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Material Properties
2142-391 Engineering Mechanical LaboratoryAUTOMOTIVE DESIGN AND MANUFACTURING
International Program, Chulalongkorn University
Brackgrounds
Challenger was destroyed in the second minute of STS-51-L, the orbiter's tenth mission, on January 28, 1986, when an O-ring seal on its right solid rocket booster (SRB) failed. The O-rings failed to seal due to a variety factors, including unusually cold temperatures. This failure allowed a plume of flame to leak out of the SRB and impinge on both the external fuel tank (ET) and SRB aft attachment strut. This caused both structural failure of the ET, and the SRB pivoted into the orbiter and ET. The vehicle assembly then broke up under aerodynamic loads.
Mathematical Models
EA
FLDeformation of Axially-Loaded Member
GJ
TLDeformation of Torsion Member
Deflection of Beam MEI
2
2
eCR L
EIF
Buckling
. . Y
allowable
S F
Safety Factor
Objectives
To study how to test the materials for obtaining the desired properties. Tensile test Hardness test Impact test
To study how to evaluate the mechanical properties of the materials.
Etc. ( Options) Can we relate the material properties to applications? Can we determine the tensile strength from the hardness value? Can we explain the fracture mechanism of ductile and brittle materials? etc.
Data Reduction (Tensile Test)
Young’s Modulus
0.2% offset Yield Stress
Tensile Strength
% Elongation
% Reduction of Area
Modulus of Resilience
Modulus of toughness
Etc.