Digital pure shear-strain moiré patterns.

A method of constructing digital shear-strain moiré patterns with pure shear-strain fringes is proposed here with the help of digital image processing techniques and moiré carrier patterns of rotation. This method is developed from a digital pure secondary moiré pattern method. The pure shear-strain moiré patterns do not require a high fringe density of primary moiré patterns. It can give the shear-strain values at every point over the whole field and give the visible distribution of the shear-strain field.