Analysis of the damage zone around the crack tip for two rubber-modified epoxy matrices exhibiting different toughenability

Polymer ◽  
2003 ◽  
Vol 44 (5) ◽  
pp. 1537-1546 ◽  
Author(s):  
Marı́a L Arias ◽  
Patricia M Frontini ◽  
Roberto J.J Williams
Keyword(s):  
Damage Zone ◽  
Crack Tip ◽  
Epoxy Matrices ◽  
Modified Epoxy

Damage Zone Around Tip of an Interface Crack Between Rubber-Modified Epoxy Resin and Aluminum

2002 ◽  
Vol 124 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Deok-Bo Lee ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki ◽  
Nak-Sam Choi
Keyword(s):  
Residual Stress ◽  
Epoxy Resin ◽  
Interface Crack ◽  
Significant Influence ◽  
Fracture Behavior ◽  
Structural Integrity ◽  
Damage Zone ◽  
Crack Tip ◽  
Rubber Particles ◽  
Modified Epoxy

The fracture behavior of an interface crack tip has significant influence on the structural integrity of an adhesive joint. We investigate a damage zone and the deformation of rubber particles around a tip of an interface crack between rubber-modified epoxy resin and aluminum. They are compared with those around a crack tip in homogeneous rubber-modified epoxy resin. Cavitations in rubber particles are observed around a damaged crack tip in homogeneous resin but not around a damaged interface crack tip. Rubber particles around an interface crack tip are deformed ellipsoidally due to the residual stress even before being damaged, and interfaces between rubber particles and epoxy resin around an interface crack tip are debonded after being damaged.

Damage zone around crack tip and fracture toughness of rubber-modified epoxy resin under mixed-mode conditions

2002 ◽  
Vol 69 (12) ◽  
pp. 1363-1375 ◽  
Author(s):  
Deok-Bo Lee ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki ◽  
Nak-Sam Choi
Keyword(s):  
Fracture Toughness ◽  
Epoxy Resin ◽  
Mixed Mode ◽  
Damage Zone ◽  
Crack Tip ◽  
Modified Epoxy

Effect of Bond Thickness on the Fracture Toughness of Adhesive Joints

2004 ◽  
Vol 126 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Deok-Bo Lee ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki ◽  
Nak-Sam Choi
Keyword(s):  
Fracture Toughness ◽  
Adhesive Joint ◽  
Damage Zone ◽  
Crack Tip ◽  
Adhesive Layer ◽  
Compact Tension ◽  
Optical Microscope ◽  
Adhesive Joints ◽  
Adhesive Layers ◽  
Modified Epoxy

The effect of bond thickness on the fracture toughness of adhesive joints was investigated from a microstructural perspective, using compact tension (CT) adhesive-joint specimens with different bond thicknesses. The adhesive material was a rubber-modified epoxy resin with 12.5 wt% carboxy-terminated butadiene acrylonitrile (CTBN) elastomer. The shapes of the rubber particles dispersed in adhesive layers of damaged and undamaged specimens were observed with an optical microscope. The damage was distributed along the interfaces between the adhesive layer and the two adherends. The results show that the primary causes of variations in the fracture toughness of an adhesive joint with the bond thickness are not only a damage zone around a crack tip but also the combination of a damage zone around a crack tip and additional damage zones along the interfaces.

Failure Analysis on Rubber-Modified Epoxy Resin under Various Loading Speed Conditions

2005 ◽  
Vol 297-300 ◽  
pp. 1907-1912 ◽  
Author(s):  
Deok Bo Lee ◽  
Joo Hyung Kim
Keyword(s):  
Fracture Toughness ◽  
Composite Material ◽  
Epoxy Resin ◽  
Structural Reliability ◽  
Fiber Composite ◽  
Damage Zone ◽  
Crack Tip ◽  
Rubber Content ◽  
The Matrix ◽  
Modified Epoxy

A rubber-modified epoxy resin is widely used as adhesive and matrix materials for fiber composite material. The structural reliability of composite material depends on the fracture toughness of the matrix resin. In this study, the fracture toughness and the damage zone around a crack tip in rubber-modified epoxy resin were investigated. The volume fractures of rubber (CTBN1300×8) in the rubber-modified epoxy resin were 0%, 5% and 15% under several loading speeds. The fracture toughness(KIC) and the fracture energy(GIC) were measured by using 3-point bending specimens. The 4-point bending specimens were also used to observe damage zones at the vicinity of a crack tip in modified resins. The results show that the values of the fracture toughness and the sizes of damage zones at 5% and 15% rubber content decrease with increase in loading speed.

Finite Element Modeling of Damage Formation in Rubber-Toughened Polymer

2005 ◽  
Vol 297-300 ◽  
pp. 1019-1024
Author(s):  
Mitsugu Todo ◽  
Yoshihiro Fukuya ◽  
Seiya Hagihara ◽  
Kazuo Arakawa
Keyword(s):  
Finite Element ◽  
Damage Zone ◽  
Damage Model ◽  
Crack Tip ◽  
Optical Microscope ◽  
Toughening Mechanism ◽  
Element Analysis ◽  
Zone Formation ◽  
Macro Scale ◽  
Rubber Toughened

Microscopic studies on the toughening mechanism of rubber-toughened PMMA (RTPMMA) were carried out using a polarizing optical microscope (POM) and a transmission electron microscope (TEM). POM result showed that in a typical RT-PMMA, a damage zone was developed in the vicinity of crack-tip, and therefore, it was considered that energy dissipation due to the damage zone development was the primary toughening mechanism. TEM result exhibited that the damage zone was a crowd of micro-crazes generated around rubber particles in the vicinity of notch-tip. Finite element analysis was then performed to simulate such damage formations in crack-tip region. Macro-scale and micro-scale models were developed to simulate damage zone formation and micro-crazing, respectively, with use of a damage model. It was shown that the damage model introduced was successfully applied to predict such kind of macro-damage and micro-craze formations.

Characterization of Crack Tip Damage Zone Formation on Alloy 625 During Fatigue Crack Growth at 750°C by Transmission EBSD Method

2017 ◽  
Author(s):  
Yuji Ozawa ◽  
Tatsuya Ishikawa ◽  
Yoichi Takeda
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Power Plants ◽  
Crack Path ◽  
Damage Zone ◽  
Crack Tip ◽  
Loading Frequency ◽  
Zone Formation ◽  
Alloy 625

In order to clarify the mechanism of fatigue crack growth in alloy 625, which is a candidate material for use in advanced ultra supercritical power plants, the crack tip damage zone formation after a crack growth test conducted in high temperature steam was investigated. It was observed that the oxide thickness at the crack tip tended to increase with decreasing cyclic loading frequency. The crack path was a mix of transgranular and intergranular fractures. According to the grain reference orientation deviation (GROD) maps, it was revealed that the density of geometrically necessary dislocations (GNDs) in the matrix along the crack path and ahead of crack tip increased with an increase in the fatigue crack growth rate (FCGR) due to environmental effects. It was observed that (1) mobile dislocations at the crack surface were blocked due to the thick oxide layer, resulting in an increase in the density of GNDs, and (2) an increase in the density of GNDs might induce stress concentration at the crack tip, deformation twinning, and the acceleration of FCGRs.

Preparation and properties of high performance phthalide-containing bismaleimide modified epoxy matrices

2011 ◽  
Vol 121 (6) ◽  
pp. 3122-3130 ◽  
Author(s):  
Xuhai Xiong ◽  
Ping Chen ◽  
Jinxiang Zhang ◽  
Qi Yu ◽  
Baichen Wang
Keyword(s):  
High Performance ◽  
Epoxy Matrices ◽  
Modified Epoxy
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