Microstructural damage and fracture mechanisms of selective laser melted Al-Si alloys under fatigue loading

2020 ◽  
Vol 106 ◽  
pp. 102483 ◽  
Author(s):  
Mustafa Awd ◽  
Shafaqat Siddique ◽  
Frank Walther
Keyword(s):  
Fatigue Loading ◽  
Fracture Mechanisms ◽  
Microstructural Damage ◽  
Damage And Fracture

Simulation of Impact Damage in Foam-Based Sandwich Composites

2013 ◽  
Vol 569-570 ◽  
pp. 25-32
Author(s):  
Dian Shi Feng ◽  
Francesco Aymerich
Keyword(s):  
Impact Damage ◽  
Element Model ◽  
Fracture Mechanisms ◽  
Sandwich Composites ◽  
Typically Developing ◽  
Damage Resistance ◽  
Damage And Fracture ◽  
Closed Cell ◽  
Impact Energies ◽  
The Impact

The paper describes the application of a 3D finite element model for prediction of impact induced damage in sandwich composites consisting of laminated skins bonded to a closed cell foam core. The major damage and fracture mechanisms typically developing in transversally loaded sandwich composites were simulated in the model. The model was implemented in the FE package ABAQUS/Explicit and used to predict the impact damage resistance of sandwich panels with different core densities, core thicknesses, and skins layups. Numerical results obtained by FE simulations were compared with experimental data and observations collected through impact tests carried out at various impact energies.

Damage and Fracture Mechanisms during Mode I and III Loading of Wood

Holzforschung ◽  
2001 ◽  
Vol 55 (5) ◽  
pp. 525-533 ◽  
Author(s):  
E.K. Tschegg ◽  
K. Frühmann ◽  
S.E. Stanzl-Tschegg
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Fracture Energy ◽  
Fracture Mechanisms ◽  
Mode I ◽  
Mode Iii ◽  
Initiation Energy ◽  
Specific Fracture Energy ◽  
Damage And Fracture ◽  
Specific Fracture

Summary Tests under mode I and mode III loading were performed on side grooved Compact-Tension specimens of larch and beech under steady state crack propagation to study the damage and fracture behaviour and the influence of two fibre orientations. From the complete load-displacement diagram, all important damage and fracture mechanical values (stiffness/compliance, microstructural damage, crack initiation energy, specific fracture energy, etc.) have been determined. Crack initiation energy and specific fracture energy are approximately ten times higher for mode III loading than for mode I loading in both wood species. Crack initiation occurs in mode III under external mode III loading, crack propagation, however, takes place under mode I, owing to crack surface interference. The influence of fibre orientation on the (fracture) mechanical properties of beech and larch is different. This difference may be explained mainly by the high number of rays in beech.

Investigation on Fatigue Damage and Fracture of Al-5Zn-2Mg High Strength Aluminum Alloy

2012 ◽  
Vol 184-185 ◽  
pp. 1030-1033 ◽  
Author(s):  
Shang Lei Yang ◽  
Qin Lin Lin ◽  
Chao Xu ◽  
Jia Hui Pan
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Average Rate ◽  
High Strength ◽  
Fatigue Loading ◽  
Optical Microscope ◽  
Fatigue Properties ◽  
High Strength Aluminum Alloy ◽  
Damage And Fracture ◽  
Micro Cracks

The tensile properties and fatigue properties were tested, and the fatigue fracture and damage behaviore of Al-5Zn-2Mg high strength aluminum alloy was investigated by means of optical microscope (OM) and scanning electron microscope (SEM). The results show that the grain of the Al-5Zn-2Mg high strength aluminum alloy is elongated after rolling deformation. The tensile strength of the Al-5Zn-2Mg aluminum alloy is 470MPa. The fatigue life is 6.4×104 cycle in R=0.1, f=99Hz, and σmax=210MPa. The average rate is 0.08μm per cycle from micro crack formed to 8mm of fatigue crack length. The fatigue crack forms in the surface. There are the fatigue striations in the fatigue crack propagation area. The crack velocity is about 2μm per cycle in propagation area. The damaged microstructure with the fatigue loading is loose, that indicates the micro cracks progressively emerge.

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