Nondestructive testing and defect detection using optical techniques has been extensively investigated. This communication presents a simple method for defect detection in deformed circular plates using moiré deflectometry. The experimental arrangement is simple, inexpensive and does not require elaborate vibration isolation requirements.

The question motivating the present study is whether metal sandwich plates with su3ciently strong cores are able to sustain substantially larger blast loads than monolithic solid plates of the same material and total mass. Circular plates clamped at their edges are considered under blast loads large enough to produce substantial de5ections. The material is elastic–perfectly plastic. Material st...

The results from Floquet stability analysis of the flow around nominally two-dimensional long plates with elliptical leading edges and blunt trailing edges are presented, elucidating the early stages of wake transition to turbulent flow. Three modes of instability are found: Mode A, Mode B and a period doubling mode. The first two of these also occur in wake transition for circular cylinders an...

Vibration frequencies and modes for the thickness-shear vibrations of infinite partially-electroded circular AT-cut quartz plates are obtained by solving the two-dimensional (2D) scalar differential equation derived by Tiersten and Smythe. The Mathieu and modified Mathieu equations are derived from the governing equation using the coordinate transform and the collocation method is used to deal ...

SUNITA SINGH, m.b., b.s. (Punjab) From the Brigade Laboratory, Allahabad Instead of the ordinary rectangular rack, a circular rotary rack has been used by us. The experimental tubes are rotated alongside the control tubes. The light comes from below after being reflected from a black surface. The readings are very clear and can be quickly made without disturbing the tubes. The rack consists of ...