B Yield Point vs Elastic Limit

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1. Nov 12, 2017

Abu

I don't understand the difference between the elastic limit and the yield point. I understand that if you stretch a material within the elastic limit, then the material should return to its normal shape. However, the yield point is described as the point at which a permanent increase in length is obtained. So shouldn't the elastic limit and the yield point be the same point on a force by length graph? In the graph the yield point is further past the elastic limit.

Thank you.

2. Nov 13, 2017

DoItForYourself

You are right.

Generally, elastic limit is an alternative name for yield point (or yield stress). The distinction of the two points seems weird.

3. Nov 13, 2017

JRMichler

Since the elastic limit is difficult to find exactly, the yield point is usually defined as 0.2% yield. That's a lot easier to measure, and thus more reproducible.