation ◽  
Convergence Time ◽  
Simulation Approach ◽  
Mesh Quality ◽  
Time Step ◽  
1D Model ◽  
Simulation Time

Computational modeling, an important task for design, research and development stages, is evolving fast with the increase of computational capabilities over the last decades. One-dimensional (1D) CFD simulation is commonly used to analyze the flow rates and pressures of an entire fluid system of interconnected parts such as pipes, junctions, valves, and pumps. In contrast, three-dimensional (3D) CFD simulation allows detailed modeling of components such as manifolds, heat exchangers, and combustion cylinders where the flow contains significant 3D effects. Coupling a 1D model with a 3D domain potentially offers the benefits of both simulation strategies in one co-simulation approach. The present study provides a deep understanding of the co-simulation approach by listing all necessary steps need to be followed before and during the coupling of the 1D and 3D simulation software. It analyses the simulation and convergence time requirements based on the 3D model mesh quality and compares this approach with the current 1D–3D uncoupled approach followed in the industry. The outputs of both simulation approaches are then compared with experimental results. The co-simulation time mainly depends on the mesh quality of the 3D domain and the number of inner iterations per time-step which is entirely determined by the nature and complexity of the simulation. The co-simulation time per engine cycle is almost identical to the uncoupled approach. However, it was found that the number of cycles required for convergence in the coupled approach is nearly double than the uncoupled approach. The comparison between the two simulation approaches and the experimental results demonstrated the very 3D nature of the flows, the sensitivity of the uncoupled approach to input conditions and the sensitivity of co-simulation to the averaged boundary conditions transferred from the 1D model back to the 3D domain.

Refined Numerical Simulation and Experimental Investigation on Arc Welded Joints of 6061 Aluminum Alloy

2011 ◽  
Vol 314-316 ◽  
pp. 894-899
Author(s):  
Qiang Liu ◽  
Jing Bing Li ◽  
Zhi Jian Zong
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Welded Joints ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
Solid Model ◽  
Simulation Approach ◽  
Simulation Accuracy ◽  
6061 Aluminum Alloy

In order to improve the simulation accuracy for arc welded structures, the refined numerical simulation approach using the solid model with material mechanical properties has been presented. The arc welded joints are frequently utilized in the manufacture of neighborhood electric vehicle. Firstly, the mechanical properties of the base metal and three types of welded joints were determined by the uniaxial tensile experiments, and experimental results revealed that the mechanical property significantly reduced after welding. Then the numerical simulation approach using solid model and approach using weld constraint were conducted on the butt welded joints of 6061 aluminum alloy in LS-DYNA software, the simulation results were compared with experimental results. Moreover, the refined simulation approach using solid model was validated by different types of arc welded joints and their corresponding experiments. It is concluded that the proposal simulation approach using solid model shows higher accuracy than the approach using weld constraint on predicting deformation of butt welded and fillet welded joints.

Improvement of warpage prediction through integrative simulation approach for thermoplastic material

2020 ◽  
pp. 089270572093074
Author(s):  
Mahesh Divekar ◽  
Vivek R Gaval ◽  
Andreas Wonisch
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Material Model ◽  
Simulation Method ◽  
Simulation Approach ◽  
Polybutylene Terephthalate ◽  
Temperature Dependent ◽  
Actual Measurement ◽  
Molded Parts ◽  
Moldflow Simulation

In the injection-molded parts, prediction of accurate warpage at initial level becomes mandatory to avoid iterative work of mold modifications. Simulation teams of many organizations are using existing commercial programs for process simulations. Material models in existing simulation technologies are having certain limitations and assumptions, which can regularly result in up to 50% variation of warpage results as compared to the actual physical warpage measurement. The commonly used Moldflow simulation model, for example, ignores temperature-dependent mechanical properties and the stress relaxation spectrum for viscoelastic materials. These assumptions affect the accuracy of the warpage prediction results significantly. To decrease these kinds of variations, BASF extended its Ultrasim® tool which is based on integrative simulation technology. Recently, a newly developed thermomechanical material model with temperature-dependent nonlinear mechanical properties and stress relaxation behavior was added in the Ultrasim. This model has been used in this work to consider the complete transient description of the warpage, which starts at packing phase of the part inside the mold, followed by actual cooling and ejection. In this article, unreinforced semicrystalline polybutylene terephthalate polymer material (Ultradur® B4520) is considered for warpage correlational study. The accuracy of the warpage prediction is compared between the integrative simulation approach, existing warpage simulation method, and the actual experimental inspection results. The result exhibits that the accuracy of the integrative simulation (Ultrasim)-based warpage simulation is relatively better than existing simulation technologies and closer to the actual measurement.

Research on Compression Mechanical Properties of Metal-Net Rubber

2016 ◽  
Vol 858 ◽  
pp. 179-183
Author(s):  
Yi Ming Su ◽  
Ying Hou ◽  
Guang Ping Zou
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Relative Density ◽  
Compression Test ◽  
Wire Diameter ◽  
Static Compression ◽  
Nonlinear Mechanical ◽  
Metal Rubber ◽  
New Material ◽  
The Wire

For the study of the metal-rubber which is a new material used as damper component. The compression mechanical properties of metal-net rubber were studied. Through the static compression test of metal-net rubber, the influence of some factors such as: compression amount, relative density, wire diameter and bearing area. The method is variable-controlling. Experimental results show that along with the increase of the amount of compression, the nonlinear mechanical properties of metal-net rubber boosts; with the increase of relative density, the compressive capacity of metal-net rubber improves. The wire diameter influences the nonlinear mechanical properties of metal-net rubber, the larger the wire diameter, the compressive capacity is higher; the bearing area is greater, the compressive capacity and energy dissipation performance are better.

Combined Densification and Thermo-Hydro-Mechanical Processing of Wood

MRS Bulletin ◽  
2004 ◽  
Vol 29 (5) ◽  
pp. 332-336 ◽  
Author(s):  
Parviz Navi ◽  
Frédéric Heger
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Experimental Results ◽  
Densified Wood ◽  
Mechanical Processing ◽  
Shape Memory Effects ◽  
New Material ◽  
Potential Use

AbstractThe process of heating and compressing wood to improve its properties or reform it to a new shape has been known for decades. Such improvements are usually accompanied by “shape memory,” where the deformation produced by compression is not permanent, and the material recovers when re-moistened and heated. The combination of densification and a thermo-hydro-mechanical (THM) treatment can transform wood into a new material with improved mechanical properties, decreased sensitivity to moisture, increased durability, and no shape-memory effects. This article presents the principles of combined densification and THM processing, the products and experimental results, the origin of the shape-memory effect and its elimination by THM treatment, and the potential use of THM-processed densified wood in construction applications.

Application of the Finite Element Method in Screening of Body Turn up Heights for Radial Truck Tires

2001 ◽  
Vol 29 (3) ◽  
pp. 186-196 ◽  
Author(s):  
X. Yan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Material Model ◽  
The Finite Element Method ◽  
Truck Tires ◽  
Contact Constraint ◽  
Nonlinear Mechanical ◽  
Critical Regions ◽  
Constraint Method ◽  
Element Method

Abstract A method is described to predict relative body turn up endurance of radial truck tires using the finite element method. The elastomers in the tire were simulated by incompressible elements for which the nonlinear mechanical properties were described by the Mooney-Rivlin model. The belt, carcass, and bead were modeled by an equivalent orthotropic material model. The contact constraint of a radial tire structure with a flat foundation and rigid rim was treated using the variable constraint method. Three groups of tires with different body turn up heights under inflation and static footprint loading were analyzed by using the finite element method. Based on the detail analysis for stress analysis parameters in the critical regions in the tires, the relative body turn up edge endurance was predicted.

scholarly journals Effects of Steel Fiber Percentage and Aspect Ratios on Fresh and Harden Properties of Ultra-High Performance Fiber

2021 ◽  
Vol 2 (3) ◽  
pp. 501-515
Author(s):  
Rajib Kumar Biswas ◽  
Farabi Bin Ahmed ◽  
Md. Ehsanul Haque ◽  
Afra Anam Provasha ◽  
Zahid Hasan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
High Performance ◽  
Steel Fiber ◽  
Setting Time ◽  
Fiber Reinforced Concrete ◽  
Future Research ◽  
Manufacturing Cost ◽  
Aspect Ratios ◽  
High Performance Fiber

Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.

scholarly journals Performance of SCAN Meta-GGA Functionals on Nonlinear Mechanics of Graphene-Like g-SiC

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 120
Author(s):  
Qing Peng
Keyword(s):  
Mechanical Properties ◽  
Density Functional ◽  
Large Strains ◽  
Two Dimensional ◽  
Nonlinear Mechanics ◽  
Generalized Gradient ◽  
Mechanics Of Materials ◽  
Nonlinear Mechanical ◽  
Direct Band ◽  
Simulations And Modeling

Although meta-generalized-gradient approximations (meta-GGAs) are believed potentially the most accurate among the efficient first-principles calculations, the performance has not been accessed on the nonlinear mechanical properties of two-dimensional nanomaterials. Graphene, like two-dimensional silicon carbide g-SiC, has a wide direct band-gap with applications in high-power electronics and solar energy. Taken g-SiC as a paradigm, we have investigated the performance of meta-GGA functionals on the nonlinear mechanical properties under large strains, both compressive and tensile, along three deformation modes using Strongly Constrained and Appropriately Normed Semilocal Density Functional (SCAN) as an example. A close comparison suggests that the nonlinear mechanics predicted from SCAN are very similar to that of Perdew-Burke-Ernzerhof (PBE) formulated functional, a standard Density Functional Theory (DFT) functional. The improvement from SCAN calculation over PBE calculation is minor, despite the considerable increase of computing demand. This study could be helpful in selection of density functionals in simulations and modeling of mechanics of materials.

scholarly journals Internal constraints and arrested relaxation in main-chain nematic elastomers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takuya Ohzono ◽  
Kaoru Katoh ◽  
Hiroyuki Minamikawa ◽  
Mohand O. Saed ◽  
Eugene M. Terentjev
Keyword(s):  
Mechanical Properties ◽  
Main Chain ◽  
Polymer Networks ◽  
Nematic Order ◽  
Nematic Elastomers ◽  
Nematic Director ◽  
Highly Nonlinear ◽  
Nonlinear Mechanical ◽  
Liquid Crystal Elastomers ◽  
Memory Applications

AbstractNematic liquid crystal elastomers (N-LCE) exhibit intriguing mechanical properties, such as reversible actuation and soft elasticity, which manifests as a wide plateau of low nearly-constant stress upon stretching. N-LCE also have a characteristically slow stress relaxation, which sometimes prevents their shape recovery. To understand how the inherent nematic order retards and arrests the equilibration, here we examine hysteretic stress-strain characteristics in a series of specifically designed main-chain N-LCE, investigating both macroscopic mechanical properties and the microscopic nematic director distribution under applied strains. The hysteretic features are attributed to the dynamics of thermodynamically unfavoured hairpins, the sharp folds on anisotropic polymer strands, the creation and transition of which are restricted by the nematic order. These findings provide a new avenue for tuning the hysteretic nature of N-LCE at both macro- and microscopic levels via different designs of polymer networks, toward materials with highly nonlinear mechanical properties and shape-memory applications.

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