mock exam

Question 1

what is a moment

Answer 1

for a moment to develop a force must act upon a body in such a manner that is starts to bend or rotate

Question 2

explain equilibrium

Answer 2

a structure is equilibrium when all forces or moments acting upon is balanced.
each force acting upon a body or part of a body is resisted by either another equal and opposite force or set forces
whose net result is zero

Question 3

describe laminar tearing causes an preventions

Answer 3

occurs beneath the weld especially in rolled steel plates which have poor though- thickness ductility an can have potentially life-threating results
causes:
high residual stresses in material
incorrect joint design
preventions:
change joint design
use buttering layers

Question 4

what is a heat exchanger

Answer 4

a heat exchanger is a system used to transfer heat between a source and a working fluid

heat exchangers are used in both cooling and heating processes

Question 5

list 5 factors which influence design?

Answer 5

design
materials
fabrication
inspection
operation
repair
maintance cost

Question 6

what is comprehensive load

Answer 6

CL is a Push force
CL may require to prevent buckling

Question 7

how do you calculate elongation

Answer 7

final Length - original length over original length X 100

Question 8

what is proof stress

Answer 8

PS is a term used to describe the stress that will cause a specified small permanent, extension of a tensile test piece,
typically, a limit would be defined at 0.1 % or 0.2% and the concept is called proof stress

Question 9

what is brittle fracture?

Answer 9

it gives little to no warning signs
it appearance is smooth
it shape is chevron shape
it happens under low temp
it happens without significant deformation

Question 10

explain ductile fracture

Answer 10

it gives l more warning signs
it appearance is rough
it shape is cup cone
it happens under high temp
it happens with significant deformation

Question 11

explain fatigue failure

Answer 11

it occurs at a stress point, eg a defect or toe of a fillet weld
it has beach marks on the surface of the fracture
i

Question 12

explain the phenomenon creep?

Answer 12

creep is a failure mechanism
failure to cracking of fracture can iccure in materials that operate at high temp for extensive periods of litme
it occurs in 3 phases
primary
secondary
tertiary

Question 13

types of SMAW electrodes

Answer 13

0,1 =cellulose
2,3,4 = rutile
5,6,8 basic or LH