Glass is difficult to grip so glass strength is measured in flexure or bending. Modulus of rupture, or MOR, is normally associated with glass strength and calculated to be the is maximum surface stress in a flexed beam at point of failure. In tensile tests, all flaws see the maximum stress so MOR or modulus of rupture is larger by 30% because the volume subjected to maximum stress is small, and the probability of a large flaw in the highly stressed region is also small. Glass strength testers are set up to test brittle materials.
The most common test standard, or testing method or norma for glass strength is ASTM C158 which calculates modulus of rupture. Testing for glass strength and modulus of rupture typically involves using a large surface area and precluding edge effects which C158 attempts to do. ASTM C158 uses flexure strength to calculate modulus of Rupture of glass as it minimizes breaks that originate at the edge. Other glass strength tests minimize edge effects by testing for equibiaxial strength such as ASTM F394 or ASTM C1499. Non-strengthened glass materials have relatively low tensile strength yet high compressive strength, and so most glass breakage is due to tensile stress failure. The most common glass strengthtesting standards for glass is ASTM C 158. It measures modulus of rupture and recommends that the ratio of the width to thickness of standard MOR specimens be between 2:1 and 10:1. Glass Strength Testing Equipment Our G22 or G238 Series MOR modulus of rupture flexural bend fixtures, both feature load span and support span anvil and rollers designed to rock parallel and normal to the long axis of specimen. This allows adjustment to make good contact in imperfect specimens that can be tapered either along the length or across the height. Testresources offers a line of building Glass Strength Bend Testing Equipment , Testers and Test Machines with modular fixtures that can be configured to specific glass strength bend testing needs. They can be configured with safety enclosures to handle the sample breakage. Our G124 four point bend fixture is designed specifically to EN 1288 requirements. In general, our MOR modulus of rupture flexural bend fixtures feature load span and support span anvil and rollers designed to rock parallel and normal to the long axis of specimen. This allows adjustment to make good contact in imperfect specimens that can be tapered either along the length or across the height.
Applicable Testing Standards
Recommended Test Machine
Forces up to 10 kN (2,250 lbf)
Low force tabletop systems
Modular series of five frame options with adjustable test space
Affordable testing option for tension, compression, bend, peel and much more
Force range of 5 kN to 600 kN (1,125 lbf to 135,000 lbf)
Adjustable test space
The most popular choice for static tension and compression tests
These dual column testers are available in both tabletop and floor standing models
Recommended Testing Accessories
Designed in accordance to ASTM C158
Designed in accordance to EN 1288
Load ratings up to 250 kN (56,250 lbf)
Base lengths up to 1200 mm (48 in)
Various roller sizes available
Available in 3-point and 4-point configurations
