Question

Name: This unusual rock "Howanite is creating problems with the current drill bit. In order to try and correct this problem you send a sample off to Missouri S&T for testing in the rock mechanics lab. The initial results show up as a Stress-Strain diagram on your smart phone (see figure to the left). You need to send off a quick email to the technical support people at the drill bit company regarding the mechanical strength properties of Hoganite. The specific questions you need to answer are listed below. Choose the best answer for each question based upon the graph shown to the left. The Stress scale on the diagram is 5 MPa per interval and the Strain scale on the diagram is 1% per interval Runs A and B were made on different cores taken from the same sample of Hoganite under different experimental conditions Q22) The bit manufacturer requested the Ultimate Strength values for Hoganite based upon the results of Experimental run В) 80 MPa D) 65 MPa B) 35 MPa C) 62 MP A) 30 MPa the race for the two experiments on the same

Answer 1

22. The ultimate strength in a stress-strain curve is the highest amount of stress that a material can withstand before breaking off.

Here in the run B, the maximum stress value before yielding is 35 MPa, which is the ultimate stress for the case.

So option B is correct.