Failure Mode and Fatigue Behavior of Flow Drill Screw Joints in Lap-Shear Specimens of Aluminum 6082-T6 Sheets of Different Thicknesses

2018 ◽  
Vol 11 (4) ◽  
pp. 315-326 ◽  
Author(s):  
Jwo Pan ◽  
Wei-Ning Chen ◽  
Shin-Jang Sung ◽  
Xuming Su ◽  
Peter Friedman
Keyword(s):  
Failure Mode ◽  
Fatigue Behavior ◽  
Lap Shear

Investigation of Failure Mode and Fatigue Behavior of Flow Drill Screw Joints in Lap-Shear Specimens of Aluminum 6082-T6 Sheets

2016 ◽  
Vol 9 (3) ◽  
pp. 746-750 ◽  
Author(s):  
Seung Hoon Hong ◽  
Frank Yan ◽  
Shin-Jang Sung ◽  
Jwo Pan ◽  
Xuming Su ◽  
...  
Keyword(s):  
Failure Mode ◽  
Fatigue Behavior ◽  
Lap Shear

Failure Mode and Fatigue Behavior of Dissimilar Laser Welds in Lap-Shear Specimens of Aluminum and Copper Sheets

2014 ◽  
Vol 7 (3) ◽  
pp. 706-710 ◽  
Author(s):  
Wei-Jen Lai ◽  
Shin-Jang Sung ◽  
Jwo Pan ◽  
Yunan Guo ◽  
Xuming Su
Keyword(s):  
Failure Mode ◽  
Fatigue Behavior ◽  
Lap Shear ◽  
Laser Welds

scholarly journals Microstructure and mechanical properties of an ultrasonic spot welded aluminum alloy: the effect of welding energy

2021 ◽  
Author(s):  
He Peng ◽  
Daolun Chen ◽  
Xianquan Jiang
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
Cyclic Loading ◽  
Crack Growth ◽  
Failure Mode ◽  
Spot Welding ◽  
Energy Levels ◽  
Lap Shear Strength ◽  
Pull Out ◽  
Lap Shear

The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique–ultrasonic spot welding (USW)–at different energy levels. An ultra-fine necklace-like equiaxed grain structure is observed along the weld line due to the occurrence of dynamic crystallization, with smaller grain sizes at lower levels of welding energy. The tensile lap shear strength, failure energy, and critical stress intensity of the welded joints first increase, reach their maximum values, and then decrease with increasing welding energy. The tensile lap shear failure mode changes from interfacial fracture at lower energy levels, to nugget pull-out at intermediate optimal energy levels, and to transverse through-thickness (TTT) crack growth at higher energy levels. The fatigue life is longer for the joints welded at an energy of 1400 J than 2000 J at higher cyclic loading levels. The fatigue failure mode changes from nugget pull-out to TTT crack growth with decreasing cyclic loading for the joints welded at 1400 J, while TTT crack growth mode remains at all cyclic loading levels for the joints welded at 2000 J. Fatigue crack basically initiates from the nugget edge, and propagates with “river-flow” patterns and characteristic fatigue striations. Keywords: aluminum alloy; ultrasonic spot welding; EBSD; microstructure; tensile strength; fatigue

Surface Topography Influences on the Fatigue Behavior of Composite Joints

2019 ◽  
Vol 809 ◽  
pp. 341-346 ◽  
Author(s):  
Torsten Thäsler ◽  
Jens Holtmannspötter ◽  
Hans Joachim Gudladt
Keyword(s):  
Bond Strength ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Surface Condition ◽  
Atmospheric Pressure Plasma ◽  
Fatigue Tests ◽  
Stress Concentrations ◽  
Release Agent ◽  
Structured Surfaces ◽  
Lap Shear

The surface condition of carbon fibre reinforced plastic (CFRP) substrates is decisive to obtain high bond strength and lifetime of adhesively bonded parts. Those surfaces were adjusted in terms of their microscopic topography by means of peel plies and release foils. The subsequent surface treatment via atmospheric pressure plasma jet or vacuum blasting allowed the modification of the microscopic roughness as well as the surface chemistry. Those configuration were assessed using surface analytic methods as well as quasi-static and cyclic fracture tests on single lap shear specimens. The microscopic surface roughness, if at all, only showed a small influence on the bond strength. Despite release agent residues, fracture was found within the fiber-matrix interface, which caused difficulties in evaluating the effect of surface pretreatments on the adhesion strength. Fatigue tests revealed a lifetime reduction of uneven microscopic rough surfaces, which was assigned to stress concentrations at the tip of asperities. The crack propagation was accelerated in case of release agent residues. If surfaces were free of contaminations, no differences between microscopically smooth and slightly structured surfaces were found. Overall, fatigue testing on single lap shear specimens showed an increased sensitivity with regard to the assessment of surface morphology.

Bond Behaviour of FRCM Composites: Effects of High Temperature

2019 ◽  
Vol 817 ◽  
pp. 161-166
Author(s):  
Antonio Iorfida ◽  
Sebastiano Candamano ◽  
Fortunato Crea ◽  
Luciano Ombres ◽  
Salvatore Verre ◽  
...  
Keyword(s):  
High Temperature ◽  
Failure Mode ◽  
Failure Modes ◽  
Construction Materials ◽  
Mechanical Damage ◽  
High Density ◽  
Bond Behaviour ◽  
Bond Slip ◽  
Masonry Construction ◽  
Lap Shear

The fire remains one of the serious potential risks to most buildings and structures, as recently it’s been witnessed in Paris’ historic Notre Dame Cathedral and London’s Grenfell Tower. Concrete and masonry construction materials suffer physiochemical changes and mechanical damage caused by heating that is usually confined to the outer surface but can eventually compromise their load-bearing capacity. FRCM systems could provide when applied, supplemental fire insulation on pre-existing structural members, but there is a lack of knowledge about their properties in those conditions. This experimental work, thus, aims to evaluate the mechanical behaviour of carbon-FRCM and basalt-FRCM composites bonded to masonry substrate after high temperature exposure. Temperatures of 100 °C, 300 °C and 500 °C over a period of three hours were used to investigate the degradation of their mechanical properties. Single lap shear bond tests were carried out to evaluate the bond-slip response and failure modes. For all the tested temperatures higher peak stresses were measured for carbon-FRCM composite than basalt ones. Furthermore, low-density basalt-FRCM composite showed higher peak stresses and lower global slips up to 300 °C than high-density one. Carbon-FRCM composite failure mode was not effected by temperature. High-density basalt-FRCM composite showed a change in failure mode between 300 °C and 500 °C.

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