# Shared Flashcard Set

## Details

Structures II Test 1 Short Answer
Structures II Test 1 Short Answer Questions
19
Aerospace Engineering
02/14/2011

Term
 Failure envelopes are always plotted in terms of which stresses?
Definition
 Principle Stresses
Term
 What is the other name for the maximum shear stress criterion?
Definition
 Tresca Criterion
Term
 What is the other name for the maximum distortion energy criterion?
Definition
 Von Mises Stress Criterion
Term
 A failure envelope for a material is drawn below. Sketch the definition of the factor of safety for the load case at point A. Has the material failed? [image]
Definition
 [image]
Term
 The maximum normal stress criterion includes interactions between stress components. (True or False)
Definition
 False
Term
 The maximum shear stress criterion includes interactions between stress components. (True or False)
Definition
 True
Term
 The maximum distortion energy criterion includes interactions between stress components. (True or False)
Definition
 True
Term
 The Tresca criterion is always more conservative than the Von-Misses stress criterion. (True or False)
Definition
 True
Term
 Which criterion works better for ductile materials: maximum distortion energy or maximum normal stress?
Definition
 Maximum Distortion Energy
Term
 What is a S-N diagram?
Definition
 representation of the relationship of stress S and the number of cycles N before failure of the material.
Term
 What is an endurance limit?
Definition
 A stress amplitude below which a material will not fail no matter the number of cycles.
Term
 Give 3 environmental factors that can decrease the fatigue life of a component.
Definition
 Fretting , corrosion, and stress concentrations
Term
 Define a composite material.
Definition
 Material composed of two or more constituents (heterogeneous)
Term
 List 2 advantages of composite materials.
Definition
 Light weight; resistant to corrosion
Term
 What are the 4 essential steps in the fabrication of a composite structure?
Definition
 Layup; infiltration; heat transfer; and curing
Term
 What is a pre-preg?
Definition
 Pre-preg is a tape or sheet of fibers impregnated with resin (partially cured)
Term
 How many independent material properties does an orthotropic material have?
Definition
 Nine
Term
 How many independent material properties does an orthotropic material have assuming a state of plane stress? List them.
Definition
 Four: E1; E2; ν12; G12
Term
 What is the physical meaning of η­­sx or ηxy?
Definition
 ηsx -- Characterizes the strain in the x direction caused by the shear stress in the x-y plane. ηsy – Characterizes the strain in the y direction caused by the shear stress in the x-y plane.
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