Uneven Tear Strength
Uneven tear strength refers to the maximum load that a bonded joint can withstand when subjected to uneven tearing forces. Since the load is concentrated on two edges or one edge of the adhesive layer, the stress is calculated per unit length rather than per unit area, with the unit being kN/m².
Impact Strength
Impact strength denotes the maximum work consumed per unit adhesive area when a bonded component fails under impact loading, measured in kJ/m². The impact strength is influenced by factors such as the toughness of the adhesive, adhesive layer thickness, type of adherend, specimen size, impact angle, environmental humidity, and test temperature. Generally, adhesives with better toughness exhibit higher impact strength.
Endurance Strength
Endurance strength is the maximum load that a bonded joint can withstand per unit adhesive area after long-term exposure to static loading, expressed in megapascals (MPa). Endurance strength is affected by applied stress and test temperature— it decreases as both the loading stress and temperature increase.
Fatigue Strength
Fatigue strength refers to the maximum stress that a bonded joint can repeatedly withstand for a specified number of cycles without failure. The fatigue strength at 10 cycles is commonly referred to as the fatigue strength limit. In general, adhesives with high shear strength tend to have lower peel, bending, and impact strengths, while adhesives with high peel strength exhibit higher impact and bending strengths. Various types of adhesives also show significant differences in their strength characteristics.
