Influence of Mechanical Properties of Adhesives on Stress Distributions in Lap Joints

Volume 1 ◽  
2004 ◽  
Author(s):  
Xiaocong He ◽  
S. Olutunde Oyadiji
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Lap Joints ◽  
Stress Distributions ◽  
Element Analysis ◽  
Linear Elastic ◽  
Cantilevered Beam ◽  
Cantilevered Beams ◽  
Different Characteristics

This paper deals with stress analysis of a single lap-jointed cantilevered beam using the three dimensional linear elastic finite element analysis (FEA) technique. Numerical examples are provided to show the influence on the stresses of the single lap-jointed cantilevered beams using adhesives of different characteristics which encompass the entire spectrum of viscoelastic behaviour. The results indicate that the stress distributions of a single-lap jointed cantilevered beam are strongly affected by both Young’s modulus and Poisson’s ratios. The maximum stress ratio was used to determine maximum values of Young’s Modulus required in order that the static stresses of an adhesively bonded cantilevered beam will not be more than given value of that of the equivalent homogeneous structure, that is a geometrically similar beam but without a joint. The analysis results also show that by choosing suitable adhesives, the maximum stresses can be reduced and the strength can be improved.

Three-dimensional deformations in a single-lap joint

1994 ◽  
Vol 29 (2) ◽  
pp. 137-145 ◽  
Author(s):  
M Y Tsai ◽  
J Morton
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Lap Joint ◽  
Displacement Fields ◽  
Element Analysis ◽  
Linear Elastic ◽  
Non Linear ◽  
Linear Effects ◽  
Peel Stress

The three-dimensional nature of the state of deformation in a single-lap test specimen is investigated in a linear elastic finite element analysis in which the boundary conditions account for the geometrically non-linear effects. The validity of the model is demonstrated by comparing the resulting displacement fields with those obtained from a moiré inteferometry experiment. The three-dimensional adherend and adhesive stress distributions are calculated and compared with those from a two-dimensional non-linear numerical analysis, Goland and Reissner's solution, and experimental measurements. The nature of the three-dimensional mechanics is described and discussed in detail. It is shown that three-dimensional regions exists in the specimen, where the adherend and adhesive stress distributions in the overlap near (and especially on) the free surface are quite different from those occurring in the interior. It is also shown that the adhesive peel stress is extremely sensitive to this three-dimensional effect, but the adhesive shear is not. It is also observed that the maximum value of the peel stress occurs at the end of the overlap in the central two-dimensional core region, rather than at the corners where the three-dimensional effects are found. The extent of three-dimensional regions is also quantified.

A Stress Analysis and Strength Estimation of Stepped Lap Adhesive Joints Under Static and Impact Tensile Loadings

2005 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Kohei Ichikawa
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Adhesive Joints ◽  
Stress Distributions ◽  
Maximum Value ◽  
Dimensional Finite Element ◽  
Static Tensile ◽  
Three Dimensional Finite Element ◽  
The Impact

The stress variations and stress distributions in stepped-lap adhesive joints of dissimilar adherends under impact tensile loadings were analyzed in elastic range using three-dimensional finite element method. The impact loadings were applied to the lower adherend by dropping a weight. The stress distributions in stepped-lap adhesive joints of dissimilar adherends under static tensile loadings were also analyzed using FEM. The effects of Young’s modulus of the adherends, the adhesive thickness and the number of butted steps of adherents ware examined under both impact and static loadings. As the results, The maximum value of stress σ1 increased as Young’s modulus of the adherends increased for the impact loadings. The maximum value of stress σ1 increased as the numbers of steps in the adherends increased for the static loadings. In addition, the experiments to measure the strain response of joints subjected to impact tensile loadings were carried out using strain gauges. A fairly good agreement was found between the numerical and the measured results concerning the strain responses.

3-D FEM Stress Analysis and Strength of Adhesive-Rivets Combination Joints Under Static and Impact In-Plane Bending Moments

2008 ◽  
Author(s):  
Ryo Nogaito ◽  
Toshiyuki Sawa ◽  
Atsushi Karami
Keyword(s):  
Young’S Modulus ◽  
Impact Load ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Axial Direction ◽  
Bending Moments ◽  
Stress Distributions ◽  
Plane Bending ◽  
Peel Stress ◽  
The Impact

Stress distributions in adhesive-rivets combination joints subjected static bending moments are calculated using three-dimensional finite-element calculations. The stress propagation and stress distribution subjected to impact bending moments are also calculated using three-dimensional FEM calculations. In the FEM calculations, the effects of number, position and diameter of rivets, and Young’s modulus of the rivet on the stress distributions at the adhesive interface are examined from fail-safe design standpoints. From the FEM results, the maximum value of peel stress decreases as the position of rivets in the axial direction is decreased and the position of rivets in the width direction increases in the joints with two and four rivets. It is also found that the results on the stress distributions in the joints under the static bending moments show the same tendency of the joints under the impact in-plane bending moments. Concerning the effect of Young’s modulus of the rivet, it is not seen on the peel stress under the static in-plane bending moments. For the verification of the FEM calculations, the experiments were carried out to measure the strain response under both static and impact load conditions. Fairly good agreements are observed between the FEM calculations and the measured results.

A Stress Analysis of Stepped Lap and Scarf Adhesive Joints Under Static Tensile Loadings

2005 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Masahiro Sasaki
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Adhesive Joints ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Static Tensile ◽  
Three Dimensional Finite Element ◽  
Stress Variations ◽  
The Impact

The stress variations and stress distributions in scarf and stepped-lap adhesive joints of similar adherends under static and impact tensile loadings were analyzed in elastic range using three-dimensional finite element method. The impact loadings were applied to the lower adherend by dropping a weight. The stress distributions in scarf adhesive joints of similar adherends under static tensile loadings were also analyzed using FEM. The effects of Young’s modulus of the adherends, the adhesive thickness, and the angle of the adherends on the stress distributions at the interfaces between the adherends and the adhesive were examined under static loadings. The maximum value of σ1 decreased as young’s modulus of the adhesive increased in the stepped-lap adhesive joints under static loadings. However, the result of the scarf adhesive joints under static loadings was opposite to the above result. The value of σ1 became minimum when the scarf angle was 52°in the scarf adhesive joint. In addition, the experiments to measure the strain response and strain of joints subjected to impact and static tensile loadings were carried out using strain gauges. Fairly good agreements ware found between the numerical and the measured results.

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.

FEM Stress Analysis and Strength of Scarf Adhesive Joints of Similar Adherend Subjected to Impact Tensile Loadings

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Hirayama ◽  
He Dan
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Stress Wave ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Adhesive Thickness ◽  
Three Dimensional Finite Element

The stress wave propagation and stress distribution in scarf adhesive joints have been analyzed using three-dimensional finite element method (FEM). The FEM code employed was LS-DYNA. An impact tensile loading was applied to the joint by dropping a weight. The effect of the scarf angle, Young’s modulus of the adhesive and adhesive thickness on the stress wave propagations and stress distributions at the interfaces have been examined. As the results, it was found that the point where the maximum principal stress becomes maximum changes between 52 degree and 60 degree under impact tensile loadings. The maximum value of the maximum principal stress increases as scarf angle decreases, Young’s modulus of the adhesive increases and adhesive thickness increases. In addition, Experiments to measure the strains and joint strengths were compared with the calculated results. The calculated results were in fairly good agreements with the experimental results.

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.

Influence of Interference and Clamping on Fretting Fatigue in Single Rivet-Row Lap Joints

2000 ◽  
Vol 123 (4) ◽  
pp. 686-698 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Crack Initiation ◽  
Three Dimensional ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Lap Joints ◽  
Element Analysis ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Fretting Damage

Primary fretting fatigue variables such as contact pressure, slip amplitude and bulk cyclic stresses, at and near the contact interface between the rivet shank and panel hole in a single rivet-row, 7075-T6 aluminum alloy lap joint are presented. Three-dimensional finite element analysis is applied to evaluate these and the effects of interference and clamping stresses on the values of the primary variables and other overall measures of fretting damage. Two rivet geometries, non-countersunk and countersunk, are considered. Comparison with previous evaluations of the fretting conditions in similar but two-dimensional connections indicates that out-of-plane movements and attending effects can have a significant impact on the fatigue life of riveted connections. Variations of the cyclic stress range and other proponents of crack initiation are found to peak at distinct locations along the hole-shank interface, making it possible to predict crack initiation locations and design for extended life.

scholarly journals Organizing Cells Within Non-Periodic Microarchitectured Materials That Achieve Graded Thermal Expansions

2015 ◽  
Author(s):  
Jonathan B. Hopkins ◽  
Lucas A. Shaw ◽  
Todd H. Weisgraber ◽  
George R. Farquar ◽  
Christopher D. Harvey ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Element Analysis ◽  
Thermal Expansion Coefficients ◽  
Large Lattice ◽  
Unit Cells ◽  
Expansion Coefficients ◽  
Bulk Behavior

The aim of this paper is to introduce an approach for optimally organizing a variety of different unit cell designs within a large lattice such that the bulk behavior of the lattice exhibits a desired Young’s modulus with a graded change in thermal expansion over its geometry. This lattice, called a graded microarchitectured material, can be sandwiched between two other materials with different thermal expansion coefficients to accommodate their different expansions or contractions caused by changing temperature while achieving a desired uniform stiffness. First, this paper provides the theory necessary to calculate the thermal expansion and Young’s modulus of large multi-material lattices that consist of periodic (i.e., repeating) unit cells of the same design. Then it introduces the theory for calculating the graded thermal expansions of a large multimaterial lattice that consists of non-periodic unit cells of different designs. An approach is then provided for optimally designing and organizing different unit cells within a lattice such that both of its ends achieve the same thermal expansion as the two materials between which the lattice is sandwiched. A MATLAB tool is used to generate images of the undeformed and deformed lattices to verify their behavior and various examples are provided as case studies. The theory provided is also verified and validated using finite element analysis and experimentation.

The Site Tilt and Lander Transfer Function from the Short-Period Seismometer of InSight on Mars

2021 ◽  
Author(s):  
Alexander E. Stott ◽  
Constantinos Charalambous ◽  
Tristram J. Warren ◽  
William T. Pike ◽  
Robert Myhill ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Dust Devils ◽  
Total Change ◽  
Noise Sources ◽  
Element Analysis ◽  
Near Surface ◽  
Seismic Experiment ◽  
Short Period ◽  
Sensitivity Changes

ABSTRACT The National Aeronautics and Space Administration InSight mission has deployed the seismic experiment, SEIS, on the surface of Mars, and has recorded a variety of signals including marsquakes and dust devils. This work presents results on the tilt and local noise sources, which provide context to aid interpretation of the observed signals and allow an examination of the near-surface properties. Our analysis uses data recorded by the short-period sensors on the deck, throughout deployment and in the final configuration. We use thermal decorrelation to provide an estimate of the sol-to-sol tilt. This tilt is examined across deployment and over a Martian year. After each modification to the site, the tilt is seen to stabilize over 3–20 sols depending on the action, and the total change in tilt is <0.035°. Long-term tilt over a Martian year is limited to <0.007°. We also investigate the attenuation of lander-induced vibrations between the lander and SEIS. Robotic arm motions provide a known lander source in the 5–9 Hz bandwidth, yielding an amplitude attenuation of lander signals between 100 and 1000 times. The attenuation of wind sensitivity from the deck to ground presents a similar value in the 1.5–9 Hz range, thus favoring a noise dominated by lander vibrations induced by the wind. Wind sensitivities outside this bandwidth exhibit different sensitivity changes, indicating a change in the coupling. The results are interpreted through a finite-element analysis of the regolith with a depth-dependent Young’s modulus. We argue that discrepancies between this model and the observations are due to local compaction beneath the lander legs and/or anelasticity. An estimate for the effective Young’s modulus is obtained as 62–81 MPa, corroborating previous estimates for the top layer duricrust.

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