Evaluate elongation of wire, Mechanical Engineering

Evaluate Elongation of wire:

An aerial copper wire (E =1 x 105 N/mm2) 40 m long is having cross sectional area of 80 mm2 and weighs 0.6 N per meter run. If wire is suspended vertically, calculate

(a) Elongation of wire because of self weight,

(b) Total elongation when a weight of 200 N is attached to the lower end of it, and

(c) Maximum weight which this wire can support at the lower end if limiting value of stress is 65 N/mm2.

Sol.:  (a) Weight of wire W = 0.6 × 40 = 24 N The elongation because of self weight is,

δL =   L2/2 E; where ω  is the specific weight (weight per unit volume)

In the terms of total weight W =       ωAL

δL = WL2/E = 24 × (40 × 103)/2 × 80 × (1 × 105)

= 0.06 mm                                                                               .......ANS

(b) Extension because of weight P attached at lower end,

δL = PL/2E

= 200 × (40 × 103)/80 × (1 × 105)

= 1.0 mm

Total elongation of wire = 0.06 + 1.0 = 1.06 mm

(c) Maximum limiting stress = 65 N/ mm2

Stress because of self weight equals that produced by a load of half its weight applied at the end. That is

Stress because of self weight = (W/2)/A = (24/2)/80 = 0.15 N/ mm2

Remaining stress = 65 - 0.15 = 64.85 N/mm2

Maximum weight that the wire can support = 64.85 × 80 = 5188 N

Posted Date: 10/23/2012 1:25:59 AM | Location : United States







Related Discussions:- Evaluate elongation of wire, Assignment Help, Ask Question on Evaluate elongation of wire, Get Answer, Expert's Help, Evaluate elongation of wire Discussions

Write discussion on Evaluate elongation of wire
Your posts are moderated
Related Questions

Type of strain: There are basically four type of strain 1. Tensile strain 2. Compressive strain 3. Volumetric strain 4. Shear strain


Applications of seam welding Lap seam welding is used for the manufacture of cans, buckets and water tanks and for welding thin walled large diameter pipes. Mash seam welding

In a double acting vertical steam engine running at speed of 360 r.p.m., cylinder diameter is 25 cm, stroke is 30 cm, diameter of piston rod is about 3.75 cm and length of the conn

Clutch: Clutch is a part which is used to transmit the rotary motion of one shaft to another shaft, when desired; the axis of second shaft must be in line with the axis of the fir

What is tracing error? Define how to track tracing error?

Duty cycle The concept of duty cycle is to be clearly understood before operating any machine. Unlike the arc welding power sources, the resistance welding power sources are de

A Wilson-Hartnell governor is illustrated in given Figure. In this, the balls are associated by two springs that are known as main springs. The main springs are symmetrically arran

Calculate stress to cause failure - Creep Parameters: From creep tests on 713 C alloy the constant C in Larson-Miller parameter is determined as - 85.75. In rupture test a spe