A hybrid analytical–numerical approach for the determination of strain energy release rates in shear deformable functionally graded plates

2022 ◽  
Vol 251 ◽  
pp. 113541
Author(s):  
William E. Guin ◽  
Jialai Wang
Keyword(s):  
Strain Energy ◽  
Strain Energy Release ◽  
Numerical Approach ◽  
Functionally Graded ◽  
Functionally Graded Plates ◽  
Release Rates ◽  
Energy Release Rates ◽  
Strain Energy Release Rates ◽  
Shear Deformable

Three Stages of Fatigue Crack Growth in GFRP Composite Laminates

2000 ◽  
Vol 123 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Jie Tong
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Energy Release ◽  
Crack Growth ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Release Rates ◽  
Energy Release Rates ◽  
Three Stages ◽  
Strain Energy Release Rates

Multiple fatigue crack growth behavior has been studied in model transparent GFRP laminates. Detailed experimental observations have been made on the growth of individual fatigue cracks and on the evolution of cracks in off-axis layers in 0/90/±45S and ±45/90S laminates. Three stages of fatigue crack growth in the laminates have been identified: initiation, steady-state crack growth (SSCG), crack interaction and saturation. The results show that SSCG rate is essentially constant under constant load, independent of crack length and crack spacing. Finite element models have been developed and used to calculate the strain energy release rates associated with the off-axis matrix cracking. A correlation has been achieved between fatigue crack growth rates in off-axis layers and the total strain energy release rates.

A Standard Approach for Measuring Adhesion Energies in Stiction-Failed Microdevices

2006 ◽  
Author(s):  
Zayd C. Leseman ◽  
Steven Carlson ◽  
Xiaojie Xue ◽  
Thomas J. Mackin
Keyword(s):  
Strain Energy ◽  
Peel Test ◽  
Strain Energy Release ◽  
Piezo Actuator ◽  
Release Rates ◽  
Linear Elastic ◽  
Macro Scale ◽  
Energy Release Rates ◽  
Elastic Fracture ◽  
Strain Energy Release Rates

We present results from a new procedure developed to quantify the pull-off force and strain energy release rates associated with stiction-failure in microdevices. The method is analogous to a standard, macro-scale peel test, but carried out using micro-scale devices. Adhesion is initiated by lowering an array of microcantilevers that protrude from a substrate into contact with a separate substrate. Displacement is controlled by a piezo-actuator with sub-nm resolution while alignment is controlled using linear and tilt stages. An interferometric microscope is used to align the array and the substrate and to record deflection profiles and adhesion lengths during peel-off. This geometry is accurately modeled using linear elastic fracture mechanics, creating a robust, reliable, standard method for measuring adhesion energies in stiction-failed microdevices.

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