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.

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 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.

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.

Testing of In-Plane Shear Properties under Fatigue Loading

1995 ◽  
Vol 14 (9) ◽  
pp. 965-987 ◽  
Author(s):  
Larry B. Lessard ◽  
Olivia P. Eilers ◽  
Mahmood M. Shokrieh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
High Stress ◽  
Fatigue Loading ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Plane Shear ◽  
Shear Properties ◽  
Notched Specimens

A two-dimensional finite element analysis is performed in order to analyze and improve the performance of the three-rail shear test specimen as prescribed by the ASTM Standard Guide for testing of in-plane shear properties of composite laminates [1]. Of main interest is the location of high-magnitude stresses in the matrix direction that affect the fatigue life of the specimen. Through finite element analysis, the optimal specimen configuration is determined by inserting slots in the positions at which there are stress concentrations. This has the effect of transferring the location of high stress away from critical areas, thus increasing the fatigue life of the specimen. The results are verified by three-rail shear tests performed for both standard un-notched and new notched specimens. The notched specimens show great improvement in both static strength and fatigue life.

Dynamic Crush Behavior of Aluminum 5052-H38 Honeycomb Specimens Under Out-of-Plane Inclined Loads

2004 ◽  
Author(s):  
Sung-tae Hong ◽  
Jwo Pan ◽  
Tau Tyan ◽  
Priya Prasad
Keyword(s):  
Impact Velocity ◽  
Stress Distributions ◽  
Element Analysis ◽  
Test Fixture ◽  
Linear Elastic ◽  
Inclined Loads ◽  
Out Of Plane ◽  
The Impact ◽  
Crush Strength ◽  
Stress Free Boundary

The dynamic crush behavior of aluminum 5052-H38 honeycomb specimens under out-of-plane inclined loads is investigated. Honeycomb specimens were designed to minimize the secondary stresses under out-of-plane inclined loads. A test fixture was designed such that inclined loads can be applied in dynamic crush tests. A static linear elastic finite element analysis was performed to understand the stress distributions in honeycomb specimens under inclined loads. The computational results show that the secondary stresses of the specimens are limited to the region near the stress-free boundary. The results of dynamic crush tests indicate that the effects of the impact velocity on the crush strengths are significant. Under dynamic loads, as the impact velocity increases, the crush strengths increase. The trends of the inclined crush strengths for specimens with different in-plane orientation angles as functions of the impact velocity are very similar to that of the pure compressive crush strength. Honeycomb specimens under pure compressive and inclined loads show similar progressive folding mechanisms. The similar trends of the crush strengths as functions of the impact velocity are possibly due to the similar progressive folding mechanisms.

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.

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.

Effective Convergence Checks for Verifying Finite Element Stresses at Three-Dimensional Stress Concentrations

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair ◽  
P. J. Roache
Keyword(s):  
Finite Element ◽  
Error Estimation ◽  
A Posteriori Error Estimates ◽  
Three Dimensional ◽  
Posteriori Error ◽  
Test Problems ◽  
A Posteriori ◽  
Stress Concentrations ◽  
Element Analysis ◽  
A Posteriori Error

Current computational capabilities facilitate the application of finite element analysis (FEA) to three-dimensional geometries to determine peak stresses. The three-dimensional stress concentrations so quantified are useful in practice provided the discretization error attending their determination with finite elements has been sufficiently controlled. Here, we provide some convergence checks and companion a posteriori error estimates that can be used to verify such three-dimensional FEA, and thus enable engineers to control discretization errors. These checks are designed to promote conservative error estimation. They are applied to twelve three-dimensional test problems that have exact solutions for their peak stresses. Error levels in the FEA of these peak stresses are classified in accordance with: 1–5%, satisfactory; 1/5–1%, good; and <1/5%, excellent. The present convergence checks result in 111 error assessments for the test problems. For these 111, errors are assessed as being at the same level as true exact errors on 99 occasions, one level worse for the other 12. Hence, stress error estimation that is largely reasonably accurate (89%), and otherwise modestly conservative (11%).

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

scholarly journals Evaluation of Different Restoration Combinations Used in the Reattachment of Fractured Teeth: A Finite Element Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Nagihan Guven ◽  
Ozgur Topuz ◽  
İhsan Yikilgan
Keyword(s):  
Finite Element Analysis ◽  
Glass Fiber ◽  
Composite Resin ◽  
Fracture Line ◽  
Core Material ◽  
Fiber Post ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Composite Resin Restoration ◽  
Glass Fiber Post

Objective. The purpose of this study was to test different restoration combinations used for constructing fractured endodontically treated incisors by reattaching their fractured fragments. Methods. Seven types of 3-D FEM mathematical root canal-filled models were generated, simulating cases of (OB) reattaching fractured fragments; (CrPL) reattaching fractured fragments + ceramic palatinal laminate; (CmPL) reattaching fractured fragments + composite palatinal laminate; (CM) reattaching fractured fragments + coronal 1/3 of the root was filled using core material; (BP) reattaching fractured fragments + glass fiber post; (CP) composite resin restoration + glass fiber post; and (OC) composite resin restoration. A 100-N static oblique force was applied to the simulated teeth with 135° on the node at 2 mm above the cingulum to analyze the stress distribution at the tooth. Results. For enamel tissue, the highest stress values were observed in model BP, and the lowest stress values were observed in model CmPL. For dentine tissue, the highest stress concentrations were observed around the fracture line for all models. Conclusions. Reattachment of fractured fragments by bonding may be preferred as a restoration option for endodontically treated incisors; also, palatinal laminate decreases the stress values at tooth tissues, especially at the enamel and the fracture line.

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