Showing papers on "Stress concentration published in 2009"
TL;DR: In this paper, a series of three-dimensional semi-elliptical pitted models were used to investigate the effect of pit aspect ratio on stress concentration factor (SCF) under uniaxial tension loading.
222 citations
TL;DR: In this paper, the tensile elastic modulus of a rock is calculated by measuring tensile strain on the center part of a Brazilian disc's two side faces along the direction perpendicular to the line load, and then the force sensor is used to record the force applied; finally the E t can be calculated according to those related formulas which are derived on the basis of elasticity theory.
170 citations
TL;DR: In this article, the effects of various surface treatment techniques on the fatigue crack growth performance of friction stir welded 2195 aluminum alloy were investigated and the effect of the compressive stresses was deemed responsible for increasing the resistance to fatigue cracks.
152 citations
TL;DR: In this article, a welding simulation procedure is developed using the FE software ANSYS in order to predict residual stresses and their relaxation during crack propagation by isoparametric stress mapping between meshes without and with cracks.
150 citations
TL;DR: It is believed that cross-linked UHMWPE remains an excellent bearing material for total hip replacements but that designs employing this material should mitigate stress concentrations or other design features that increase the risk of fracture.
149 citations
TL;DR: In this paper, a periodic asymmetric hexagonal perforation pattern was cut into thin Ti-6Al-4V sheets which were then folded along node rows by a combination of partial low-temperature bending followed by simultaneous hot forming/diffusion bonding to form sandwich panel structures with core relative densities of 1.0-4.1%.
144 citations
TL;DR: In this article, the effect of shot peening on the reverse bending fatigue behavior of Al-7075-T651 was investigated by means of X-ray diffraction (XRD) measurements.
143 citations
TL;DR: In this paper, the role of longitudinal residual stress on propagation of fatigue cracks was examined in friction stir welds produced in 2024-T351 aluminum alloy and it was found that residual stresses correspond to low crack growth rates outside the weld zone during fatigue loading.
139 citations
TL;DR: In this article, the authors investigated the fatigue properties of bainitic 100Cr6 (SAE 52100, JIS SUJ2) steel in the high cycle and very high cycle fatigue (VHCF) regime.
123 citations
TL;DR: In this article, epoxy adhesive joints of different thicknesses between aluminium substrates have been characterized using physico-chemical analyses (differential scanning calorimetry, DSC; dynamic mechanical analysis, DMA; spectroscopy), nano-indentation and mechanical testing.
121 citations
TL;DR: In this article, the effect of an increase in the oil volume fraction ( φ ) on the Young's modulus was studied for all gels according to the Van der Poel theory, and the relative impact was related to the viscoelastic properties of the gels and to droplet-matrix interaction.
TL;DR: In this article, the notch stress intensity factor (NSIF) based analytical frame is applied to the slit tips (or weld roots) of welded joints with inclusion of the T-stress component.
Abstract: The notch stress intensity factor (NSIF) based analytical frame is applied to the slit tips (or weld roots) of welded joints with inclusion of the T-stress component. This T-stress can be determined from FE models evaluating the ligament stresses close to the pointed slit tip. An alternative analytical frame is presented for the corresponding keyhole notches based on analytical solutions from the literature, which are applied to the ligament stresses.
In the slit tip models, the mean local strain energy density (SED) with inclusion of the T-stress effect is determined analytically and numerically in comparison, using two different fatigue-relevant control radii, R0= 0.28 mm and R0= 0.15 mm, the former value well proven for thick-sheet welded joints made of structural steel. The latter smaller value is tentatively proposed for thin-sheet welded joints, in the direction suggested in the recent literature where a reduction of the microstructural support length for laser beam welds and resistance spot welds is recommended. The FEM-based and analytical stress concentration factors (SCF) for the lap joint keyhole model and also the SED values for the corresponding pointed slit tips are found to be in good agreement. The J-integral consisting of the first and second component (the latter containing the T-stress) is compared with the corresponding SED values.
TL;DR: In this article, a damage-based cohesive model is developed for simulating crack growth due to fatigue loading, which follows a linear damage-dependent traction-separation relation coupled with a damage evolution equation.
TL;DR: In this article, the authors present a theoretical framework for the stress analysis of adhesively bonded tubular lap joint based on a variational principle which minimizes the complementary energy of the bonded system.
TL;DR: In this article, the S-N curve of high carbon-chromium bearing steel was investigated under axial loading fatigue in the very high cycle fatigue regime, and three fracture modes were observed on the fracture surface, such as surface-induced fracture, subsurface inclusion induced fracture without granular bright facet (GBF) area and that with GBF area around an inclusion.
TL;DR: In this paper, the authors compare and evaluate the stress distribution of three NiTi instruments of various cross-sectional configurations under bending or torsional condition using a finite-element analysis model.
Abstract: Aim To compare and evaluate the stress distribution of three NiTi instruments of various cross-sectional configurations under bending or torsional condition using a finite-element analysis model.
Methodology Three NiTi files (ProFile, ProTaper and ProTaper Universal) were scanned using Micro-CT to produce a three-dimensional digital model. The behaviour of the instrument under bending or torsional loads was analysed mathematically in software (ABAQUS V6.5-1), taking into consideration the nonlinear mechanical characteristic of NiTi material.
Results ProFile showed the greatest flexibility, followed by ProTaper Universal and ProTaper. The highest stress was observed at the surface near the cutting edge and the base of (opposing) flutes during cantilever bending. Concentration of stresses was observed at the bottom of the flutes in ProFile and ProTaper Universal instruments in torsion. The stress was more evenly distributed over the surface of ProTaper initially, which then concentrated at the middle of the convex sides when the amount of angular deflection was increased.
Conclusion Incorporating a U-shaped groove in the middle of each side of the convex-triangular design lowers the flexural rigidity of the origin ProTaper design. Bending leads to the highest surface stress at or near the cutting edge of the instrument. Stress concentration occurs at the bottom of the flute when the instrument is subjected to torsion.
TL;DR: In this paper, the interfacial shear strength between epoxy and carbon fibers, measured from microdroplet specimens adhered onto a single carbon fiber, was analyzed using finite element analysis of the droplet, sphere and cylinder model types.
TL;DR: In this paper, the most important current approaches for residual strength prediction of thin-walled structures are reviewed and discussed with respect to their benefits and limitations for the simulation of plane and stiffened panels.
TL;DR: In this paper, a computational model for contact fatigue damage analysis of gear teeth flanks is presented, which considers the conditions required for the surface fatigue crack initiation and then allows for proper simulation of the fatigue crack propagation that leads to the appearance of small pits on the contact surface.
SIDI1
TL;DR: In this article, an improved solution for interfacial stresses in a concrete beam bonded with the FRP plate by including the effect of the adherend shear deformations is presented, where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness.
TL;DR: In this paper, the effects of high concentrations of thermally precharged hydrogen as well as crack growth orientation and ferrite content on fracture initiation toughness of stainless steel forgings were investigated.
TL;DR: In this paper, the local anodic dissolution behavior of smooth and pre-cracked X70 pipeline steel specimens under applied tensile stress was investigated by micro-electrochemical measurements and numerical simulation.
TL;DR: In this article, a computational strategy is developed to characterize the driving force for fatigue crack nucleation at subsurface primary inclusions in carburized and shot peened C61® martensitic gear steels.
TL;DR: In this paper, the effect of torque tightening a nut and bolt on the fracture strength and the stress intensity geometry factor of a fastener hole containing a symmetrical pair of edge cracks was investigated.
TL;DR: In this article, a two-parameter fatigue crack growth model based on the local stress-strain material behaviour at the crack tip was used to account for the variable amplitude loading effects.
TL;DR: In this paper, the authors investigated the influence of specimen thickness on closure behavior and on fatigue crack propagation in CT CT specimens with different thicknesses using traditional compliance techniques (clip gauge and back face strain gauge) and Digital Image correlation methods.
TL;DR: In this article, the authors derived the SI of sharp rounded V-notches by means of Filippi's equations and considering different failure criteria (Rankine, von Mises and Beltrami) for different notch opening angles as a function of the actual notch radius and the microstructural support length.
TL;DR: In this article, the effect of precorrosion on the fatigue life of aluminum alloy 7075-T6511 was measured, physical characteristics of corrosion topography plus fatigue damage were established by microscopy, and a corrosion modified equivalent initial flaw size (CM-EIFS) was established using fracture mechanics modeling.
TL;DR: In this paper, the interaction between residual stress and fatigue crack growth rate has been investigated in middle tension and compact tension specimens machined from a variable polarity plasma arc welded aluminium alloy 2024-T351 plate.
TL;DR: In this paper, the authors deal with online controlled propagation and vibration-based detection of fatigue cracks in metal beams constituted of two different materials: 6082-T651 aluminium alloy and Fe430 steel.
Abstract: This paper deals with online controlled propagation and vibration-based detection of fatigue cracks in metal beams constituted of two different materials: 6082-T651 aluminium alloy and Fe430 steel....