How do you interpret stress strain curves?

If the load is below the yield point on the stress-strain curve, then the material will return to its original shape after the load is removed. This means that the material is elastic. If the load is large enough to be above the yield point, the material will permanently deform and elongate.

How do you compare stress and strain?

Stress causes strain, strain results in structures

• Stress is a force acting on a rock per unit area.
• Strain is a change in shape or size resulting from applied forces (deformation).
• Structures in geology are deformation features that result from permanent (brittle or ductile) strain.

How do you identify a material from a stress-strain curve?

A material’s Stress/Strain Curve is typically determined by testing a ‘dog-bone’ specimen of the material (as seen in Figure 3) of the material in question with a Tensile Strength Testing Machine, or TSTM.

How do you compare Young’s modulus from a stress strain graph?

Young’s modulus of elasticity (E), also known as the elastic modulus, is the ratio between stress and strain: E = s /e , and has the same units as stress. E is the slope of the stress-strain graph: the steeper the slope, the stiffer the material.

How do you determine the ultimate strength of a stress strain curve?

From this curve we can determine: a) the tensile strength, also known as the ultimate tensile strength, the load at failure divided by the original cross sectional area where the ultimate tensile strength (U.T.S.), σ max = P max /A 0 , where P max = maximum load, A 0 = original cross sectional area.

What is elastomers explain with stress strain curve?

An elastomer is a polymer with viscoelasticity (having both viscosity and elasticity) and very weak inter-molecular forces, generally having low Young’s modulus and high failure strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber.

How do you differentiate tensile stress from compressive stress?

Tensile stress is the normal force per area (σ = F/A) that causes an object to increase in length. Compressive stress is the normal force per area (σ = F/A) that causes an object to decrease in length.

How does stress differ from strain quizlet?

Stress is the force applied. Strain is the result(change in the shape of the rock).

How is ductility measured in a stress strain curve?

Ductility is a measure of materials ability to deform before failure. Ductility can be quantified by reading the value of strain at the fracture point on the stress strain curve or by doing a percent reduction in area calculation.

How do you determine the toughness of a stress strain curve?

Therefore, one way to measure toughness is by calculating the area under the stress strain curve from a tensile test. This value is simply called “material toughness” and it has units of energy per volume. Material toughness equates to a slow absorption of energy by the material.

How do you find the shear modulus from a stress strain curve?

Modulus is defined as being the slope of the straight-line portion of a stress (σ) strain (ε) curve. Focusing on the elastic region, if the slope is taken between two stress-strain points, the modulus is the change in stress divided by the change in strain.

What is Young’s modulus measured in?

The units of Young’s modulus in the English system are pounds per square inch (psi), and in the metric system newtons per square metre (N/m2).

What is the relationship between stress and strain in a test piece?

As the test piece is subjected to increasing amounts of tensile force, stresses increase beyond the proportional limit. The stress-strain relationship deviates from Hooke’s law. The strain increases at a faster rate than stress which manifests itself as a mild flattening of the curve in the stress and strain graph.

Why is the stress-strain curve important in Mechanical Engineering?

The stress-strain curve provides design engineers with a long list of important parameters needed for application design. A stress-strain graph gives us many mechanical properties such as strength, toughness, elasticity, yield point, strain energy, resilience, and elongation during load. It also helps in fabrication.

What is the formula for calculating strain?

The formula for calculating strain is: ε= (l-l 0)/l 0, where l 0 is starting or initial length (mm) l is stretched length (mm)

What is the yield strength point on the stress-strain graph?

This aligns with the start of the strain hardening region in the stress-strain graph. The yield strength point is where the plastic deformation of the material is first observed. If the material is unclamped from the testing machine beyond this point, it will not return to its original length.