Volume 4 - Loctite.ph

Joint Stress DistributionJoint stress distribution is the location of stresses within a bond.PEEL STRESS: A peel stress occurs when a flexible substrate is beinglifted or peeled from the other substrate.NOTE: The stress is concentrated at one end.Stress: Usually expressed as Newtons per square meter (N/M 2 ),which is equivalent to a Pascal (Pa.) In the English system, stressis normally expressed in pounds per square inch (psi).Types of StressesThere are several types of stresses commonly found in adhesivebonds which include:• Shear• Tensile• Compressive• Peel• CleavageSHEAR STRESS: A shear stress results intwo surfaces sliding over one another.CLEAVAGE STRESS: A cleavage stress occurs when rigid substratesare being opened at one end.NOTE: The stress is concentrated at one end.TENSION AND COMPRESSION STRESS DISTRIBUTION: When a bondexperiences either a tensile or a compressive stress, the joint stressdistribution is illustrated as a straight line. The stress is evenly distributedacross the entire bond. Tensile stress also tends to elongate an object.78The Loctite ® Design Guide for Bonding Plastics, Volume 4