interview questions
DESCRIPTION
InterviewTRANSCRIPT
INTERVIEW QUESTIONS
BENDING EQUATION
M/I = f/y = E/R
M Bending Moment Kg-mmI Moment of Inertial about
Centroidal Axismm4
F Internal Resistance Stress Kg/mm2
Y Distance of the fiber from neutral axis
mm
E Young’s Modulus/Elastic Modulus
Kg/mm2
R Radius of Curvature mm
Where
TORSION EQUATION
T/J = Gθ/L = τ/R
T Torsional Moment Kg-mm
J Polar Moment of Inertia Mm4
G Modulus of Rigidity Kg/mm2
θ Angle of Twist Radians
L Length of the Shaft Mm
τ Shear Stress in the element Kg/mm2
R Distance of the element from the centre of the shaft
mm
DIFFERENCE BETWEEN BOLT AND RIVET
Bolt Rivet
It is temporary fastener It is permanent fastener
It is basically meant for taking tension loads
It is basically meant for taking shear loads
WHERE BOLT IS USED
•Bolted Joints are used where applied loading is high.•where the joint must be capable of being disassembled.
WHERE RIVET IS USED
It is used in structure where the structure thickness is up to 2D
WhereD = Rivet Diameter
PARTS OF BOLT
WHAT IS LOAD PATH
It is a path followed from the load application to the supports.
TYPES OF LANDING GEAR
Fixed Landing Gear
Retractable Landing gear
Landing gear is an under carriage of an aircraft.
Tri-Cycle Landing Gear
Tandem Landing Gear
Conventional Landing Gear
LIGHTENING HOLES
As the name it-self says that these are the holes introduced for reducing the weight of the structure in-order not to compromise in the structural integrity.
WHAT IS STIFFNESS
K = F/δ
The Stiffness of a member is defined as the resistance offered against deformation.
WHY BOLTS ARE NOT USED IN AIRCRAFT SKIN
Bolts are not used in aircraft skin because it causes drag when it is flying.
When drag is caused the aircraft consumes more fuel and more thrust required to move forward.
By using the bolt the weight of the structure will increase because if we want to use nut for tightening the bolt.There will be chances of loosening the nut due to the
vibration of the structure.
WHY RIVETS ARE USED IN AIRCRAFT SKIN
Rivets are used in aircraft skin because of the smooth flow of wind when it is flying.
HOW WILL YOU VALIDATE THE RESULT
BY TESTING
FACTOR OF SAFETY
Factor of Safety = Design Ultimate Load / Design Limit Load
Factor of Safety has no limits it’s depend on the designer’s view.Higher the Factor of Safety more safer the structure.
But it is not acceptable in the buyer’s point of view due to weight of the structure.
If the factor of safety is higher then the structure will be heavy.
It measures how safe a Design of a Structure is.
Buildings = 2.0Pressure Vessels = 3.0 – 4.0Automobiles = 3.0Space Vehicles = 1.2 – 2.0
MARGIN OF SAFETY
Margin of Safety = Factor of Safety - 1
Margin of Safety should be in a positive value. If the Margin of Safety is zero then the structure will not take any
additional load. If the Margin of Safety is one then the structure will take one
Additional Load equal to the Maximum Load the structure is designed for.
If the Margin of Safety is in a negative value then the stressed part Of the structure is more like to fail.
Margin of safety is a measure of the excess capacity of the structure regarding Load.