Mechanics of Composite Layered Rough Medium in Contact

2013 ◽  
Vol 703 ◽  
pp. 200-203
Author(s):  
Shao Biao Cai ◽  
Yong Li Zhao
Keyword(s):  
Material Properties ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Normal Loading ◽  
Layered Coatings ◽  
Pressure Profiles ◽  
Tangential Traction ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Tangential Friction

This study presents a first attempt to develop a numerical three-dimensional multilayered (more than 2 composite layered coatings) elasticperfectly plastic rough solids model to investigate the contact behavior under combined normal loading and tangential traction. Contact analyses are performed to study the effects composite thin film layers. Local contact pressure profiles, von Mises stresses, and shear stresses as a function of material properties and applied normal and tangential friction loads are calculated.

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.

A Feasibility Investigation on Improving Structural Integrity of Thermoelectric Modules With Varying Geometry

2012 ◽  
Author(s):  
Ugur Erturun ◽  
Karla Mossi
Keyword(s):  
Power Generation ◽  
Material Properties ◽  
Thermal Stresses ◽  
Structural Integrity ◽  
Temperature Dependent ◽  
Thermoelectric Modules ◽  
Geometry Model ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Ansys Workbench

This study investigates the feasibility of improving the structural integrity of thermoelectric modules (TEMs) with varying geometry. For this purpose, six different TEM models with various thermoelectric leg geometries were designed and modeled in order to perform a thermal stress FEA using ANSYS Workbench. Temperature dependent material properties were used since some properties such as coefficients of thermal expansion change with temperature. Significant decrease in thermal stresses and leg deformations were observed with some models. Particularly, the cylindrical TE leg geometry model has approximately 54% lower Von Mises stresses (294MPa) and 13% lower TE leg deformations (3.9μm) than those of the typical TE leg geometry model (635MPa and 4.5μm). Power generation analyses of the models were performed to evaluate the effect of new TE leg geometries on the performance. TEM model with cylindrical TE leg geometry has the highest power generation (29.3mW) among all the models.

scholarly journals Effect of Augmentation Material Stiffness on Adjacent Vertebrae after Osteoporotic Vertebroplasty Using Finite Element Analysis with Different Loading Methods

2015 ◽  
Vol 6;18 (6;11) ◽  
pp. E1101-E1110
Author(s):  
Ah-Reum Cho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Cement ◽  
Vertebral Fractures ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Adjacent Vertebral Body ◽  
Von Mises ◽  
Von Mises Stresses

Background: Vertebroplasty is an effective treatment for osteoporotic vertebral fractures, which are one of the most common fractures associated with osteoporosis. However, clinical observation has shown that the risk of adjacent vertebral body fractures may increase after vertebroplasty. The mechanism underlying adjacent vertebral body fracture after vertebroplasty is not clear; excessive stiffness resulting from polymethyl methacrylate has been suspected as an important mechanism. Objectives: The aim of our study was to compare the effects of bone cement stiffness on adjacent vertebrae after osteoporotic vertebroplasty under load-controlled versus displacementcontrolled conditions. Study Design: An experimental computer study using a finite element analysis. Setting: Medical research institute, university hospital, Korea. Methods: A three-dimensional digital anatomic model of L1/2 bone structure was reconstructed from human computed tomographic images. The reconstructed three-dimensional geometry was processed for finite element analysis such as meshing elements and applying material properties. Two boundary conditions, load-controlled and displacement-controlled methods, were applied to each of 5 deformation modes: compression, flexion, extension, lateral bending, and torsion. Results: The adjacent L1 vertebra, irrespective of augmentation, revealed nearly similar maximum von Mises stresses under the load-controlled condition. However, for the displacementcontrolled condition, the maximum von Mises stresses in the cortical bone and inferior endplate of the adjacent L1 vertebra increased significantly after cement augmentation. This increase was more significant than that with stiffer bone cement under all modes, except the torsion mode. Limitations: The finite element model was simplified, excluding muscular forces and incorporating a large volume of bone cement, to more clearly demonstrate effects of bone cement stiffness on adjacent vertebrae after vertebroplasty. Conclusion: Excessive stiffness of augmented bone cement increases the risk of adjacent vertebral fractures after vertebroplasty in an osteoporotic finite element model. This result was most prominently observed using the displacement-controlled method. Key words: Bone cements, displacement-controlled method, finite element analysis, loadcontrolled method, osteoporosis, osteoporotic fracture, polymethyl methacrylate, vertebroplasty

scholarly journals Análise numérica de ligação parafusada semirrígida em perfis formados a frio

ForScience ◽  
2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Emerson Cardoso de Castro ◽  
Flávio Teixeira de Souza ◽  
Arlene Maria Cunha Sarmanho
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Finite Elements ◽  
Three Dimensional ◽  
Structural Performance ◽  
Similar Tendency ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Bolt Connection ◽  
Force Displacement

O presente trabalho constitui-se de uma análise numérica, por meio de elementos finitos, objetivando a reprodução via software de um ensaio experimental de ligação parafusada semirrígida em perfis formados a frio, dada no âmbito tridimensional. A análise consistiu-se a partir da reprodução da geometria do protótipo, das condições de contorno e aplicação de carregamento. Para melhor previsão do comportamento da ligação, foram inseridas ao modelo a não linearidade física e geométrica. Foram obtidas as curvas força-deslocamento e a evolução das tensões de Von Mises para os diferentes componentes do protótipo. Os resultados indicaram que o modelo numérico é cerca de duas vezes mais rígido que o experimental. Todavia, foi possível observar que o comportamento do modelo numérico possui tendência similar ao do modelo experimental e também foi possível avaliar a contribuição dos elementos da ligação para o desempenho da mesma.Palavras-chave: Análise numérica. Ligação parafusada semirrígida. Perfis formados a frio. Desempenho estrutural.Numerical analysis of semi-rigid bolt connection in cold formed profilesAbstractThe current paper is based on a numerical analysis by means of finite elements aiming at the software reproduction of an experimental test of semi-rigid bolt connection in cold formed profiles occurred in the three-dimensional scope. The analysis consisted of the reproduction of the prototype geometry, the boundary conditions, and the loading application. For a better forecast of the connection behavior, physical and geometric non-linearity were inserted to the model. The force-displacement curves and the evolution of the Von Mises stresses for the different prototype components were obtained. The results indicated that the numerical model is about twice as rigid as the experimental one. However, it was possible to observe that the behavior of the numerical model has a similar tendency  if compared to  the experimental model and it was still possible to evaluate the contribution of the connection elements to its performance.Keywords: Numerical analysis. Semi-rigid bolt connection. Cold-formed profiles. Structural performance.

scholarly journals DESCRIBING STRESS CONCENTRATION FACTORS OF AN INTERNALLY PRESSURIZED CYLINDER WITH AN IMBEDDED HOLE BY NEW FORMULATION

2020 ◽  
Author(s):  
javad jafari fesharaki
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Internal Diameter ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
New Formulation ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Pressurized Cylinder

The purpose of this paper is to investigate the stress concentration factor(SCF) for an internallypressurized cylinder with hole and based on detailed three-dimensional elastic FE analysis, a newcomprehensive set of formulas for SCFs are proposed. These stress concentration factors are presentedand discussed as a function of the ratio of cylinder diameter to the thickness of cylinder and hole diameter.The first ratio “D/100t” is equal to 1, 1.25, 1.5, 1.75, 2, 2.5, 2.75, 3, 3.25 and 3.5 and the second ratio“D/10d”, cylinder internal diameter to the hole diameter, varies from 0.6, 0.9, 1.2, 1.5, 1.8, 2, 2.3, 2.7,3.1and 3.5. Results are also presented for SCF of longitudinal, circumferential and Von Mises stresses.

scholarly journals Stress distribution in a mandibular premolar after separated nickel-titanium instrument removal and root canal preparation: a three-dimensional finite element analysis

2019 ◽  
Vol 47 (4) ◽  
pp. 1555-1564 ◽  
Author(s):  
Na Ni ◽  
Jing Ye ◽  
Liyuan Wang ◽  
Simin Shen ◽  
Lei Han ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Cervical Region ◽  
Element Analysis ◽  
Straight Line ◽  
Mandibular First Premolar ◽  
Von Mises ◽  
Von Mises Stresses

Objective This study used finite element analysis (FEA) to assess the von Mises stresses of a mandibular first premolar after removing a separated instrument with an ultrasonic technique. Methods FEA models of the original and treated mandibular first premolar were reconstructed, and three models (the original canal, size 30/taper 0.04 canal, and separated instrument removal canal) were created. Two-direction (vertical and lateral) loading patterns were simulated with a 175-N force. The maximum von Mises stresses of the models within the roots from the apex to the cervical region were collected and summarized. Results Under vertical and lateral loads, all maximal values in the three models were localized in the straight-line access region. Compared with the original model (model 1), the treated models (models 2 and 3) had greater maximum stress values from the apex to the cervical region. Greater differences in the maximum von Mises stresses between models 2 and 3 were present in the straight-line access region. Conclusions Separated instrument removal caused changes in stress distribution and increases in stress concentration in the straight-line access region of roots.

Finite Element Analysis of Automotive Disk Brake and Pad in Frictional Model Contact

2015 ◽  
Vol 5 (4) ◽  
pp. 32-62 ◽  
Author(s):  
Belhocine Ali
Keyword(s):  
Computer Code ◽  
Shear Stresses ◽  
Good Prediction ◽  
Element Analysis ◽  
Disk Brake ◽  
Mechanical Study ◽  
Dry Contact ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Braking Phase

The object of this work is to present a study of the thermomechanical behavior of the automobile disc brake during the braking phase. Then, a purely mechanical study of dry contact between the disc and pads is developed with a good prediction becomes a major stake for the industrialists while modeling the loading and the boundary conditions around the disc. The same computer code was used to visualize displacements, total deformations in the disc, shear stresses, Von Mises stresses and, the tools of contact pads. Also studied was the case of thermoelasticity while interpreting the various exits results during this simulation.

Deformations and Stresses in Soft Body Tissues of a Sitting Person

1978 ◽  
Vol 100 (2) ◽  
pp. 79-87 ◽  
Author(s):  
W. W. Chow ◽  
E. I. Odell
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Surface Friction ◽  
Element Model ◽  
The Finite Element Method ◽  
Decubitus Ulcers ◽  
Surface Pressure Distribution ◽  
Body Tissues ◽  
Von Mises ◽  
Von Mises Stresses

This paper investigates the deformations and stresses in the buttocks of a person when he sits on a cushion. The study is motivated by the need for a better understanding of the design of wheelchair cushions and the prevention of decubitus ulcers. The finite element method is used on an axisymmetric model. Surface pressure distribution, surface friction, hydrostatic pressures and von Mises stresses are obtained. The finite element model reveals the three-dimensional state of stress at all internal locations for a typical human body. Thus the study complements the experimental measurements performed by many physicians and bioengineers.

scholarly journals Optimisation of stress distribution in a highly loaded radial-axial gas microturbine using FEM

2020 ◽  
Vol 10 (1) ◽  
pp. 318-335 ◽  
Author(s):  
Paweł Zych ◽  
Grzegorz Żywica
Keyword(s):  
Stress Reduction ◽  
High Speed ◽  
Three Dimensional ◽  
Design Stage ◽  
Industrial Sectors ◽  
Reduction Methods ◽  
Scientists And Engineers ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Highly Loaded

AbstractThe article discusses the stress optimisation process of the highly loaded disc of a high-speed radial-axial microturbine. At the design stage, the strength optimisation is vitally important for these types of devices because they must withstand very high temperatures (600∘C in this case) and be capable of operating at high rotational speeds (96,000 rpm in this case). Calculations were made using a three dimensional FE numerical model. The optimisation process is strictly connected with the choice of materials — which in this case are Inconel 738 (nickel-cobalt super alloy) and silicon nitride. Several stress reduction methods were developed, which took into account the mass of the disc, the rotational speed of the rotor and the complex shape of the rear part of the disc. Numerical computations helped to choose the best optimisation method, which decreased maximum reduced von Mises stresses by about 45% (from 1,288 MPa to 705 MPa). The methods proposed in this article are universal and can be implemented in the design process of various high-speed radial-axial microturbines. This article could be of interest to scientists and engineers who deal with highly loaded microturbines, which are increasingly used in many industrial sectors.

scholarly journals Finite Element Analysis Comparison of Plate Designs in Managing Fractures Involving the Mental Foramen

2013 ◽  
Vol 6 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Neralla Mahathi ◽  
Emmanuel Azariah ◽  
C. Ravindran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Mental Foramen ◽  
Stress Generation ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Plate Design ◽  
Von Mises ◽  
Von Mises Stresses

Introduction The aim of the study was to propose an ideal plating design for fractures running through the mental foramen. Methods The study compared three plating designs—two four-hole miniplates, 2 × 2-hole three-dimensional (3D) plate, and modified 2 × 2-hole 3D plate (posterior strut removed)—using finite element analysis. Von Mises stresses generated around the plates and bone were measured, as well as the mobility that is generated between the fracture fragments by applying muscle forces to generate bite force in one test and applying a force of 500 N over the premolars and first molar region in the second test. Results Von Mises stress in bone with miniplates measured 9.24 MPa in test 1 and 131.99 MPa in test 2. The stress with unmodified 3D plates measured 34.9 MPa in test 1 and150.03 MPa in test 2. The stress with modified 3D plates measured 24.98 MPa in test 1 and 150.59 MPa in test 2. Von Mises stress on the plates and screws measured 28.23 MPa, 95.97 MPa, 72.93 MPa in test 1 and 458.63 MPa, 779.01 MPa, 742.39 MPa in test 2 on miniplates, unmodified 3D plates, and modified 3D plates, respectively. The fracture mobility generated in the model with miniplates measured 0.001 mm in test 1 and 0.01 mm in test 2 and 0.007 mm and 0.02 mm in the model with unmodified 3D plates in test 1 and in test 2, respectively. In the model with modified 3D plates, the value was 0.001 mm and 0.01 mm in tests 1 and 2, respectively. Conclusion The ideal plate design is the two-plate technique with minimal stress generation on the bone and the hardware. The modified 3D plate has adequate strength to be used in the region but needs to be studied in detail.

Sign in / Sign up

Export Citation Format

Share Document