A1/SSCO/June/2020/M50/LD-June 29
SCHOOL OF MECHANICAL ENGINEERING
Class Assignment – I
Special Summer Course Online @ MT
Last Date: 29th June, 2020 @ 12:59 PM (IST)
Programme Name & Branch: B Tech (Summer Special Term)
Course Name Code: MEE2015
Course Name: Non-destructive Testing
Faculty Name(s): Dr. Saurabh Gupta
Class Mode(s): Online / Microsoft Team
Total Pages: 2 (Problems are six) Maximum Marks: 50 General instruction(s):
All Questions are compulsory
Assume suitable data if required
All Questions are compulsory (each question carries 10 marks)
1- (a) Describe how the pre-cleaning and cleaning steps in the penetrant process affect the effectiveness of liquid penetrant inspection test in NDT. [5 M]
(b) How does improper dwell time affect the effectiveness of a penetrant
inspection? [5 M]
2- An experiment was conducted in the -Hylem- sample (see attached figure) using the Pulse-Echo technique (2.75 MHZ-operating frequency), where a time trace signal was recorded as shown in the figure below. Calculate the longitudinal wave velocity (m/sec), and depth of the crack in the sample (in terms of operating wavelength).
[5 M] [10 M]
By DR. SAURABH GUPTA SR.AP@VIT Vellore saurabh.gupta@vit.ac.in A1/SSCO/June/2020/M50/LD-June 29
3- Show that is a solution of the plane wave equation
where: – wave propagation velocity, – represents in spatial and time
domain. Assume is the time-varying axial displacement . [5 M]
4- Compare the wavelength for the 1.0 and 5.0 MHz longitudinal waves in aluminum and steel and provide the significant comments based on the wavelength to detect cracks of the 0.5 mm (average) size. The mechanical properties for aluminum and
steel are as follows: [10 M]
S. No. (Poisson ratio) ? (Kg/ ) ×
Steel 200 0.31 7.7
5- Consider the one-dimensional wave equation , sketch the behaviour of for various times and explain which the
forward wave is and which the backward wave is. [10 M]
6- How the fallowing parameters influence successful non-destructive inspection of materials: [10 M]
(a) Human factors
(b) Material
(c) Flaw location
(d) Flaw size and its orientation (e) Frequency of inspection
By DR. SAURABH GUPTA SR.AP@VIT Vellore saurabh.gupta@vit.ac.in