Typically in plywood shear failure is the "rolling shear".....

I thinks the best one is failure in wood, not in Glue line.

By Regards

100% wood broken in the right way.

Panel shear is another option depending what you're after and equipment available.

What Shear do you mean? How it related to the fiber position?

Could you referenced the type of structure for which you have shear failure modes?

My advise if to focus on structure type.

From the point of view of statistics, testing specimens of one sample unit as many as possible, at least 30 specimens. Hopefully, you could see the trend of the value.

I invite you to have a look at the below article, I believe that it would have some interesting information about the fracture properties of wood and wood based composites,

Fracture Properties of Wood and Wood Composites

• July 2009
• Advanced Engineering Materials 11(7):600 - 606
• DOI:
• 10.1002/adem.200900048