Membrane materials critical stress

The unit of toughness is a very important parameter used in fracture mechanics. Toughness, K, is the property of a material to absorb energy, hi the U.S. Customary system, this unit is expressed as ksiVin. When using the metric SI system, many people use MPa An, mainly because it is closer in value to the U.S. Customary unit. The m denotes meters. The critical value of the mode stress intensity, Kj, at which fracture occurs is a function of the maximum uniform membrane stress. In the SI system, stress is usually denoted as MPa (N/mm ). Since the stress unit MPa is 1.0 N/mm, the unit for toughness becomes... 

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