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Shear strength profiles
Out-of-plane shear properties are often very critical in paperboard. The out-of-plane shear strength is much weaker than the in-plane strength. Shear damage are therefore often causing failure. In the creasing operation paperboard will be loaded in shear, which is utilized to make purpose made damage to improve foldability and package performance.
Purpose
If paperboard is designed in the ZD direction it will be possible to optimize the paperboards performance in different applications. One can position locations in different ZD positions. This can be done by either working with the interfaces or the middle ply. The shear strength profiles can be used to characterize the different paperboards designs.
At RISE we have measured hundreds of shear strength profiles, and we can give you and provide help to optimize industrial processes to design paperboard performance.
Method
Shear strength profiles can be measured in different positions in the through thickness direction (ZD). The double notched shear specimen is used to measure the shear strength. Two notches meet in a certain ZD postion. When the specimen is loaded in tension with force F, the specimen will fail in shear between the notches. Shear strength is calculated as: F^max/Lw
where width w=15 mm and the length L=5 mm. The repeatability of the method if often very good, and there are mostly larges variations within a paperboards than between samples.
Deliveries
Shear strength profiles in the thickness direction.