Midterm Concepts Flashcards
The safe twisting moment for a compound shaft is equal to the ______
minimum calculated value
If equal and opposite forces applied to a body tend to elongate it, the stress so produced is called _______
tensile stress
The torsional rigidity of a shaft is expressed by the _______
torque required to produce a twist of one radian per unit length of shaft
The property of a material by virtue of which a body returns to its original shape after removal of the load is called _____
elasticity
The ratio of the ultimate stress to the allowable stress of the material is called _____
factor of safety
If the radius of wire stretched by a load is doubled, then its Young Modulus will be ____
remain unaffected
The total elongation produced in a bar of uniform section hanging vertically downwards due to its own weight is equal to that produced by a weight _____
half the weight of bar applied at lower end
The actual stress that the material has when under load is called _____
working stress
If a material expands freely due to heating, it will develop ______
no stress
The force acting along the circumference will cause stress in the walls in a direction normal to the longitudinal axis of cylinder, this stress is called:
hoop stress
Shearing stress is also known as:
tangential stress
Shear stress induced in a shaft subjected to tension will be:
not uniform
A shearing stress acting on a body changes its:
shape
A cylindrical tank is considered to be thin walled if its diameter is more than _____ times the wall thickness
10
Stress caused by forces acting along or parallel to the area resisting the forces is known as:
shearing stress
A metal wire is stretched along its length. Another identical wire is heated. The resultant length of two wires is the same. What can be said about the diameters of the two wires?
the hot wire has a larger diameter than the stretched wire
A spring is stretched by applying a load to its free end. The strain produced in the spring is:
longitudinal and shear
The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will:
remain same
A physical quantity that has no dimension
strain
If the applied force on the object is such that it tends to decrease the length of an object then it is called:
compressive stress
It is known as the maximum allowable stress that material or object will be subjected to when in service
working stress
In a tensile test, when the material is stressed beyond the elastic limit, the tensile strain ______ as compared to the stress.
increases more quickly
The stress set up in the body, when a deforming force acts tangentially, is known as?
shearing stress
A shaft is said to be in pure torsion if:
two opposite turning moments are applied to the shaft
Which of the following is correct assumption made in the theory of torsion?
the twisting couple acts in the traverse plane only
Unit of Torsional Rigidity
N-mm^2
Pure torsion of a shaft produces:
a longitudinal shear stress and a circumferential shear stress on a surface element of a shaft
In solid shaft, stress at the center is:
zero
A hollow shaft of same cross-section area as solid shaft transmits:
more torque
For a circular shaft undergoing deformation due to a torsional force, what happens to length and radius of the shaft?
remain fixed
The shear stress at the center of a circular shaft under torsion is:
zero
The maximum shear stress occurs on the outermost fibers of a circular shaft under torsion. In a close coiled helical spring, the maximum shear stress occurs on the ______
innermost fibers
If a constant section beam is subjected to uniform bending moment throughout, it bends as -
a circular arc
The total area under the stress-strain curve of a mild steel specimen tested up to failure under tension is a measure of its:
toughness
What is shear modulus?
shear stress/ shear strain
According to Hooke’s law, stress is proportional to:
strain
If a part is constrained to move and heated, it will develop:
compressive stress
A material has identical properties in all directions, it is said to be:
isotropic
In a steam engine, the valve rod is connected by an eccentric rod by means of:
knuckle joint
If the hole’s width decreases in the direction of the load for an elliptical hole in a flat plate, the Stress Concentration Factor will:
increase
______ is defined as the maximum stress to which a material can be subjected without a fatigue failure, regardless the number of cycles
endurance limit
Which is not a method of alleviating stress concentration at the center of a stepped shaft?
providing fastener
What is the value of fatigue notch sensitivity for a fully sensitive material?
1
Stress concentration factor is defined as the ratio of:
maximum stress to the nominal stress
A tension member of diameter d is designed with FOS of 3. If the load and diameter are doubled, FOS will be:
doubled
Stress concentration in static loading having high influence in ______
brittle materials
These are elements that are used as roller in roller bearings:
cylindrical, taper, and spherical
The function of a washer is:
to provide a bearing area
The lateral strain is known as
transverse strain
What are the materials which show direction dependent properties, called?
anisotropic materials
Which type of test on steel is done to obtain the graph of a stress-strain curve?
tensile test
Hooke’s law holds good up to the limit of _______
proportionality
Thermal stress is caused when the temperature of a body:
increase or decrease
If a composite bar of steel and copper is heated, the copper bar will be under:
compression
The ratio of circumferential stress to the longitudinal stress in the walls of a cylindrical shell, due to flowing liquid is:
2
The design of thin cylindrical shells is based on:
hoop stress
For cantilever beam, bending moment will be zero at:
free end
In a beam, effect of bending stress is ______ effect of shear stress
greater than
The load which is distributed uniformly over the length of the beam, then the load is called:
uniformly distributed load
If length of the wire is doubled, then it can hold ________
the same maximum stress as before
According to Hooke’s law, if stress is increased the ratio of stress to strain will ____
remain constant
Young’s modulus is defined as the ratio of:
longitudinal stress and longitudinal strain
Deformation per unit length in the direction of force is known as:
linear strain
The Young’s modulus of a wire is defined as the stress which will increase the length of wire compared to its original length:
same amount
The intensity of stress which causes unit strain is called:
modulus of elasticity
For steel, the ultimate strength in shear as compared to in tension is nearly:
half
The property of a material which allows it to be drawn into a smaller section is called:
ductility
The property of a material by virtue of which it can be beaten or rolled into plates is called:
malleability
In a tensile test, near the elastic limit zone, the ______
tensile strain increases more quickly
The stress necessary to initiate yielding is ______
considerably greater than that necessary to continue it
In a tensile test, the phenomenon of slow extension of the material, i.e. stress increasing with the time at a constant load is called:
creeping
The stress developed in a material at breaking point in extension is called:
breaking stress
Rupture stress is:
load at breaking point
The elasticity of various materials is controlled by its:
stress at elastic limit
The stress at which extension of the material takes place more quickly as compared to the increase in load is called:
yielding point of the material
The stress induced in a body due to suddenly applied load compared to when it is applied gradually is:
two times
The strain energy stored in a body due to suddenly applied load compared to when it is applied gradually is:
four times
In riveted boiler joints, all stresses, shearing, bearing, and tensile are based on the:
size of the drilled or reamed hole
The deformation of a bar under its own weight compared to the deformation of same body subjected to a direct load equal to weight of the body is:
half
Longitudinal stress in a thin cylinder is:
half of the hoop stress
The value of shear stress which is induced in the shaft due to the applied couple varies:
from zero at the center to maximum at the circumference
For normal stress, the constant of proportionality is called:
modulus of elasticity
A bar is said to be of uniform strength when:
the stress at any cross section of the bar is same
What type of stress is produced whenever the applied load cause one section of a body to tend to slide past its adjacent section?
shearing stress
If a uniform bar is supported at one end in a vertical position and loaded by its own weight, the maximum stress occurs at:
supported end
For shear stress, the constant of proportionality is called:
modulus of rigidity
The stress beyond which the material will not return to its original shape when unloaded is called:
elastic limit
A vertically loaded beam, fixed at one end and simply supported at the other is indeterminate to what degree?
first
A material with a high value of modulus of elasticity is:
hard
It describes the length elasticity of the materials
young’s modulus
Who introduced the modulus of elasticity in 1807
thomas Young
The fractional deformation resulting from a stress
strain
As soon as the external forces causing deformation in a perfectly elastic body are withdrawn, the elastic deformation disappears:
completely and instantaneously
If all the dimensions of a vertically suspended circular bar are doubled, then the maximum stress produced in it due to its own weight will:
be doubled
The weight of all non-permanent objects, including people and furniture, in the structure.
live load
The ability of material to absorb a large amount of energy is:
toughness
Stress caused by forces perpendicular to the areas on which they act is called:
normal force
The highest ordinate on the stress-strain curve is:
ultimate strength
It is inert, inactive load, primarily due to the structure’s own weight
dead load
The maximum safe stress a material may carry is called:
allowable stress
The property of metals that allows them to be drawn into wires
malleability
If all the dimensions of a vertically suspended circular bar are doubled and cross sectional area is made half, the maximum change in length due to its own weight will:
be four times
Solids which break above the elastic limit are called:
brittle
The condition under which the stress is constant or uniform is known as:
simple stress
