The following material properties are required:
- Ultimate Tensile Strength – The strength at which the material experience overstress failure.
- Yield Tensile Strength – The strength at which the material transitions from elastic to plastic and permanently deforms.
- Modulus of Elasticity – This is the slope value of the elastic portion of the stress/strain curve.
- Ultimate Strain – This is the strain of the material at ultimate tensile failure. This value can be found in material property texts such as MIL-HNBK-5 or MMPDS.
AFFDL-TR-69-42 suggests using cross grain failure properties only for bearing and transverse lug allowables but it is common practice to use the same failure properties (either cross grain or longitudinal) for all lug allowables, to include net tensile section allowables. If it is desirable to build conservatism into the lug analysis or lug grain orientation is unknown, it is recommended that cross grain failure properties be used. If the grain structure of the lug is known, it is recommend the engineer select the material property that represents the actual lug.