1. The tensile stress adjacent to hole will be ____________
a) about five times the average stress on the net area
b) about half the average stress on the net area
c) equal to average stress on the net area
d) about two to three times the average stress on the net area
Explanation: From the theory of elasticity, the tensile stress adjacent to hole will be about two to three times the average stress on the net area, depending upon the ratio of diameter of hole to the width of plate normal to direction of stress.
2. What is stress concentration factor?
a) ratio of average stress to maximum elastic stress
b) product of average stress and maximum elastic stress
c) ratio of maximum elastic stress to average stress
d) twice the average stress
Explanation: The ratio of maximum elastic stress to average stress (fmax/favg)is called as stress concentration factor. It becomes very significant when repeated applications of load may lead to fatigue failure or where there is possibility of brittle fracture of tension member under dynamic load. It may minimised by providing suitable joint and member details.
3. What is block shear failure?
a) failure of fasteners occurs along path involving tension on one plane and shear on perpendicular plane along fasteners
b) failure of member occurs along path involving tension on one plane and shear on perpendicular plane along fasteners
c) failure of member occurs along path involving tension on one plane and shear on parallel plane along fasteners
d) failure of fasteners occurs along path involving tension on one plane and shear on parallel plane along fasteners
Explanation: Failure of member occurs along path that involves (i) tension on one plane and (ii) shear on perpendicular plane along fasteners in block shear failure mode.
4. The possibility of block shear failure increases by
a) larger connection length
b) increasing the number of bolts per connection
c) with use of low strength bolts
d) with use of high bearing strength material
Explanation: The block shear failure becomes a possible mode of failure when material bearing strength and bolt shear strength are higher. When high bearing strength of material and high strength bolts are used, only few bolts are required in connection. Decreasing number of bolts per connection results in smaller connection length, but the possibility of block shear failure increases.
5. Which of the following statement is correct?
a) stress and strain calculated using initial cross section area and initial gauge length are referred to as true stress and true strain
b) stress and strain calculated using current cross section area and initial gauge length are referred to as true stress and engineering strain
c) stress and strain calculated using initial cross section area and initial gauge length are referred to as engineering stress and engineering strain
d) stress and strain calculated using current cross section area and gauge length are referred to as engineering stress and engineering strain
Explanation: Stress and strain calculated using initial cross section area and initial gauge length are referred to as engineering stress and engineering strain. Stress and strain calculated using current cross section area and gauge length are referred to as true stress and true strain
6. Arrange the regions of engineering stress-strain curve in order from right to left as in graph
a) strain softening region, strain hardening region, yield plateau, linear elastic region
b) strain hardening region, strain softening region, linear elastic region, yield plateau
c) strain softening region, yield plateau, linear elastic region, strain hardening region
d) strain hardening region, linear elastic region, yield plateau, strain softening region
Explanation: The engineering stress-strain curve is typically represented by four regions : linear elastic region, yield plateau, strain hardening region, strain softening (unloading)region.
7. Which of the following is true regarding engineering stress-strain curve?
a) it gives true indication of deformation characteristics of metal because it is entirely based on true dimensions of specimen
b) it does not gives true indication of deformation characteristics of metal because it is entirely based on true dimensions of specimen
c) it gives true indication of deformation characteristics of metal because it is not entirely based on true dimensions of specimen
d) it does not gives true indication of deformation characteristics of metal because it is not entirely based on true dimensions of specimen
Explanation: The engineering stress-strain curve does not provide true indication of deformation characteristics of metal. It is entirely based on true dimensions of specimen and these dimensions change continuously as the load increases.
8. Choose the correct option
a) post ultimate strain softening in engineering stress strain curve is present in true stress strain curve
b) post ultimate strain softening in true stress strain curve is absent in engineering stress strain curve
c) post ultimate strain softening in true stress strain curve is present
d) post ultimate strain softening in engineering stress strain curve is absent in true stress strain curve
Explanation: The post ultimate strain softening in engineering stress strain curve caused by necking of cross section is absent in true stress strain curve as engineering stress strain curve are based on true dimensions of specimen and true stress strain curve are based on actual cross sectional area of specimen
9.What is the yield point for high strength steel?
a) 0.5% of offset load
b) 0.2% of offset load
c) 0.1% of offset load
d) 1.5% of offset load
Explanation: High-strength steel tension members do not exhibit well defined yield point and yield plateau. Hence, 0.2% of offset load is usually taken as yield point for such high strength steel.
10. True stress strain curve is also known as
a) flow curve
b) un-flow curve
c) elastic curve
d) parabolic curve
Explanation: True stress strain curve is also known as flow curve since it represents basic plastic flow characteristics if the material. Any point on the flow curve can be considered as local stress for metal strained in tension by magnitude shown on the curve.