In which region of a stress strain graph does necking occur?

The third stage is the necking region. Beyond tensile strength, a neck forms where the local cross-sectional area becomes significantly smaller than the average. The necking deformation is heterogeneous and will reinforce itself as the stress concentrates more at small section.

What does a straight line on a stress strain graph mean?

The straight-line implies that stress and strain share a linear or direct relationship throughout OA. Or, simply, the material obeys Hooke’s law. The proportionality can be removed by equating them with a constant, in this case, Young’s modulus or the modulus of elasticity of the material.

Is it possible to have strain when stress is zero?

Strain is zero but stress is present= consider bar fixed at two ends and there is NO yielding/movement in supports. now when temperature is increased the bar will experience thermal stresses as there is resistance to axial expansion. but strain will be zero as change in length in axial direction is zero.

Where in the stress strain curve is valid?

True stress-strain curves obtained from tensile bars are valid only through uniform elongation due to the effects of necking and the associated strain state on the calculations.

Where is the necking region where is the necking region where is the necking region?

Necking, in engineering or materials science, is a mode of tensile deformation where relatively large amounts of strain localize disproportionately in a small region of the material. The resulting prominent decrease in local cross-sectional area provides the basis for the name “neck”.

Where is the necking region occurs?

A necking region at the edge of a crack in a sufficiently thin sheet, grows continually under loading until complete sliding off occurs.

How do you read a stress-strain graph?

The stress-strain relationship is displayed on an x-y graph, where the y axis (vertical axis) represents stress, and the x axis (horizontal axis) represents strain (as seen in Figure 2). Therefore the stress-strain slope (change in y over change in x) is Stress divided by Strain.

Should the stress-strain graph for rubber be a straight line?

Stress – strain graph beyond elastic behaviour In the elastic region the stress-strain graph is a straight line. The graph, then becomes non-linear because Hooke’s law is not obeyed and stress is not proportional to strain.

How does a stress-strain curve work?

A stress-strain curve is a graphical way to show the reaction of a material when a load is applied. It shows a comparison between stress and strain. Stress is the ratio of the load or force to the cross-sectional area of the material to which the load is applied.

Why does the stress-strain graph start to curve?

As a result, the graph starts to curve. The molecular structure of each material determines its response to increasing stress, Hence depending on the material under test, the stress-strain graph will go through various phases. Finally, the stress will be too high, and the material will fracture.

What is the relationship between stress and strain?

As the stress increases, the strain caused by it varies according to the properties of a material. The relationship can be limned by a graph, and this graph is referred to as the stress-strain curve, where stress is plotted on the Y-axis and strain is plotted on the X-axis.

What is the stress-strain diagram for different materials?

The stress-strain diagram for different material is different. It may vary due to the temperature and loading condition of the material. A tensile test is done on the material for drawing the stress strain curve.

How does the stress-strain relationship deviate from Hooke’s law?

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. This is the part of the graph where the first curve starts but has not yet taken a turn downwards.