Boule Shape Dependence of Shear and von-Mises Stress Distributions in Bulk SiC during Sublimation Growth

2010 ◽  
Vol 1246 ◽  
Author(s):  
Roman Victorovich Drachev ◽  
Darren Hansen ◽  
Mark J Loboda
Keyword(s):  
Shear Stress ◽  
Thermal Conditions ◽  
Side Surface ◽  
Growth Front ◽  
Growth Conditions ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Reaction Cell ◽  
Small Seed ◽  
Von Mises

AbstractAn analytical study of the dependence of shear and von-Mises stress distributions, which develop during PVT (Physical Vapor Transport) growth of 4H-SiC, has been executed. The key parameters investigated include thermal conditions of the crystal growth and parameters of the growing boule geometry. The evaluation was conducted via a 24 full factorial DOE (Design of Experiments). Parameters of the growing boule geometry, i.e. seed diameter, growth front height, inclination angle and height of the side surface were set as the DOE factors, while responses were calculated using numerical simulations. It is found that unique SiC boule growth conditions, which simultaneously minimize both the shear stress and von Mises stress magnitudes, cannot be achieved. Optimization of the shear stress distribution favors longer SiC boules with small seed diameters, small expansion angles and flat growth fronts. Alternatively, optimization of von-Mises stress favors short crystals with small seed diameters and small expansion angles but with curved growth fronts. Consequently, optimization of stress components in SiC crystals involves careful investigation of the interaction and compromise of the reaction cell geometry and growth conditions.

Numerical Study on Elastic-Plastic Stress Field Near the Cooling Holes of Nickel-Based Single Crystal Air-Cooled Blades

2006 ◽  
Vol 324-325 ◽  
pp. 563-566 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Shear Stress ◽  
Stress Field ◽  
Numerical Study ◽  
Von Mises Stress ◽  
Shear Stresses ◽  
Slip Systems ◽  
Stress Distributions ◽  
Elastic Plastic ◽  
Von Mises ◽  
Plastic Stress

In this paper, a plate containing a central hole was used to simulate gas turbine blade with cooling hole. Numerical calculations based on crystal plasticity theory have been performed to study the elastic-plastic stress field near the hole under tension. Two crystallographic orientations [001] and [111] were considered. The distributions of resolved shear stresses and strains of the octahedral slip systems {110}<112> were calculated. The results show that the crystallographic orientation has remarkable influence on both von Mises stress and resolved shear stress distributions. The resolved shear stress distributions around the hole are different between the two orientations, which lead to the different activated slip systems. So the deformed shape of the hole in [001] orientation differs from that in [111] orientation.

scholarly journals Finite Element Analysis of Composite Repair for Damaged Steel Pipeline

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Jiaqi Chen ◽  
Hao Wang ◽  
Milad Salemi ◽  
Perumalsamy N. Balaguru
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Hoop Stress ◽  
Pipe Wall ◽  
Von Mises Stress ◽  
Repair System ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Von Mises ◽  
Infill Material

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

Investigation on stress distribution and pressure capacity of two-layer split high-pressure die based on finite element analysis

2019 ◽  
Vol 233 (14) ◽  
pp. 5048-5055
Author(s):  
Z Yi ◽  
WZ Fu ◽  
MZ Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress State ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Element Analysis ◽  
Round Cylinder ◽  
Von Mises ◽  
Supporting Ring

In order to obtain a higher pressure capacity for the high-pressure die with a larger sample cavity, two types of two-layer split dies with a round cylinder and a quadrate cylinder were designed based on the conventional belt-type die. Finite element analysis was performed to investigate the stress distributions and pressure capacities of the high-pressure dies using a derived Mohr–Coulomb criterion and the von Mises criterion for the cylinder and supporting rings, respectively. As predicted by the finite element analysis results, in the two-layer split dies with a round cylinder, the stress state of the cylinder can be only slightly improved; and the von Mises stress of the first layer supporting ring can be hardly decreased. However, in the two-layer split dies with a quadrate cylinder and sample cavity, the stress state of the cylinder can be remarkably improved. Simultaneously, the von Mises stress of the supporting rings, especially for the first-layer supporting ring, can be also effectively decreased. The pressure capacities of the two-layer split dies with a round cylinder and a quadrate cylinder are 16.5% and 63.9% higher with respect to the conventional belt-type die.

Analysis of Loads and Stresses for a Sewing Needle

2002 ◽  
Author(s):  
Yuan Mao Huang
Keyword(s):  
Shear Stress ◽  
Personal Computer ◽  
Failure Modes ◽  
Von Mises Stress ◽  
Bending Stress ◽  
Principal Stresses ◽  
Acceptable Accuracy ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Cost

This study analyzes the loads of a needle by using singularity functions and determines the Von-Mises stresses to predict the failure modes of needles by using a personal computer. After principal stresses are calculated from the bending stress, compressive stress and shear stress, predicted failure modes of needles based on the Von-Mises stress coincide with practical existing failure modes reported by a manufacturer. These calculated stresses are also compared with the results obtained by using the software ABAQUS in the mainframe, and the deviation between the results calculated by these two methods is also investigated. Using this methodology can obtain loads, stresses and failure modes of a needle with acceptable accuracy while reducing the cost of using the commercial software in the mainframe.

scholarly journals Effect of Fiber Posts on Stress Distribution of Endodontically Treated Upper Premolars: Finite Element Analysis

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1708 ◽  
Author(s):  
Maciej Zarow ◽  
Mirco Vadini ◽  
Agnieszka Chojnacka-Brozek ◽  
Katarzyna Szczeklik ◽  
Grzegorz Milewski ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Resin Composite ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Endodontically Treated Tooth ◽  
Maxillary Premolars ◽  
Von Mises

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin.

Elastic Analysis of Journal Bearings

Volume 1 ◽  
2004 ◽  
Author(s):  
M. M. Villar ◽  
M. M. Pe´rez
Keyword(s):  
Stress Distribution ◽  
General Purpose ◽  
Von Mises Stress ◽  
Elastic Analysis ◽  
Stress Distributions ◽  
Finite Element Program ◽  
Relative Significance ◽  
Element Program ◽  
Von Mises ◽  
Hoop Stresses

In this paper a numerical model is used to investigate the effect of the elasticity of the bearing in the pressure distribution in the lubricant and the stress distribution in the bearing. The lubricant film, as well as a bearing, including the lining and the backing of the insert, and the housing, are modeled using the general-purpose ANSYS®5.7 commercial Finite Element program. Results have been obtained for the pressure, radial displacement, hoop and von Mises stress distributions at the surface of the bearing, as well as for the shear stress distribution at the interface between the lining and the backing. A number of conclusions have been drawn regarding the relative significance of the steep pressure gradient at the end of the lubricated region on the hoop stresses that cause localized bending distortions at the surface of the lining. These localized bending distortions, in turn, are likely to cause fatigue failure of the lining.

Shear stress and von Mises stress distributions in the periphery of an embedded acetabular cup implant during impingement

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Christoph Arndt ◽  
Alexandra Görgner ◽  
Carsten Klöhn ◽  
Roger Scholz ◽  
Christian Voigt
Keyword(s):  
Shear Stress ◽  
Von Mises Stress ◽  
Shear Stresses ◽  
Periprosthetic Bone ◽  
Worst Case ◽  
Bone Interface ◽  
Numerical Predictions ◽  
Von Mises ◽  
Acetabular Implant ◽  
Interface Distance

AbstractAs literature implies, daily activities of total hip arthroplasty (THA) patients may include movements prone to implant-implant impingement. Thus, high shear stresses may be induced at the acetabular implant-bone interface, increasing the risk of implant loosening. The aim of the current study is to determine whether or not impingement events may pose an actual risk to acetabular periprosthetic bone. An existing experimental workflow was augmented to cover complete three-dimensional strain gage measurement. von Mises and shear stresses were calculated from 1620 measured strain values, collected around a hemispherical cup implant at 2.5 mm interface distance during worst-case impingement loading. A shear stress criterion for acetabular periprosthetic bone was derived from the literature. At the impingement site, magnitudes of von Mises stress amount to 0.57 MPa and tilting shear stress amount to -0.3 MPa at 2.5 mm interface distance. Conclusion can be drawn that worst-case impingement events are unlikely to pose a risk of bone material failure in the periphery around fully integrated cementless acetabular hip implants in otherwise healthy THA patients. As numerical predictions in the literature suggested, it can now be confirmed that impingement moments are unlikely to cause acetabular implant-bone interface fixation failures.

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.

Poisson Ratio Effects on the Von Mises and Maximum Shear Stresses in Cylindrical Contacts

2005 ◽  
Author(s):  
Itzhak Green
Keyword(s):  
Shear Stress ◽  
Poisson Ratio ◽  
Unit Length ◽  
Maximum Shear Stress ◽  
Critical Force ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Shear Stresses ◽  
Wide Range ◽  
Von Mises

This work determines the location of the greatest elastic distress in cylindrical contacts based upon the distortion energy and the maximum shear stress theories. The ratios between the maximum pressure, the von Mises stress, and the maximum shear stress are determined and fitted by empirical formulations for a wide range of Poisson ratios, which represent material compressibility. Some similarities exist between cylindrical and spherical contacts, where for many metallic materials the maximum von Mises or shear stresses emerge beneath the surface. However, if any of the bodies in contact is excessively compressible the maximum von Mises stress appears at the surface. That transitional Poisson ratio is found. The critical force per unit length that causes yielding onset, along with its corresponding interference and half-width contact are derived.

FE Analysis of the Effect of Material Gradient on the Performance of a Functionally Graded Endodontic Prefabricated Parallel Post

2015 ◽  
Vol 752-753 ◽  
pp. 382-386 ◽  
Author(s):  
Wasim M.K. Helal ◽  
Dong Yan Shi ◽  
Zhi Kai Wang
Keyword(s):  
Shear Stress ◽  
Volume Fraction ◽  
Fe Analysis ◽  
Functionally Graded ◽  
Von Mises Stress ◽  
Sigmoid Function ◽  
Current Investigation ◽  
Element Analysis ◽  
The Difference ◽  
Von Mises

A study of the effect of material gradient on the performance of a functionally graded endodontic prefabricated parallel post (FGEPPP) is the main goal of the current study. Elastic modulus (E) of FGEPPP is considered to vary continuously from lower to upper surfaces. This variation is performed according the volume fraction. Based on a modified sigmoid function, the volume fraction will be defined in the present work. The primary goal of the current investigation is to analyze the difference between the performance of a homogeneous endodontic prefabricated parallel post (EPPP) and a FGEPPP through finite element analysis (FEA). In the current investigation, von Mises stress, and shear stress in FGEPPP case with a modified sigmoid function and in homogeneous EPPP case are carried out. After that, the effect of material gradient on the performance of an EPPP made of FGM was carried out through FEA in the current investigation. The simulation cases shown that, the maximum values of von Mises stress, and shear stress increase when increasing the value of “D”, and decrease when increasing the value of “w”.

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