4.materials Flashcards
Archimedes principal
The upthrust exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces
What allows material to only obey hook law
If it has not passed, what is called the limit of proportionality
What will happen to the work done in deforming material sample before it reaches its elastic limit?
Stored in material as elastic strain energy
Hooks law formula
For supplied = stiffness constant x extension
What is tensile (compressive) stress formula
F/A
Reduces the thickness
What is tensile or compressor strain?
Extension /original length
Eliminates length of an object
Young modulus
Stress/strain
Material property
Describes how easily something will stretch .
Measure of stiffness
What does the term elastic mean?
Object forms when forces applied and returned to its original shape when the force is removed
What does the term plastic mean?
Object that deforms when it forces applied, but fails to return to its original shape when the forces removed
What what is the name from origin to point a on a stress strain graph?
Limit of proportionality which obeys hooks law after this, the material deforming away, but the changes of structure and material will be plastic
What is point B and onwards on an elastic strain graph
Yield point whether is a sudden increase in extension metal ion layers slip to reduce internal stress
What is point C and beyond on a stress strain graph
Stress decreases as strain increases
What is point D and beyond
Ultimate tensile stress, UTS, which is the highest value of stress the material can experience and the material will inevitably fail beyond this stress
What is point E a.k.a. the final point on a stress strain graph
Fracture stress, which is a point of failure where material will break and structure cannot withstand the stress
What is Stokes law formula?
F=6x pi x r x viscosity co x velocity
