Finite Element Method and Parametric Study on Material Properties and Friction Coefficients for Design of Mechanical Components

2018 ◽  
Author(s):  
Yu Hua Li ◽  
Seung Ki Moon ◽  
Zhong Yang Chua ◽  
Teck Hui Ngo ◽  
Jun Jie Tou ◽  
...  
Keyword(s):  
Numerical Method ◽  
Material Properties ◽  
Parametric Study ◽  
Mechanical Efficiency ◽  
Von Mises Stress ◽  
Friction Coefficients ◽  
Air Compressor ◽  
Twin Screw ◽  
Von Mises ◽  
Screw Rotors

In this study, a parametric study on material properties and friction coefficient of mechanical components are investigated through simulating the real working conditions by a numerical method. As the screw rotors are the key components in an air compressor system, the rotors are exposed to complicated loading conditions during operation. The objective of this study is to investigate the effects on the input moment, peak Von Mises stress and the mechanical efficiency of the air compressor system subjected to varying parameters of the material properties of the female rotor and friction coefficients. From the simulation results, the peak Von Mises stress is greatly affected by the parameters of the material property of the female rotor, and the input moment and the mechanical efficiency are slightly influenced in the first condition. And, the peak Von Mises stress is significantly affected by the parameters of the friction coefficients, in the decreasing trend. The input moment is also increased with the increasing parameters of the friction coefficients. The mechanical efficiency is inversely correlated with the input moment, whereby efficiency is greatly reduced with an increase in input moment. The study shows that the proposed numerical method is efficient and suitable to establish the parameters study on the twin screw rotors, and provides an effective approach to investigate the twin screw rotors and improve the design of the system.

Analysis of Displacement-Controlled Fretting Between a Hemisphere and a Flat Block in Elasto-Plastic Contacts

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Material Properties ◽  
Large Range ◽  
Three Dimensional ◽  
Fretting Wear ◽  
Von Mises Stress ◽  
Partial Slip ◽  
Ductile Material ◽  
Element Analysis ◽  
Metallic Contact ◽  
Von Mises

This work employs a three-dimensional (3D) finite element analysis (FEA) to investigate the fretting metallic contact between a deformable hemisphere and a deformable flat block. Fretting is governed by displacement-controlled action where the materials of the two contacting bodies are set to have identical properties; studied first is steel-on-steel and then copper-on-copper. At contact onset, a normal interference (indentation) is applied, which is then followed by transverse cyclic oscillations. A large range of coefficients of friction (COFs) is imposed at the interface. The results show that the maximum von Mises stress is confined under the contacting surface for small COFs; however, that maximum reaches the contacting surface when the COFs are sufficiently large. It is also shown that fretting under sufficiently large COFs forms large plastic strains in “ring” like patterns at the contacting surfaces. Junction growth is found where the contacting region is being stretched in the direction of the fretting motion. At large COFs, pileups show up at the edges of the contact. The fretting loops of the initial cycles are found along with the total work invested into the system. At certain interference, there exists a certain COF, which results in the largest work consumption. The magnitude of the COF is found to produce either partial slip (prone for fretting fatigue) or gross slip (prone for fretting wear). A scheme of normalization is proposed, and it is shown to be effective for the two said materials that have vastly different material properties. Hence, the normalized results may well characterize a range of contact scales (from micro to macro) of various ductile material pairs that behave in an elastic–plastic manner with strain hardening.

Contact Analysis of a Soft-Coated Asperity During Loading–Unloading Process in Consideration of Strain Hardening Effects

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Yi Wang ◽  
Yi Cui ◽  
Shuo Liu ◽  
Xinhui Wang ◽  
Xinwei Tian ◽  
...  
Keyword(s):  
Power Law ◽  
Material Properties ◽  
Element Model ◽  
Von Mises Stress ◽  
Main Bearing ◽  
Plastic Properties ◽  
Medium Speed ◽  
Wide Range ◽  
Dimensional Finite Element ◽  
Von Mises

Abstract In this paper, the flattening process of a coated single asperity by a rigid flat is studied based on a two-dimensional finite element model under different contact interferences. The soft coating and hard substrate materials of the main bearing shell in a medium-speed vehicle diesel engine are both considered to follow the power-law hardening elastic-plastic properties. For both loading and unloading processes, the effects of geometrical and material properties, including the coating thickness, Young’s modulus, Poisson’s ratio, yielding stress, and hardening exponent, on the contact behaviors are studied in a wide range to cover the real material properties. The von Mises stress on the interface is also analyzed in order to improve the bonding strength between coating and substrate. The main contribution of this paper is to provide a method to determine the contact properties caused by different material and geometric properties of soft coating and substrate materials, which follow the power-law hardening properties.

Falling Simulation of Free-Standing Museum Cultural Relics Supported by Soft Pad

2014 ◽  
Vol 670-671 ◽  
pp. 715-719
Author(s):  
Qian Zhou
Keyword(s):  
Material Properties ◽  
Element Model ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Acceleration Response ◽  
Response Curves ◽  
Free Standing ◽  
Cultural Relic ◽  
Von Mises ◽  
Cultural Relics

Free-standing museum cultural relics are easy to fall off exhibition booth and get damaged under earthquakes. To find an effective method to mitigate damage of cultural relics due to fall off, influences of soft pad under relic was studied by ANSYS/LS-DYNA program. A bronze relic supported by a soft pad was selected for analysis. Based on material properties of both the relic and the pad, finite element model of the relic was built. By simulation, Von mises stress distributions, acceleration response curves as well as kinetic energy curves of the relic were obtained; effects of the soft pad to mitigate damage of the relic were discussed. Results show that collision between the falling museum cultural relic and ground can be mitigated by soft pad due to its buffer as well as energy absorption effects. It is suggested to use soft pad under relic to provide protection. Besides, by ANSYS/LS-DYNA program, falling off process of free-standing museum cultural relics can be effectively simulated.

scholarly journals Multi-layered bird beaks: a finite-element approach towards the role of keratin in stress dissipation

2012 ◽  
Vol 9 (73) ◽  
pp. 1787-1796 ◽  
Author(s):  
Joris Soons ◽  
Anthony Herrel ◽  
Annelies Genbrugge ◽  
Dominique Adriaens ◽  
Peter Aerts ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Speckle Pattern ◽  
Young Modulus ◽  
Von Mises Stress ◽  
Fe Model ◽  
Element Approach ◽  
Von Mises ◽  
The Impact

Bird beaks are layered structures, which contain a bony core and an outer keratin layer. The elastic moduli of this bone and keratin were obtained in a previous study. However, the mechanical role and interaction of both materials in stress dissipation during seed crushing remain unknown. In this paper, a multi-layered finite-element (FE) model of the Java finch's upper beak ( Padda oryzivora ) is established. Validation measurements are conducted using in vivo bite forces and by comparing the displacements with those obtained by digital speckle pattern interferometry. Next, the Young modulus of bone and keratin in this FE model was optimized in order to obtain the smallest peak von Mises stress in the upper beak. To do so, we created a surrogate model, which also allows us to study the impact of changing material properties of both tissues on the peak stresses. The theoretically best values for both moduli in the Java finch are retrieved and correspond well with previous experimentally obtained values, suggesting that material properties are tuned to the mechanical demands imposed during seed crushing.

Qualification of Water-Filled Tank due to Tornado Missile Impact

2016 ◽  
Author(s):  
Timothy A. Schmitt ◽  
Taha Al-Shawaf ◽  
Syed M. Rahman ◽  
Angelo Cristobal
Keyword(s):  
Material Properties ◽  
Impact Analysis ◽  
Impact Angle ◽  
Von Mises Stress ◽  
Empirical Formulas ◽  
Element Analysis ◽  
Fukushima Accident ◽  
Analysis And Design ◽  
Lower Elevation ◽  
Von Mises

As part of the post-Fukushima accident scenario, the qualification of a water-filled cylindrical tank subjected to tornado missile impact was required to ensure the availability of water inventory in the tank to mitigate the post-accident effects. Most of the classical tornado missile impact analysis and design involves using empirical formulas that have been developed based on tests. It is recognized that water backed structures provide additional resistance to perforation of the missile due to the mass and properties of the water. Therefore, a finite element analysis was used to qualify the tank for two controlling postulated missiles, namely, 2 ½” diameter schedule 40 pipe and bolted wood decking. The location on the tank for the missile impact, angle of impact and orientation of the missile were selected to develop the most critical response. The analysis was performed using the LS-DYNA computer program. The true stress-strain material properties were used for both the tank material and the missile types. These material properties were given a bilinear elastic-plastic curve. It was determined that, even if an impact at the thinnest section at the top of the tank occurs and the missile penetrates, the remaining inventory of water in the tank will be sufficient to mitigate the needs for a post-Fukushima scenario. Impact on the lower elevation of the tank was investigated for any potential failure or tearing of the tank wall. The maximum of equivalent (Von Mises) stress, shear stress, and plastic strain were calculated. The results show that these values are less than the limiting values with additional available margin. Consequently the analysis shows that the tank will survive a hit in the lower portions, and the water inventory of the tank is sufficient to mitigate the effect of a post-Fukushima scenario should a missile penetrate the thinner, upper section of the tank.

scholarly journals Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments

2020 ◽  
Vol 10 (11) ◽  
pp. 3858
Author(s):  
Diego Montoya-Zapata ◽  
Diego A. Acosta ◽  
Camilo Cortés ◽  
Juan Pareja-Corcho ◽  
Aitor Moreno ◽  
...  
Keyword(s):  
Design Of Experiments ◽  
Material Properties ◽  
Mechanical Response ◽  
Von Mises Stress ◽  
Local Geometry ◽  
Stress Strain ◽  
Strain Behavior ◽  
Compressive Loads ◽  
Von Mises ◽  
Large Domains

Lattice-based workpieces contain patterned repetition of individuals of a basic topology (Schwarz, ortho-walls, gyroid, etc.) with each individual having distinct geometric grading. In the context of the design, analysis and manufacturing of lattice workpieces, the problem of rapidly assessing the mechanical behavior of large domains is relevant for pre-evaluation of designs. In this realm, two approaches can be identified: (1) numerical simulations which usually bring accuracy but limit the size of the domains that can be studied due to intractable data sizes, and (2) material homogenization strategies that sacrifice precision to favor efficiency and allow for simulations of large domains. Material homogenization synthesizes diluted material properties in a lattice, according to the volume occupancy factor of such a lattice. Preliminary publications show that material homogenization is reasonable in predicting displacements, but is not in predicting stresses (highly sensitive to local geometry). As a response to such shortcomings, this paper presents a methodology that systematically uses design of experiments (DOE) to produce simple mathematical expressions (meta-models) that relate the stress–strain behavior of the lattice domain and the displacements of the homogeneous domain. The implementation in this paper estimates the von Mises stress in large Schwarz primitive lattice domains under compressive loads. The results of our experiments show that (1) material homogenization can efficiently and accurately approximate the displacements field, even in complex lattice domains, and (2) material homogenization and DOE can produce rough estimations of the von Mises stress in large domains (more than 100 cells). The errors in the von Mises stress estimations reach 42 % for domains of up to 24 cells. This result means that coarse stress–strain estimations may be possible in lattice domains by combining DOE and homogenized material properties. This option is not suitable for precise stress prediction in sensitive contexts wherein high accuracy is needed. Future work is required to refine the meta-models to improve the accuracies of the estimations.

Modal Analysis of Air Compressor Plate

2012 ◽  
Vol 466-467 ◽  
pp. 116-120
Author(s):  
Xiao Ying Li ◽  
Deng Feng Zhang ◽  
Xin Chun Wang
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Displacement Vector ◽  
Relative Displacement ◽  
Von Mises Stress ◽  
Air Compressor ◽  
First Order ◽  
Inherent Frequency ◽  
Von Mises ◽  
Fifth Order

In certain air compressor plate in the high speed revolving situation, based on the finite element theory, stress distribution in air compressor plate can be obtained. After the pre-stressed plate is carried on the modal analysis, fifth-order inherent frequency from first-order to fifth-order can be calculated out. After modal of compressor plate can be expanded, Relative deformed shape, relative displacement vector sum and relative Von Mises stress mode of compressor plate from first-order to fifth-order can be obtained.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

The Influence of Loading Position in A Priori High Stress Detection using Mode Superposition

2020 ◽  
Vol 1 (1) ◽  
pp. 93-102
Author(s):  
Carsten Strzalka ◽  
◽  
Manfred Zehn ◽  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
A Priori ◽  
High Stress ◽  
Von Mises Stress ◽  
Detailed Knowledge ◽  
Variable Loading ◽  
Numerical Effort ◽  
Von Mises

For the analysis of structural components, the finite element method (FEM) has become the most widely applied tool for numerical stress- and subsequent durability analyses. In industrial application advanced FE-models result in high numbers of degrees of freedom, making dynamic analyses time-consuming and expensive. As detailed finite element models are necessary for accurate stress results, the resulting data and connected numerical effort from dynamic stress analysis can be high. For the reduction of that effort, sophisticated methods have been developed to limit numerical calculations and processing of data to only small fractions of the global model. Therefore, detailed knowledge of the position of a component’s highly stressed areas is of great advantage for any present or subsequent analysis steps. In this paper an efficient method for the a priori detection of highly stressed areas of force-excited components is presented, based on modal stress superposition. As the component’s dynamic response and corresponding stress is always a function of its excitation, special attention is paid to the influence of the loading position. Based on the frequency domain solution of the modally decoupled equations of motion, a coefficient for a priori weighted superposition of modal von Mises stress fields is developed and validated on a simply supported cantilever beam structure with variable loading positions. The proposed approach is then applied to a simplified industrial model of a twist beam rear axle.

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