What is stress and strain in polymer?
Stress-strain curves show the response of a material to an applied (usually tensile) stress. They allow important information such as a material’s elastic modulus and yield stress to be determined. Accurate knowledge of these parameters is paramount in engineering design.
What is the difference between stress and strain?
The basic difference between stress and strain is that stress is the deforming force per unit area, While strain is the apparent change in the shape, volume, or length of an object caused due to stress is called strain.
What is the relation between stress and strain?
Hooke’s law explains the relationship between stress and strain. According to Hooke’s law, the strain in a solid is proportional to the applied stress and this should be within the elastic limit of that solid.
How does strain rate Affect polymers?
Increasing strain rate has the effect of increasing both the modulus and the yield stress and flow stress of a polymer.
What is strain in polymer?
It is caused by orientation and allignment of polymer chains in the direction of the load which increases the strength and stiffness of the plastic in stretch direction and explains the observed increase in (true) stress. The opposite of strain hardening is strain softening.
Does higher strain mean stronger material?
Thus, the yield strength, the ultimate strength and the tensile toughness are all observed to increase with increasing strain rate, which indicates both higher strength and higher toughness under tension at higher strain rates.
What is the difference between stress and strain in elasticity?
When deforming forces act on an object, they can change the object’s shape. The main difference between stress and strain is that stress measures the deforming force per unit area of the object, whereas strain measures the relative change in length caused by a deforming force.
Which comes first stress or strain?
Stress strain curve is a behavior of material when it is subjected to load and frm SN curve we can say stress generates only when there is deformation (or it is about to deform) caused by some mechanical or physical forces. Therefore Strain always comes first then only stress generates.
Do polymers strain harden?
For some polymers, strong stretching with a stress minimum and break at a much higher stress is observed. This phenomenon is known as “strain hardening” and “stress induced crystallization”.
What is strain hardening of polymers?
Strain hardening is observed as a strengthening of a material during large strain deformation. It is caused by large scale orientation of chain molecules and lamellar crystals. This phenomenon is quite often observed when plastic materials are stretched beyond their yield point.
Can there be stress without strain?
Stress can happen with out strain, but strain cannot happen without stress.
Is stress and strength the same?
Stress is a measure of how much force an object experiences per unit area, and strength is a material’s ability to withstand stress.
Does stress exist without strain?
Can there be strain without stress?
Which relieves stress and strain?
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How do polymers fail?
Failure in polymer components can occur at relatively low stress levels, far below the tensile strength because of four major reasons: long term stress or creep rupture, cyclic stresses or fatigue, the presence of structural flaws and stress-cracking agents.
Do polymers strain harden more than metals?
In general, polymers strain harden more than metals.
Do polymers undergo strain hardening?
This phenomenon is quite often observed when plastic materials are stretched beyond their yield point. Polymers that exhibit greater strain hardening are often tougher and undergo ductile rather than brittle failure. The degree of strain hardening depends on both intrinsic and extrinsic factors.
What is the stress/strain behavior of solid polymers?
The Stress/Strain behavior of solid polymers can be categorized into several classes of behavior: 1) Brittle Fracture- characterized by no yield point, a region of Hookean behavior at low strains and failure characterized by chonchoidal lines such as seen in inorganic glasses.
What is the rate of strain and viscosity of polymer?
The polymer liquid resistance is given as “rate of strain” and “viscosity” is the slope of the stress-rate of strain curve. As with solid polymer stress-strain curves, liquid polymer stress-rate of strain curves are temperature dependent, with polymer viscosity decreasing with increasing temperature.
What is the stress-strain relationship for a material?
The stress-strain relationship for a material is given by that material’s stress-strain curve. Under different loads, the stress and corresponding strain values are plotted. An example of a stress-strain curve is given below.
What is the difference between stress and strain in physics?
Main Difference – Stress vs. Strain. When deforming forces act on an object, they can change the object’s shape. The main difference between stress and strain is that stress measures the deforming force per unit area of the object, whereas strain measures the relative change in length caused by a deforming force.