Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Strain

Strain Behavior at Crack Tip in Thin Plate Using Numerical and Experimental Work

Bassam Ali Ahmed; Fathi A.Alshamma

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 513-526

In this work, strains were studied and analyzed in a thin flat plate with a surface crack at the center, subjected to cycling of low velocity impact loading for two types of aluminum plates (2024, 6061). Experimental and numerical methods were implemented to achieve this research. Two cases of boundary conditions were used in this study; clamped-clamped with simply supported at the other edges, and clamped-clamped with free at the other edges. Numerical analysis using program (ANSYS11-APDL) based on finite element method used to analyze the strains with respect to time at crack tip. In the experimental work, a rig was designed and manufactured for cyclic impact loading on the cracked specimens. The grid points was screened in front of the crack tip to measure the elastic-plastic displacements in the x and y directions by grid method, from which the strains are calculated. The results show that the strains increase with increasing the crack length. It was found that the cumulative number of cycles leads to increase in the strain values.

Mechanical and Tribological Behavior of Glass- Polyester Composite System under Graphite Filler Content

Farag M. Mohammed; Drai A. Smait

Engineering and Technology Journal, 2012, Volume 30, Issue 4, Pages 672-683

Experimental investigations had been done in this work to demonstrate the effect of
graphite filler contents on the mechanical and tribological behavior of (30% volume
fraction) glass-polyester composite system. The stress-strain relations, modulus of
elasticity, yield stress, ultimate tensile strength and ultimate compression strength were
studied according to ASTM-D 638-87and ASTM-D 695 to present the composite
mechanical behavior. The wear rate and wear resistance were investigated according to
ASTM-D 5963 using pin on disc machine to present the composite tribological behavior.
The results showed that the mechanical and tribological properties behavior was
improved when the graphite filler content was increased up to 7.5% and then decreased
after that. At 7.5% filler content the modulus of elasticity, yield stress, ultimate tensile
strength, ultimate compression strength and wear resistance increased by (41%, 64%,
24%, 60% and 38%) greater than unfilled composite, while the wear rate was decreased
by 27% less than the unfilled one.