Instantaneous stress and elongation - bar, Mechanical Engineering

Instantaneous stress and elongation:

What shall be the instantaneous stress & elongation of a 25 mm diameter bar, 2.6 m long, suspended vertically, if any mass of 10 kg falls through a height of 300 mm onto a collar that is rigidly associated to the bottom end of the bar? Take E = 200 GPa.

Solution

We have

621_Instantaneous stress and elongation - bar.png

= 96.24 MPa

 Now,

 δ= σL/ E = (96.24 × 106 × 2.6 )/ (200 × 109)

= 0.00125 m = 1.25 mm

Therefore, the maximums tress & elongation are 96.24 MPa & 1.25 mm, respectively.

This elongation of 1.25 mm is extremely small compared to the height of fall namely 300 mm. Let us discover the stress if this elongation were to be neglected in the calculation. While it is neglected the work strain energy equation becomes.

Wh =   (σ2/2E )× AL

or

234_Instantaneous stress and elongation - bar1.png

It shows that the error in the stress calculation is unimportant even if the elongation is neglected.

Posted Date: 1/21/2013 6:31:17 AM | Location : United States







Related Discussions:- Instantaneous stress and elongation - bar, Assignment Help, Ask Question on Instantaneous stress and elongation - bar, Get Answer, Expert's Help, Instantaneous stress and elongation - bar Discussions

Write discussion on Instantaneous stress and elongation - bar
Your posts are moderated
Related Questions
Aircraft Characteristics For planning and designing airport facilities, it is necessary to be conversant with the following important characteristics: (a) speed (b) size

Important section of fly-overs and underpasses: Culverts : A structure having a waterway upto 5 m. Minor Bridge : A structure having a waterway of 6-30 m. Medium Si

You are an engineer for WhyShopHere Toys. You have been tasked with the following: Design a child's toy to provide food for fish in an aquarium. The toy should take the fo

Compute the coefficient of friction at block: The frame shown in Figure rotates about a vertical axis. The coefficient of friction under block A is 0.4. Compute the coefficien


Evaluate the tension in the rope: Determine the tension in the rope. Solution KE of the free-body of flywheel is developed due to (i) work-done by tension T in the rop

NUCLEAR APPLICATIONS OF ELECTRON BEAM WELDING   Electron beam has been applied to the fabrication of fuel elements for pressurised water reactors and the distinct advantages


Find the maximum torque - I-section: An I-section 150 × 80 mm has flanges 6 mm thick and web 4 mm thick. Discover the maximum torque that may be safely applied if the shear st

Annotation with Leaders Ordinate dimensions are not really an dimensions at all in that they do not indicate a measurement.They annotate known as a co-ordinate points. The DIMO