Mechanics Of Deformable Bodies Flashcards
A force perpendicular to the section is…
Axial
A force parallel to the section is…
Shear
Moment parallel to the cross section…
Bending
Moment perpendicular to the cross section…
Torsion
External forces cause…
Change in the state of motion of a body
An external force is…
A force that develops at the surfaces of contact between bodies
Internal forces cause…
Deformation
What is failure (the engineering kind of failure)?
When an object no longer functions as intended
Failure is dependent on what 2 things?
Applied force and cross sectional area
What is the formula for stress?
Stress = force / area
Definition of stress…
Force acting per unit area.
A material is continuous if…
Uniform distribution of matter; no voids
The material is cohesive if…
All portions are connected together; No breaks, cracks or separations
A homogeneous material has…
Same physical and mechanical properties all throughout
And isotropic material has…
Same properties in all directions
A prismatic object has..
Constant cross-sectional area
Average normal stress is… And it is represented by the Greek letter…
Average normal stress is when the force is acting perpendicular to the cross section. Represented by sigma ( looks like o ).
If the force is parallel to the object the stress is called… And it is represented by the Greek letter…
Average sheer stress… Tau (looks like T)
The unit of stress is called the…
Pascal 1 N/m^2
What are the three design considerations?
Strength, serviceability, economy
What is strength?
The actual load a structure can carry
What is serviceability?
Resistance to vibrations, deformations, deflections, cracks. Overall functionality.
What is economy?
Most efficient and cost-effective design
What Greek letter represents deformation?
Delta (looks like d)
What causes deformation?
When forces are applied or temperature is changed
Define strain.
Normal strain is the change in length. Shear strain is the angular change between two perpendicular segments.
Normal stresses lead to…
Normal strain
Strain is represented by the Greek letter…
Epsilon (looks like a reversed 3)
Normal strain is calculated with the formula…
Strain = deformation/original length (E=d/L)
Is the object gets longer the normal strain is…
Positive