If you apply a tensile force you get a tensile ____ and a tensile _____
And if you apply a compressive force you get a compressive _____ and a compressive _____
Tensile stress/strain
Compressive stress/strain
What is the standard tensile strain test
A rod or wire of a material is clamped in a loading frame
and subjected to a controlled displacement
with a transducer connected to provide an electronic reading of the load corresponding to the displacement
What is Young’s modulus and what does it represent
Young’s modulus is the ratio of stress to strain and
it represents the ‘stiffness’ of a material
What is engineering stress
Engineering stress is the force divided by the ORIGINAL area as this can change
What is true stress
True stress is the stress experienced at the final point before the object begins to deform
What is poissons ratio
The ratio of lateral strains to axial strains
What is shear force
Shear force is the force that acts perpendicular to the member,
can arise from two forces that are not in the same plane e.g. diagonal forces
What is the mechanical definition of strength
The amount of stress a material can take before yield or fracture
What is the mechanical definition of elasticity
The extent to which a material can stretch or compress and still return to its original length
What is the mechanical definition of brittle
A material that once it passes it’s elastic limit will fail quickly or straight away
What is the mechanical definition of ductile
A material that once it passes it’s elastic limit will deform relatively slowly before failure
What is the mechanical definition of hardness
Ability to resist shape change such as scratching
What is the mechanical definition of toughness
Ability to resist impact/energy before failing
What is the mechanical definition of fatigue strength
The ability to endure alternating stresses for a long time
What is elastic limit
The limit of a material after which it will not return to its original shape
What is structural redundancy
The idea that one part of a structure is redundant as long as the rest of the structure is stable
Explain distribution of concrete strength and how the functional strength is chosen
Concrete strengths are distributed normally and the 5% mark is chosen as the functional strength
so that at least 95% of the concrete is strong enough for the function
What is creep
Creep is when a constant stress, sometimes alternating over a long period of time causes deformation.
Creeping is dependant on temperature and stress
What is relaxation
Relaxation is when an element is exposed to a constant strain
and the stress falls away over time from the original
