# 4.4.5 Cleavage Stress

> From: LOCTITE®X Digital Manual for Bonding (https://www.loctitex.com/en/manuals/bonding/4.4.5-cleavage-stress/)

#### 4.4.5 Cleavage Stress

Cleavage stress occurs when rigid substrates are opened at one end. Standardised tests to simulate cleavage stresses are done by gripping the ends and pulling apart or by driving a wedge between the substrates through the adhesive layer. This test is particularly important for measuring properties related to crack propagation in adhesives.

_Figure 99 Cleavage stress distribution on a bonded assembly_

![Figure 99 Cleavage stress distribution on a bonded assembly](/en/manuals/bonding/assets/img/cleavage-stress-distribution-bonded-assembly-1.jpg)

![Figure 99 Cleavage stress distribution on a bonded assembly](/en/manuals/bonding/assets/img/cleavage-stress-distribution-bonded-assembly-2.jpg)