scholarly journals Caracterização da tenacidade à fratura de materiais de fricção e critérios de projetos

Exacta ◽  
2011 ◽  
Vol 9 (3) ◽  
pp. 301-308
Author(s):  
Alexandre Casaril ◽  
Carlos Henrique Selle Pereira ◽  
Carlos Pérez Bergmann ◽  
Hazim Ali Al-Qureshi
Keyword(s):  
Fracture Toughness ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Plane Strain Fracture Toughness ◽  
Plastic Materials ◽  
Strain Fracture

Este trabalho foi realizado com objetivo de caracterizar materiais de fricção atualmente utilizados em veículos pesados para linha de montagem e reposição. Cinco materiais de fricção foram analisados através de testes mecânicos realizados com base na norma ASTM D5045-99 (Reapproved 2007) – Plane Strain Fracture Toughness and Strain Energy Release Rate of plastic Materials. Os resultados de KIC dos cinco materiais foram da ordem de 1 MPa.m1/2, corroborando com o esperado para materiais de matriz fenólica. Adicionalmente, os resultados de KIC são representativos da fragilidade dos materiais de fricção. A análise estatística foi realizada utilizando a metodologia de Weibull, permitindo estabelecer probabilidades de ocorrência de KIC menor do que um valor aleatoriamente escolhido. Dessa forma, do ponto de vista de projeto é possível estabelecer critérios de falha, evitando o investimento de recursos em protótipos que venham a falhar em campo.

Mode I Fracture Toughness of a Tri-Layered Beam with Interfacial Crack

2012 ◽  
Vol 166-169 ◽  
pp. 245-248
Author(s):  
Shiuh Chuan Her ◽  
Wei Bo Su
Keyword(s):  
Fracture Toughness ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Mode I ◽  
Analytical Prediction ◽  
Layered Beam

A tri-layered cracked beam under opening loading is developed for the interfacial fracture toughness measurement. Determination of the mode I strain energy release rate along the second and third layers of the tri-layered beam is carried out analytically. The analytical prediction of the strain energy release rate is validated with the finite element results. The influences of the layer thickness and Young’s modulus on the strain energy release rate are examined through a parametric study.

scholarly journals Toughening of Epoxy Resin: The Effect of Water Jet Milling on Worn Tire Rubber Particles

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 529 ◽  
Author(s):  
Peter Tamas-Benyei ◽  
Eniko Bitay ◽  
Hajime Kishi ◽  
Satoshi Matsuda ◽  
Tibor Czigany
Keyword(s):  
Fracture Toughness ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Charpy Impact ◽  
Strain Energy Release ◽  
Water Jet ◽  
Rubber Particles

In this work a cycloaliphatic amine-cured epoxy (EP) resin was modified by micron-scale rubber particles (RP). Nominal RP, in sizes of 200 and 600 µm respectively, were produced using worn truck tires and ultra-high-pressure water jet cutting. The RP were dispersed into the EP resin using different mixing techniques (mechanical, magnetic, and ultrasonic stirring) prior to the introduction of the amine hardener. The dispersion of the RP was studied using optical light microscopy. A longer mixing time reduced the mean size of the particles in the EP compounds. Static (tensile and flexural), dynamic (unnotched Charpy impact), and fracture mechanical (fracture toughness and strain-energy release rate) properties were determined. The incorporation of the RP decreased the stiffness and strength values of the modified EPs. In contrast, the irregular and rough surface of the RP resulted in improved toughness. The fracture toughness and strain-energy release rate were enhanced up to 18% owing to the incorporation of 1% by weight (wt%) RP. This was traced to the effects of crack pinning and crack deflection. Considerably higher improvement (i.e., up to 130%) was found for the unnotched Charpy impact energy. This was attributed to multiple cracking associated with RP-bridging prior to final fracture.

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