Mackerel patterns

Murray, J. and Hull, D. (1970) Fracture surface of polystyrene mackerel pattern, J. Polymer Sci., Polymer Phys., 8, 583-594. 

Lamellae deformation Lamellar separation Mackerel pattern... 

Mackerel pattern Fracture surface pattern similar to that on the back of a mackerel fish 1.30, 1.64... 

The crack frequently initiates from the breakdown of a craze that formed at an internal defect, as a void or impurity particle. Then, as shown by various investigators, as crack speed increases, the crack jumps rapidly from one craze bulk interface to another and from one craze to another. This can lead to a so-called mackerel type pattern on the fracture surface or to a craze island type structure see also Chapter 1 and 3. As crack length increases and local stress rises, numerous secondary fractures, as shown in Fig. 2 b, are generated ahead of the crack front. 

The Atlantic mackerel can be distinguished from other species of mackerels by the pattern of up to 24 wavy black lines along the sides of its body above the... 

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