ENGMECH Quiz 3 Flashcards
Branch of Engineering Mechanics which deals with the study of the external and internal effects of forces and environmental factors on deformable bodies.
Mechanics of Deformable Bodies
The condition under which stress is constant or uniform throughout the surface of a body
Simple Stress or Uniform Stress
A load that is directed along the longitudinal axis of the member.
Axial Force
The condition under which stress is constant or uniform throughout the surface of a body.
Simple Stress or Uniform Stress
Axial forces that tend to elongate a member
Tension Force
Axial forces that tend to shorten a member
Compression Force
The unit “MPa” is equivalent to ________
Newtons/ mm^2
The unit “Pa” is equivalent to ________.
Newtons/ m^2
The intensity of an internal force, but acts on a surface that is parallel to the internal force.
Shear Stress
If two bodies are pressed against each other, compressive forces are developed on the area of contact. The pressure caused by these surface loads is called _______ .
Bearing Stress
1 kip = _____ lbs
1000
A geometric quantity that measures the deformation of a body
Strain
Change in the body’s shape and size whenever a force is applied to the body. May also occur when the temperature of the body is changed.
Deformation
Type of strain which characterizes dimensional changes
Normal Strain
Type of strain which describes distortion (changes in angles)
Shear Strain
Formula for Normal Strain
Epsilon = change in L /L
The main output from the tensile test is the _____ .
Stress-Strain Graph
Formulas for Deformation
Delta = Lf-Lo (Final- Initial Length)
Delta = PL/AE = (Stress x L)/ E
Formulas for Stress
Stress = P/A
In the formula given by Delta = PL/AE, what are the three restrictions on the use of this equation?
- Load must be axial
- The bar must have a constant cross section and homogenous
- The stress must not exceed the proportional limit
Differentiate Deformation and Deflection
Deformation = Change in length
Deflection = Change in position
Formula for Bearing Stress
Sigma b = Pb / Ab = P / td
Formula for Poisson’s Ratio
v = - Epsilon (lat or trans) / Epsilon (long)
Epsilon (trans) = Change in diameter / diameter
Epsilon (long) = Deformation / Length
Formula for Hooke’s Law
Stress = E (Young’s Modulus) x Epsilon (Normal or Longitudinal Strain)
Formula for Shear Stress
Tau = V / A = P / nDt
