Methods for Determining the Mode I and Mode II Fracture Toughness of Glass Using Thermal Stresses

1990 ◽  
Vol 112 (2) ◽  
pp. 151-156 ◽  
Author(s):  
J. T. Gillanders ◽  
R. A. Riddle ◽  
R. D. Streit ◽  
I. Finnie
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Thermal Stresses ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Mode I ◽  
Mode Ii ◽  
Average Value ◽  
Mode Ii Fracture Toughness ◽  
Free Environment

The fracture toughness of soda-lime glass was measured by applying thermal stresses to center-cracked plates. Mode I cracking was achieved by chilling the crack faces. The stress intensity factor was obtained by combining temperature measurements with a finite element solution. The average value of KIC = 0.77 MN/m3/2 based on three tests agrees well with values in the literature for a water-free environment. Mode II cracking was achieved by applying a temperature gradient normal to the crack. A value KIIC = 1.6 MN/m3/2 was obtained in two tests using a finite element computation based on the temperature distribution computed from the specimen’s thermal boundary conditions.

Comparison of mode I and mode II fracture toughness of an 8090 AlLi alloy

1991 ◽  
Vol 149 (1) ◽  
pp. L1-L3 ◽  
Author(s):  
S.V. Kamat ◽  
N. Eswara Prasad ◽  
G. Malakondaiah
Keyword(s):  
Fracture Toughness ◽  
Mode I ◽  
Mode Ii ◽  
Mode Ii Fracture ◽  
Mode Ii Fracture Toughness

scholarly journals Influence of Particle Size on Toughening Mechanisms of Layered Silicates in CFRP

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2396
Author(s):  
Julia Hutschreuther ◽  
Raphael Kunz ◽  
Josef Breu ◽  
Volker Altstädt
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Carbon Fiber ◽  
Layered Silicates ◽  
The Other ◽  
Mode I ◽  
Mode Ii ◽  
Carbon Fiber Composites ◽  
Toughening Mechanisms ◽  
Mode Ii Fracture Toughness

Carbon-fiber-reinforced epoxies are frequently used for lightweight applications that require high mechanical properties. Still, there is potential regarding the improvement of the interlaminar-fracture toughness. As matrix toughening with nanoparticles is one possibility, in this study two different layered silicates are used to reinforce carbon fiber composites. The first type is a synthetical K-Hectorite (K-Hect) with outstanding lateral extension (6 µm) that has shown high toughening ability in resins in previous work. The other is a commercial montmorillonite (MMT) with a smaller size (400 nm). The aim of this study is to show the influence of the particles on mode I and mode II fracture toughness, especially the influence of particle size. Therefore, double-cantilever-beam tests and end-notched-flexure tests were carried out. Additionally, the fracture mechanisms were investigated via scanning electron microscopy (SEM). It is concluded, that the larger Hectorite particles are beneficial for mode I fracture behavior because of enhanced toughening mechanisms. One the other hand, the mode II energy dissipation rate is increased by the smaller montmorillonite particles due to sufficient interaction with the formation of hackling structures.

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