Load and Stress Analysis

Question 1

__________ come across different materials like
cement, concrete, steel and others which are used
to complete the project

Answer 1

Engineers

Question 2

In selecting suitable material, one is interested to
know its _________.

Answer 2

Strength

Question 3

The ability of element of the structure to resist
failure under application of external forces is
known as “__________” and the ability to
resist deformation is known as “________” of that
material.

Answer 3

strength of material; stiffness

Question 4

It has been observed that the material first _______
and then ________ takes place.

Answer 4

deforms; failure

Question 5

Whenever force acts on body, it undergoes _________ and some resistance to deformation.

Answer 5

deformation

Question 6

When _________ is removed, the resistance to force will vanish and the body came back to its _________.

Answer 6

external force; original shape and size

Question 7

This is possible if deformation due to external force is within certain limit known as “__________”.

Answer 7

Elastic Limit

Question 8

Is the ability of the material to retain its original shape and size perfectly after removal of load.

Answer 8

Elasticity

Question 9

Is the tendency of solid materials to return to their original shape after forces are applied on them.

Answer 9

Elasticity

Question 10

When forces are removed, the object will return to its initial shape and size if the material is _________.

Answer 10

elastic

Question 11

_______________________ (3) are examples of the elastic materials.

Answer 11

Steel cables, rubber bands, springs

Question 12

Is the limit within which the body behaves
perfectly elastic.

Answer 12

Elastic Limit

Question 13

Is the limit within which the body behaves
perfectly elastic.

Answer 13

Elastic Limit

Question 14

Elastic Limit is very ______ for a substance like steel and _____ for a substance like lead.

Answer 14

high; low

Question 15

Resistance per unit deformation is known as ______.

Answer 15

Stress

Question 16

Tensile Stress = _______________
Compressive Stress = __________

Answer 16

Positive; Negative

Question 17

S𝑡𝑟𝑒𝑠𝑠, 𝜎 = 𝐿𝑜𝑎𝑑/𝐴𝑟𝑒𝑎 = 𝑃/𝐴, what is the unit of measurement of stress?

Answer 17

Unit: N/mm^2 or (Pa)scal (Pa, Kpa, Mpa, Gpa)

Question 18

Types of Stress

Answer 18

Normal, Tangential

Question 19

Is a stress that occurs when the surface of
the body is loaded by an axial force.

Where,

S𝑡𝑟𝑒𝑠𝑠, 𝜎 = 𝐿𝑜𝑎𝑑/𝐴𝑟𝑒𝑎 = 𝑃/𝐴

𝜎 – Normal Stress
P – Axial Force
A – Cross Sectional Area

Answer 19

Normal Stress

Question 20

Types of Normal Stress

Answer 20

a. Tensile Stress
b. Compressive Stress

Question 21

Is the stress state leading to expansion: that is, the length of material tends to increase in the tensile direction.

Answer 21

Tensile Stress

Question 22

Normal Stress

___________________

• Consider a vertical rod of uniform cross-sectional area A subjected to equal and opposite pulls F at the ends of the rod.
• These pulls tend to lengthen the rod, which is said to be in tension.
• The rod is in equilibrium under the action of the two external forces.
• Thus, a cross section A of the rod is acted on by a downward force equal to the force F exerted by the part of the rod below it and an upward force equal to the force F exerted by the part of the rod above it.

Answer 22

Tensile Stress

Question 23

Tensile Stress
* The tensile stress at that cross section in the rod is
defined as
𝜎𝑡 = 𝐹/𝐴

Where:
𝜎t - tensile stress in lb/in2 (psi) or N/mm2 (Pa)scal
F - external tensile force (or applied load) in lbs or N
A - stressed cross-sectional area in in2 or mm2
.

Answer 23

Tensile Stress

Question 24

A tensile stress is also called a normal stress because the external and internal forces are __________ (normal) to the cross-sectional area under consideration.

Answer 24

perpendicular

Question 25

Tensile Stress

Sample Problem:
Find the stress of the 50 mm diameter rod under tension with an applied force of 200KN.

Answer 25

𝜎𝑡 = 𝐹/𝐴 = 200/𝜋[(100𝑚𝑚^2)/4] =
= 101.91 Pa

Question 26

_____________ Is a solid material’s ability to
deform under tensile stress

Answer 26

Ductility

Question 27

A force that attempts to squeeze or compress a material.

Answer 27

Compressive Stress

Question 28

UTM means?

Answer 28

Universal Testing Machine

Question 29

• Consider a vertical rod of uniform cross-sectional area A subjected to equal and opposite pushes F at the
  ends of the rod.
• These pushes tend to shorten the rod, which is said to be in compression.

Answer 29

Compressive Stress

Question 30

The ______________ in the rod is
𝜎𝑐 = 𝐹/𝐴

Where:
𝜎c - compressive stressin lb/in2 (psi) or N/mm2 (Pa)scal
F - external compressive force (or applied load) in lbs or N
A - stressed cross-sectional area in in2 or mm2
.

Answer 30

compressive stress

Question 31

Compressive Stress
Sample Problem:

Calculate the compressive strength of a concrete cylinder. The cross-sectional faces of the cylinder each measure 6 inches across, and the cylinder failed at 71,000 pounds of force. What is the compressive strength of that sample of concrete?

Answer 31

Solution:
𝜎𝑐 = 𝐹/𝐴 = 71000 𝑙𝑏𝑠 / 𝜋(3𝑖𝑛𝑐ℎ𝑒𝑠)^2

= 71000 𝑙𝑏𝑠/28.26 𝑖𝑛𝑐ℎ^2

= 2512 psi

Question 32

A compressive stress is also called a normal stress because the external and internal forces are ________ to the cross-sectional area under consideration.

Answer 32

normal

Question 33

• Consider a rectangular solid subjected to a
  force F acting to the right along its top surface and
  an equal and opposite force F acting to the left
  along its bottom surface.
• Also imagine that the solid consists of layers, each
  of area A, parallel to the top and bottom surfaces.
• Each layer is acted on by two forces.
• The layer above it exerts a force F to the right, and
  the layer below it exerts a force F to the left.
• These forces tend to cause one layer to slide, or
  finally shear off, with respect to another layer.

Answer 33

Shearing Stress