Deformation in Multilayer Stacked Assemblies

1990 ◽  
Vol 112 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Tsung-Yu Pan ◽  
Yi-Hsin Pao
Keyword(s):  
Thermal Loading ◽  
Bending Moment ◽  
Radius Of Curvature ◽  
Element Analysis ◽  
First Order ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Nonlinear Stress ◽  
Order Polynomial ◽  
Vertical Displacements

A linear-elastic analytical model has been developed to describe the deformed geometry of a multi-layered stack assembly subject to thermal loading. The model is based on Timoshenko’s bimetal thermostat analysis [1] and consists of a series of first-order polynomial equations. The radius of curvature, bending moment, force, horizontal and vertical displacements can be determined numerically. These quantities match well with finite element analysis. Calculations for silicon power transistor stacks are presented in order to demonstrate the model capability. The results from this analyitcal model have been found to correlate well with experimental measurements when an appropriate secant modulus is used to represent the nonlinear stress-strain behavior of solder.

Cord/Rubber Material Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 830-856 ◽  
Author(s):  
R. J. Cembrola ◽  
T. J. Dudek
Keyword(s):  
Finite Element ◽  
Material Model ◽  
Rubber Composites ◽  
Stress Strain ◽  
Element Analysis ◽  
Rubber Layer ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Interlaminar Shear ◽  
Mechanics Of Composite Materials

Abstract Recent developments in nonlinear finite element methods (FEM) and mechanics of composite materials have made it possible to handle complex tire mechanics problems involving large deformations and moderate strains. The development of an accurate material model for cord/rubber composites is a necessary requirement for the application of these powerful finite element programs to practical problems but involves numerous complexities. Difficulties associated with the application of classical lamination theory to cord/rubber composites were reviewed. The complexity of the material characterization of cord/rubber composites by experimental means was also discussed. This complexity arises from the highly anisotropic properties of twisted cords and the nonlinear stress—strain behavior of the laminates. Micromechanics theories, which have been successfully applied to hard composites (i.e., graphite—epoxy) have been shown to be inadequate in predicting some of the properties of the calendered fabric ply material from the properties of the cord and rubber. Finite element models which include an interply rubber layer to account for the interlaminar shear have been shown to give a better representation of cord/rubber laminate behavior in tension and bending. The application of finite element analysis to more refined models of complex structures like tires, however, requires the development of a more realistic material model which would account for the nonlinear stress—strain properties of cord/rubber composites.

ANALYSIS OF AN INTERNAL FIXATION OF A LONG BONE FRACTURE

2005 ◽  
Vol 05 (01) ◽  
pp. 89-103 ◽  
Author(s):  
K. RAMAKRISHNA ◽  
I. SRIDHAR ◽  
S. SIVASHANKER ◽  
V. K. GANESH ◽  
D. N. GHISTA
Keyword(s):  
Stress Shielding ◽  
Axial Loading ◽  
Bending Moment ◽  
Fracture Site ◽  
Long Bone ◽  
Radius Of Curvature ◽  
Element Analysis ◽  
Long Bone Fracture ◽  
Fracture Interface ◽  
Tensile Surface

A major concern when a fractured bone is fastened by stiff-plates to the bone on its tensile surface is excessive stress shielding of the bone. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays bone healing. Likewise, the tensile stress shielding of the healed bone underneath the plate also does not enable it to recover its tensile strength. Initially, the effect of a uniaxial load and a bending moment on the assembly of bone and plate is investigated analytically. The calculations showed that the screws near the fracture site transfers more load than the screws away from the fracture site in axial loading and it is found that less force is required when the screw is placed near to fracture site than the screw placed away from the fracture site to make the bone and plate bend with same radius of curvature when subjected to bending moment. Finally, the viability of using a stiffness graded bone-plate as a fixator is studied using finite element analysis (FEA): the stiffness-graded plate cause less stress-shielding than stainless steel plate.

Buckling of Ring Stiffened Pontoons of Floating Roofs in Aboveground Oil Storage Tanks

2007 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuhiro Kitamura
Keyword(s):  
Large Diameter ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Element Analysis ◽  
Linear Elastic ◽  
Structural Problems ◽  
Oil Storage ◽  
Bifurcation Buckling ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Six single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery in Tomakomai, Japan. The pontoon of floating roof might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which might be caused in the lap-welded joints or in the stress concentrated parts of the pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The failure of the roof expanded gradually in the sinking process. It is presumed that the initial small failures were caused by the elastic buckling of the pontoon due to circumferential bending moment. In this paper, the buckling strength of the pontoon is presented using axisymmetric shell finite element analysis. Linear elastic bifurcation buckling analyses are carried out and the buckling characteristics of ring stiffened pontoons are investigated.

A Study on the Behavior Characteristics of Curved FRP-Concrete Composite Panel

2012 ◽  
Vol 557-559 ◽  
pp. 375-380 ◽  
Author(s):  
Woo Tai Jung ◽  
Jong Sup Park ◽  
Seung Han Kim
Keyword(s):  
Construction Material ◽  
Maximum Load ◽  
Composite Panel ◽  
Elastic Behavior ◽  
Radius Of Curvature ◽  
Element Analysis ◽  
Linear Elastic ◽  
Reinforced Polymer ◽  
Loading Tests ◽  
Behavior Characteristics

Following the recent growing interest on long-lasting structures, various researches attempt to exploit Fiber Reinforced Polymer (FRP) to constructions owing to the remarkable reduction of maintenance costs brought by its outstanding resistance to corrosion. However, research dedicated to curved FRP construction material applicable to tunnel or arch bridge is still absent. This study conducts loading tests and finite element analysis in order to examine the behavior of curved FRP-concrete panel produced by pultrusion. The test results reveal that FRP and concrete exhibit linear elastic behavior until the maximum load. The parametric analysis with various FRP sections shows that the behavior of the curved FRP-concrete composite panel depends on the web height of FRP, the spacing of the webs, the length of the flange and the radius of curvature.

scholarly journals Biomechanical characterization of the periodontal ligament: Orthodontic tooth movement

2016 ◽  
Vol 87 (2) ◽  
pp. 183-192 ◽  
Author(s):  
Richard Uhlir ◽  
Virginia Mayo ◽  
Pei Hua Lin ◽  
Si Chen ◽  
Yan-Ting Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Anatomical Location ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Force Vectors

ABSTRACT Objective: To quantify the biomechanical properties of the bovine periodontal ligament (PDL) in postmortem sections and to apply these properties to study orthodontic tooth intrusion using finite element analysis (FEA). We hypothesized that PDL's property inherited heterogeneous (anatomical dependency) and nonlinear stress-strain behavior that could aid FEA to delineate force vectors with various rectangular archwires. Materials and Methods: A dynamic mechanical analyzer was used to quantify the stress-strain behavior of bovine PDL. Uniaxial tension tests using three force levels (0.5, 1, and 3 N) and samples from two anatomical locations (circumferential and longitudinal) were performed to calculate modulus. The Mooney-Rivlin hyperelastic (MRH) model was applied to the experimental data and used in an FEA of orthodontic intrusion rebounded via a 0.45-mm step bend with three archwire configurations of two materials (stainless steel and TMA). Results: Force levels and anatomical location were statistically significant in their effects on modulus (P < .05). The apical part had a greater stiffness than did the middle part. The MRH model was found to approximate the experimental data well (r = 0.99), and it demonstrated a reasonable stress-strain outcome within the PDL and bone for FEA intrusion simulation. The force acting on the tooth increased five times from the 0.016 × 0.022-inch TMA to the 0.019 × 0.025-inch stainless steel. Conclusions: The PDL is a nonhomogeneous tissue in which the modulus changed in relation to location. PDL nonlinear constitutive model estimated quantitative force vectors for the first time to compare intrusive tooth movement in 3-D space in response to various rectangular archwires.

scholarly journals Numerical Study on Plastic Strain Distributions and Mechanical Behaviour of a Tube under Bending

Inventions ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 9
Author(s):  
Chiemela Victor Amaechi ◽  
Emmanuel Folarin Adefuye ◽  
Abiodun Kolawole Oyetunji ◽  
Idris Ahmed Ja’e ◽  
Ibitoye Adelusi ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Mechanical Behaviour ◽  
Numerical Study ◽  
Bending Moment ◽  
Thickness Effect ◽  
Element Analysis ◽  
Cross Sectional ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Pipe Bending

Tubular pipe structures have been used in various applications—domestic, aviation, marine, manufacturing and material testing. The applications of tubular pipes have been considered greatly in the installation of tubular pipes, marine risers and pipe bending. For the investigation of plastic strains and the mechanical behaviour of a tube under bending, considerations were made utilising an exponent model with assumptions on the plane strain. The bending moment, wall thickness effect, cross-sectional distribution, stresses during bending and neutral layer boundaries were all presented as necessary theoretical formulations on the physics of tubular pipe bending. This model was based on the analytical and numerical investigation. In principle, the application can be observed as the spooling of pipes, bending of pipes and reeling. Comparisons were made on two models developed on the finite element analysis in Simscale OpenFEA, namely the linear-elastic and the elasto-plastic models. This study presents visualization profiles using plastic strain to assess its effect on the tubular pipes. This can increase due to the limitation of plastic deformation on the composite materials selected.

Residual Stress Analysis of Bimaterial Strips Under Multiple Thermal Loading

1997 ◽  
Vol 119 (4) ◽  
pp. 281-287 ◽  
Author(s):  
J. W. Tierney ◽  
J. W. Eischen
Keyword(s):  
Residual Stress ◽  
Power Law ◽  
Thermal Loading ◽  
Material Behavior ◽  
Algebraic Equations ◽  
Stress Strain ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Nonlinear Stress ◽  
Microelectronics Industry

The residual stress distribution in bimaterial beams induced by multiple thermal loadings has been investigated. Three models for the nonlinear stress-strain material behavior were considered: bilinear elastic-plastic, power law elastic-plastic, and power law purely plastic. The equations governing equilibrium, compatibility of strain, and stress-strain for the bimaterial configuration make up a system of nonlinear algebraic equations which is solved numerically. The elastic-plastic power law model leads to stress discontinuity in the layers. The other two models have been verified with a finite element analysis. Several examples are included using materials common to the microelectronics industry.

scholarly journals Behavior of concrete beams reinforced with FRP during bending

2021 ◽  
Vol 263 ◽  
pp. 02052
Author(s):  
Igor Gorbunov ◽  
Vladimir Kakusha
Keyword(s):  
Crack Formation ◽  
Concrete Beams ◽  
Bending Moment ◽  
Bending Stiffness ◽  
Fiber Reinforced Polymer ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Reinforced Polymer ◽  
Glass Frp ◽  
Frp Bars

Article describes methods and results of experimental research for strain behavior, crack formation and fracture of concrete beams reinforced with fiber reinforced polymer (FRP) bars during bending moment action. 18 beams (3+3 series) reinforced with glass FRP (GFRP) and basalt (BFRP) 6, 10 and 14 mm in diameter were tested. Deflection in the middle of the beam, concrete and bars strain and ultrasonic transmission time for 4 routes were measured during tests besides visual inspection. Main crack formation occurred at 8-20% of the ultimate load for all beams. Crack formation was transition border to linear (elastic) straining at low bending stiffness. More than 15 times decrease in bending stiffness was seen for beam reinforced with two types of bars 6 mm in diameter compared to initial values. Existence of main cracks and major deflections is not allowed during design of bending elements. However small bending stiffness at linear elastic straining is a positive factor in case of «hard» loading and impact (pulsed) loading. It is possible to prevent structures collapse and people deaths at impact loading and cyclic «hard» loading by permitting crack formation in load bearing structures.

Analysis of Nonlinear Stress—Strain Relationship of Large Elastic Deformation of Rubber and Studies on Rubber—Rubber Composites

1991 ◽  
Vol 64 (5) ◽  
pp. 696-707 ◽  
Author(s):  
Amalendu Sarkar ◽  
Debashis Dutta ◽  
Anil K. Bhowmick ◽  
Swapan Majumdar
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Crack Tip ◽  
Deformation Pattern ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Strain Relationship ◽  
Type Composite

Abstract 1. A computer program based on the numerical method of finite-element analysis using Rivlin-Saunder's equation has been developed for the calculation of nonlinear stress-strain behavior of rubber. 2. The experimental stress-strain relationship can be predicted from the above theory. 3. The theoretical deformation pattern of a binary joint composite is in qualitative agreement with the experimental findings. 4. The stress-distribution pattern of the binary joints is largely dependent upon the geometry of the composite. The stress distribution of the transverse-type composite follows a linear relationship, while for the radial type composite, it increases gradually and reaches a maximum value at the bondline junction, then it again decreases with further increments in value of the y-axis. 5. The more acute the joint angle is, the higher is the stress concentration at the angle tip. 6. The higher the difference in the modulus value across the interface, the higher is the shear stress at the junction and the lower the tensile strength. 7. For transverse type composites, the stress concentration at the crack tip near to the edge is much higher than that at the crack tip near the bondline. 8. In the case of adhesively bonded joints, the stresses along the bondline decrease with the increase in distance away from the crack front.

scholarly journals A Multiscale Approach to Modeling the Passive Mechanical Contribution of Cells in Tissues

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Victor K. Lai ◽  
Mohammad F. Hadi ◽  
Robert T. Tranquillo ◽  
Victor H. Barocas
Keyword(s):  
Volume Fraction ◽  
Multiscale Model ◽  
Biological Tissues ◽  
Multiscale Approach ◽  
Fiber Network ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Spherical Inclusions ◽  
Nonlinear Stress ◽  
Filament Network

In addition to their obvious biological roles in tissue function, cells often play a significant mechanical role through a combination of passive and active behaviors. This study focused on the passive mechanical contribution of cells in tissues by improving our multiscale model via the addition of cells, which were treated as dilute spherical inclusions. The first set of simulations considered a rigid cell, with the surrounding ECM modeled as (1) linear elastic, (2) Neo-Hookean, and (3) a fiber network. Comparison with the classical composite theory for rigid inclusions showed close agreement at low cell volume fraction. The fiber network case exhibited nonlinear stress–strain behavior and Poisson's ratios larger than the elastic limit of 0.5, characteristics similar to those of biological tissues. The second set of simulations used a fiber network for both the cell (simulating cytoskeletal filaments) and matrix, and investigated the effect of varying relative stiffness between the cell and matrix, as well as the effect of a cytoplasmic pressure to enforce incompressibility of the cell. Results showed that the ECM network exerted negligible compression on the cell, even when the stiffness of fibers in the network was increased relative to the cell. Introduction of a cytoplasmic pressure significantly increased the stresses in the cell filament network, and altered how the cell changed its shape under tension. Findings from this study have implications on understanding how cells interact with their surrounding ECM, as well as in the context of mechanosensation.

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