Detailed stress analysis of a twill orthogonally woven textile composite

2020 ◽  
Vol 54 (25) ◽  
pp. 3801-3820
Author(s):  
M Keith Ballard ◽  
John D Whitcomb
Keyword(s):  
Stress State ◽  
High Performance ◽  
Small Region ◽  
Stress Distributions ◽  
Severe Stress ◽  
Stress Concentrations ◽  
Textile Composite ◽  
Element Analysis ◽  
Sharp Edges ◽  
Woven Textile

A finite element analysis framework that leverages high-performance computing was used to analyze a twill orthogonally woven textile model. Boundary conditions for uniaxial tension along the warp direction were applied to a large analysis region, and an interior subregion was used for investigating the stress distributions. The locations of severe stresses were investigated for the binders, wefts, warps, and matrix, respectively, and the connection of the stress state to the surrounding tow architecture was discussed. It was shown that the highest stresses developed in the binders where the path of a binder changed direction, due to a transfer of load to nearby wefts that induced a severe shear stress in the binder. Additionally, severe stress concentrations were observed in both the wefts and binders where the binders traversed the thickness of the textile and came near a weft. The magnitude of the concentration in the binders closely matched across similar locations. On the other hand, the concentrations in the weft appeared to be sensitive to the faceted surfaces of the tows, which sometimes resulted in sharp edges, but these stress the concentrations in the wefts did remain localized. In the warps, the normal stress in the direction of the load was the largest, but the most severe stress state was shown to occur in a very small region where warps came close to binders as the path of the binder transitioned.

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.

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.

Study of a Specimen with Stress Concentrators in Multiaxial Tests

2015 ◽  
Vol 809-810 ◽  
pp. 974-979 ◽  
Author(s):  
Ana Maria Comanici ◽  
Viorel Goanta ◽  
Paul Doru Barsanescu ◽  
Liviu Andrusca
Keyword(s):  
Experimental Investigation ◽  
Stress State ◽  
Accurate Information ◽  
Stress Concentrations ◽  
State Distribution ◽  
Element Analysis ◽  
Investigation Methods ◽  
Methods And Techniques ◽  
Limit Stress ◽  
Distribution Of Stresses

Experimental investigation methods and techniques are used to obtain accurate information on the tension and deformation of materials. Results underlying the limit stress state that aply to materials at this moment come from experiments on plain specimens and specimens showing stress concentrations. The study of stress concentrations is necessary to determine how it influences the limit stress state, distribution of stresses and yielding section. The article presents a series of specimens with stress concentrations and finite element analysis for thorough research.

Stress analysis of axisymmetric butt joints loaded in torsion and tension

1978 ◽  
Vol 13 (1) ◽  
pp. 1-10 ◽  
Author(s):  
R D Adams ◽  
J Coppendale ◽  
N A Peppiatt
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Adhesive Properties ◽  
Butt Joints ◽  
Element Analysis ◽  
Tensile Stresses

Axisymmetric butt joints are widely used as specimens for testing the response of adhesives to shear and tensile stresses. When analysing the results from these tests, the stress distributions must be accurately known. A finite-element analysis has been used to examine the effect of non-rigid adherends and a spew fillet in solid and annular butt joints for a range of geometries and adhesive properties. It has been shown that stress concentrations occur in butt joints loaded in tension; in the latter case, the stress concentration is directly due to the presence of the spew fillet.

Stress Distribution Properties in Adhesively Bonded Beams

2014 ◽  
Vol 556-562 ◽  
pp. 720-724 ◽  
Author(s):  
Xiao Cong He ◽  
Yu Qi Wang ◽  
Hua Ying Cun ◽  
Sheng Wan Yuan
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Small Region ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Dimensional Finite Element ◽  
Centre Region ◽  
Three Dimensional Finite Element

The stress distribution properties in a single lap-jointed cantilevered adhesive beam have been investigated using three dimensional finite element methods. Finite element solutions of the stress distributions in the adhesive layer have been obtained for three typical boundary conditions. It was found that the stress concentrations are confined to a very small region near the free ends of interfaces between the adherend and the adhesive layer while the centre region of the adhesive layer is mostly stress-free. This suggests that the first failure may be expected at the free ends of interfaces between the adherend and the adhesive layer. This also implies that the adhesive material near the free ends of the adhesive layer is mainly bearing the load being transferred through the adhesive joint. The analysis results show that by choosing suitable boundary condition, the bending effect can be reduced and the strength, fatigue life and reliability of the bond can be improved.

Stress analysis of a plain orthogonally woven textile composite under tension along the warp direction

2019 ◽  
Vol 53 (20) ◽  
pp. 2809-2829
Author(s):  
M Keith Ballard ◽  
John D Whitcomb
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Normal Stress ◽  
Local Coordinate System ◽  
Mesh Refinement ◽  
Element Model ◽  
Stress Concentrations ◽  
Textile Composite ◽  
Volume Average ◽  
Woven Textile

A non-idealized finite element model of a plain orthogonally woven textile composite was subjected to tension along the warp direction, and the predicted stress state was investigated. The effect of refining the geometry and mesh on the volume average stresses and the percentage of each constituent at different stress levels was explored. For the particular textile architecture considered, which consisted of large reinforcement tows and complex tow cross sections, it was shown that the typical mesh refinement in the literature might suffice for volume average stresses, but a higher mesh refinement is needed to accurately capture stress concentrations. The locations of stress concentrations within each constituent were identified. For the three types of tows, [Formula: see text], transverse normal stress in the local coordinate system, in the wefts was predicted to be the most severe component of stress. For the layers of wefts that are crossed over or under by a binder, stress concentrations developed where the warps were the most distorted. Whereas, for the interior layer of wefts, stress concentrations developed where a binder came closest to the weft. In the matrix, [Formula: see text], the normal stress in the direction of the load, concentrations developed where a binder came close to a warp or weft. The locations of peak cross-sectionally averaged stresses along the tow paths were shown to match the locations of local stress concentrations. However, it was observed that many of the stress concentrations might be sensitive to the method used to create the finite element model, boundary conditions, or accounting for the variation of local fiber-volume fraction that results from a variation of cross-sectional area.

An integrated method for off-axis tension and compression testing of unidirectional composites

2010 ◽  
Vol 45 (6) ◽  
pp. 657-669 ◽  
Author(s):  
Y. Xiao ◽  
M. Kawai ◽  
H. Hatta
Keyword(s):  
Compression Testing ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Plane Shear ◽  
Unidirectional Composites ◽  
Test Fixture ◽  
Integrated Method ◽  
Tension And Compression ◽  
Grip Test

This study presents an integrated method suitable for off-axis tension and compression testing in unidirectional composites, and its application to the testing of in-plane shear characterization. A new rotating-grip test fixture, incorporating the attractive features of the existing pinned-end fixture and hydraulic wedge grips, has been developed. The proposed gripping system consists of two sets of jaw faces, each with a pair of self-aligning bearings that allows for loading in the axial and radial directions. Finite element analysis and experiments were performed to evaluate the effectiveness of the rotating-grip test fixture. Results from numerical calculations show that this method reduces stress concentrations near the end and produces relatively uniform stress distributions in the specimen gage section. Mechanical testing results show a considerable increase in the measured shear properties of composites, compared with the existing end grip systems. The results indicated that the new test fixture is significantly better than the conventional fixture, and is also comparable to the method of the oblique end-tab for off-axis testing.

Parallel Computing for Tire Simulations

2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar
Keyword(s):  
High Performance ◽  
Effective Means ◽  
Cost Effective ◽  
Turnaround Time ◽  
Careful Consideration ◽  
Rolling Contact ◽  
Element Analysis ◽  
Parallel Solvers ◽  
Design Changes ◽  
Highly Nonlinear

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

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