scholarly journals Effect of Repetitive Collar Replacement on the Residual Strength and Fatigue Life of Retained Hi-Lok Fastener Pins

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 445 ◽  
Author(s):  
David F. Hardy ◽  
David L. DuQuesnay
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Fatigue Life ◽  
Failure Mode ◽  
Residual Strength ◽  
Clamping Force ◽  
Ultimate Shear Strength ◽  
Shear Fatigue ◽  
Static Tensile ◽  
Static Shear

Hi-Lok fasteners were subjected to multiple collar replacements, and were tested under static loading and constant-amplitude fatigue loading, to determine the effect of repetitive collar replacement on the residual strength and fatigue life of a retained Hi-Lok-type fastener pin. Hi-Lok-type fasteners are typically used in aircraft structural joints, and are loaded mainly in shear. Tests were conducted for clamping force, static shear strength, static tensile strength, and shear fatigue life for collars subjected to five collar replacements. The static shear results showed no decrease in the ultimate shear strength of the fastener pin as a function of collar replacement. Static tensile results showed no decrease in the ultimate tensile strength of the fastener as a function of collar replacement, with failure of the aluminum collar remaining the critical failure mode. Similarly, shear fatigue results showed no decrease in the shear fatigue life of the fastened joint as a result of collar replacement, with fracture of the aluminum substrate remaining the critical failure mode. For static shear, static tension, and shear fatigue tests, estimated clamping force was highly consistent between specimens and no decrease in clamping force was observed as a function of collar replacement.

scholarly journals Impact of Reinforcement Ratio on Shear Behavior of I-Shaped UHPC Beams with and without Fiber Shear Reinforcement

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1525 ◽  
Author(s):  
Altug Yavas ◽  
Cumali Ogun Goker
Keyword(s):  
Shear Strength ◽  
Failure Mode ◽  
High Performance Concrete ◽  
Shear Behavior ◽  
Reinforcement Ratio ◽  
Steel Fibers ◽  
Experimental Program ◽  
Shear Reinforcement ◽  
Ultimate Shear Strength ◽  
Loading Test

In the presented paper, the impacts of steel fiber use and tensile reinforcement ratio on shear behavior of Ultra-High Performance Concrete (UHPC) beams were investigated from the point of different tensile reinforcement ratios. In the scope of the experimental program, a total of eight beams consisting of four reinforcement ratios representing low to high ratios ranged from 0.8% to 2.2% were casted without shear reinforcement and subjected to the four-point loading test. While half of the test beams included 30 mm end-hooked steel fibers (SF-UHPC) with 2.0 vol%, the remaining beams were produced without the fiber to show possible effectiveness of the fiber use. The shear performances were discussed in terms of the load—deflection response, cracking pattern and failure mode, first cracking load and ultimate shear strength. In this sense, all the non-fiber beams were failed by shear with a dramatic load drop, regardless of the tensile reinforcement amount, before the yielding of reinforcement and they produced no deflection capability. The test results showed that while the inclusion of steel fibers to the UHPC mixture with low reinforcement ratios changed the failure mode from the shear to flexure, it significantly enhanced the ultimate shear strength in the case of higher reinforcement ratio through the SF-UHPC’ superior mechanical properties and fibers’ crack-bridging ability.

Effect of CO2 Saturation and Desorption on the Fatigue Life of Polycarbonate

1994 ◽  
Vol 116 (4) ◽  
pp. 451-456 ◽  
Author(s):  
K. A. Seeler ◽  
Vipin Kumar
Keyword(s):  
Shear Strength ◽  
Fatigue Life ◽  
Yield Strength ◽  
Fatigue Cracks ◽  
Saturation Pressure ◽  
Stress Relief ◽  
Shear Fatigue ◽  
Static Yield ◽  
Swelling Strain ◽  
Slow Growing

The effect of a cycle of CO2 saturation and desorption on the yield strength, Young’s modulus, and fatigue life of polycarbonate was investigated. The fatigue life of the saturation-cycled polycarbonate exceeded that of unprocessed polycarbonate by up to a factor of thirty. The fatigue life of these rough-surfaced saturation-cycled specimens was approximately equal to or greater than that of polished smooth bar specimens. The increase in fatigue life is a function of the CO2 saturation pressure, reaching a maximum at the same saturation pressure at which there is no further reduction in static yield strength. The increased fatigue life is hypothesized to result from one or more of following mechanisms: (1) reduction of shear strength promoting slow-growing shear fatigue cracks: (2) “healing” or blunting of pre-existing flaws or microcracks by swelling strain or by stress relief strain resulting from plasticization by CO2 during saturation.

Experimental Advances in Effect of Waviness on Properties of Fibre Reinforced Composite Materials

2014 ◽  
Vol 936 ◽  
pp. 82-88 ◽  
Author(s):  
Jun Zhu ◽  
Ji Hui Wang
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Composite Materials ◽  
Failure Mode ◽  
Failure Initiation ◽  
Characterization Techniques ◽  
Reinforced Composite ◽  
Mechanical Performances

Categories, fabrication techniques, characterization techniques, and effect of waviness on properties of fibre reinforced composite materials and structures are reviewed. Waviness exerts a great affluence on properties of composite materials and structures, which leads to a significant degradation or reduction of mechanical performances, such as static compressive/tensile strength, compressive fatigue life, and so on. Various factors related to waviness nested into the composite materials and structures, including wave geometry, thickness position of the wavy layer, percentages of layers with waviness, are considered and stated in detail. Failure mode of laminate containing waviness and the reasons for their failure initiation are analytically stated. At last, some prospects about this study are presented.

scholarly journals Shear Fatigue Performance of Epoxy Resin Waterproof Adhesive Layer on Steel Bridge Deck Pavement

2021 ◽  
Vol 7 ◽  
Author(s):  
Ying Xu ◽  
Xinpeng Lv ◽  
Chunfeng Ma ◽  
Fengming Liang ◽  
Jiafei Qi ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fatigue Life ◽  
Epoxy Resin ◽  
Bridge Deck ◽  
Adhesive Layer ◽  
Fatigue Performance ◽  
Steel Bridge ◽  
Shear Fatigue ◽  
Interlaminar Shear ◽  
Bridge Deck Pavement

In this study, the effects of temperature, shear stress, and coating quantity of waterproof adhesive layer on the shear fatigue performance of a steel bridge deck pavement were investigated. Direct shear fatigue tests of a pavement comprising an epoxy resin waterproof adhesive layer with stone matrix asphalt were conducted at different temperatures, stress levels, and coating quantities. The results show that temperature and stress have significant effects on the shear fatigue life. With increasing temperature and stress, the shear fatigue life of the waterproof adhesive layer decreased gradually. Therefore, for steel bridge deck pavements under high temperatures and heavy loads, the use of asphalt waterproof adhesive layers or pavement layers should be evaluated carefully while limiting the traffic of heavily loaded vehicles. Shear failure occurs at the waterproof adhesive layer–pavement interface and not at the steel–waterproof adhesive layer interface. The shear strength of the epoxy resin waterproof adhesive layer is mainly provided by the bond strength between the waterproof adhesive and pavement mixture as well as the interlocking force between the cured epoxy resin and the bottom interface of uneven pavement mixture. The shear strength increases with the coating quantity of the waterproof adhesive layer; however, after reaching the maximum value, the shear strength becomes stable. In contrast, the interlaminar shear fatigue life increases continuously with the coating quantity of the waterproof adhesive layer. Appropriately increasing the coating quantity is beneficial for improving the resistance of the waterproof adhesive layer to interlaminar shear fatigue failure.

Strength and Energy Absorption of Aluminium Foam under Quasi-Static Shear Loading

2006 ◽  
Vol 312 ◽  
pp. 269-274
Author(s):  
W. Hou ◽  
J. Shen ◽  
Guo Xing Lu ◽  
L.S. Ong
Keyword(s):  
Shear Strength ◽  
Total Energy ◽  
Relative Density ◽  
Energy Absorption ◽  
Shear Force ◽  
Shear Loading ◽  
Maximum Strength ◽  
Ultimate Shear Strength ◽  
Fixed End ◽  
Static Shear

Experiments were carried out to examine the behaviour of aluminium foams under quasistatic shear loading. Special fixtures were designed to clamp the both ends of a beam-like specimen while the load was applied via a punch, which led to failure by shearing along the clearance near the fixed end. Specimens were made of CYMAT foams with two nominal relative densities (12% and 17%) and several values of width. This study focuses on the maximum strength under shear and the essential energy in fracture. It has been found that the ultimate shear force increases linearly with the width of the beam, so does the total energy absorbed. Two empirical formulae have been obtained which relates to the relative density, respectively, the ultimate shear strength and energy absorbed in shearing.

Static shear strength and fatigue life of refill friction stir spot welded AA 6061-T6 sheets

2013 ◽  
Vol 19 (3) ◽  
pp. 214-223 ◽  
Author(s):  
S. Venukumar ◽  
S. G. Yalagi ◽  
S. Muthukumaran ◽  
S. V. Kailas
Keyword(s):  
Shear Strength ◽  
Fatigue Life ◽  
Friction Stir ◽  
Static Shear ◽  
Spot Welded

scholarly journals Effect Surface Roughness on Fatigue Crack Propagation Behaviour of Fibre Metal Laminates (FMLs)

2019 ◽  
Vol 16 (2) ◽  
pp. 6588-6604
Author(s):  
A. Purnowidodo ◽  
S. Sofyan Arief ◽  
F. Hilmi Iman
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Shear Strength ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Fibre Orientation ◽  
Interface Shear ◽  
Fibre Metal Laminates ◽  
Fibre Metal ◽  
Effect Of Surface

In the present study, the effect of surface roughness of the metal lamina at the interface of fibre metal laminates (FMLs) on the crack propagation behaviours was investigated for different fibre orientation. The FMLs was made by combining the aluminium and the carbon fibre-epoxy composite lamina. The increasing of the aluminium surface roughness at the interface causes the tensile strength to increase for every fibre orientation. The highest tensile strength is 282 and 367 MPa., respectively for fibre orientation 0°/90° and -45°/45° when the surface roughness is 2.89 mm. The increasing surface roughness causes the development of the delamination taking place at the interface is more difficult, and it leads to the shear strength at the interface to increase. Because of this, the tensile strength increases. However, the lifetime is not only influenced by the interface shear strength but also the stress concentration just in front of the crack tip as well as the surface roughness itself leading to the crack to be initiated from the rougher surface. The longest fatigue life is 180 000 cycles in the case of the fibre orientation 0°/90° with the surface roughness of 1.78 mm, and in the case of fibre orientation of -45°/+45° the longest fatigue life is 420 000 cycles when the surface roughness is 0.33 mm. The results of the study show that the surface roughness affects the tensile strength and crack propagation behaviour.

Effects of stabilization patterns on the static and fatigue behavior of glass fiber non-crimp fabric composites

2019 ◽  
Vol 53 (25) ◽  
pp. 3589-3598
Author(s):  
Sana Ullah Nasir ◽  
Asim Shahzad
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Glass Fiber ◽  
Volume Fraction ◽  
Fatigue Behavior ◽  
Experimental Studies ◽  
Tensile Modulus ◽  
Fatigue Properties ◽  
Fabric Composites ◽  
Static Tensile

Experimental studies have been conducted to evaluate static tensile and tension–tension fatigue response of unidirectional glass fiber non-crimp fabric composites subject to seven different stabilization patterns (two multiaxial and five uniaxial stabilizing yarns). The effect of stabilization patterns on non-crimp fabric is crucial as they produce different mesoscale bundle shapes and bundle volume fractions which may affect the static and fatigue properties of non-crimp fabric composites. The studies show that tensile modulus and fatigue life decline with increasing amount of uniaxial stabilizations. Different stabilizations with different bundle shapes influence the final composite properties through various factors than just the volume fraction. The multiaxial stabilizations with higher static tensile strength have shorter fatigue life as compared to uniaxial stabilizations with lower tensile strength. As the areal weight of stabilizing yarns increases, fatigue life decreases at all stress levels which show the deleterious effects of stabilizations on the fatigue behavior of composites. Areal weight and orientation of stabilizing yarns should be optimally selected for the anticipated performance of the non-crimp fabric composites.

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