The document discusses the development of an experimental setup for dynamic strain measurement. It describes different types of strain and methods for strain measurement, both static and dynamic. The aim is to study various static strain instruments, compare them to dynamic instruments, and develop structural models to measure strain under static and dynamic loads. Literature is reviewed on previous uses of strain gauges, accelerometers, and fiber optic sensors to monitor bridge responses and calculate modal parameters under traffic loading.

1. First seminar on
Department of Applied Mechanics
VISVESVARAYA NATIONAL INSTITUTE OF
TECHNOLOGY
Submitted by
SWAPNIL .K. DANI
Guide
Dr. G. N. RONGHE
 DEVELOPENT OF EXPERIMENTAL SETUP
FOR DYNAMIC STRAIN MEASUREMENT

2.  Introduction
 Literature review
 Aim of present study
 References
Contents

3. TYPES OF STRAIN
 LINEAR STRAIN
Ratio of change in length due to deformation to original length.
 LATERAL STRAIN
Ratio of change in length of the body due to deformation to its original length in
directional perpendicular to force.
 VOLUMETRIC STRAIN
Ratio of the change in the volume of the body to the deformation to its original
volume.
 SHEAR STRAIN
It is the strain accompanying a shearing action

4. METHODS FOR STRAIN MEASUREMENT
Static strain measurement Dynamic strain measurement
Figure 1
Source: http://www.kyowa-ei.co.jp
Figure 2
Source: http://www.kyowa-ei.co.jp

5. DIFFERENT METHODS FOR STRAIN MEASUREMENTS
1) Grid method, brittle coating.
2) Electrical-resistance strain gauges.
3) Calibration of strain gauges.
4) Bridge circuit for strain gauges.

6. INSTRUMENTS
USED
Strain gauge
Vibrating wire strain
gauge(VWSG)
Electrical strain
gauge(ESG)
Optical fiber Bragg
grating(FBG)
Extensometer
Tape
extensometer
Borehole
extensometer
Accelerometer Pressure
Transducers
Temperature
sensors

7. 1. Small & lightweight
2. Digital value , bar graph , storage
data etc.are displayed
3. Sampling wave recording
4. Built in bridge box
LAB INSTRUMENT FOR DYNAMIC
STRAIN MEASUREMENT
Figure 3
Source: http://www.tml.jp
DYNAMIC STRAIN METER

8. 1. Compact & lightweight
2. Large capacity data memory
3. Data visualization and data transfer
4. Easy to grip and portable
Figure 4
Source: http://www.tml.jp
DIGITAL STRAIN METER

9. LITERATURE REVIEW
Cook and Ventura (1999) described the dynamic strain testing of the Lindquist
bridge. The dynamic characteristics of the bridge were investigated by using six
strain gauges , one displacement sensor , and one temperature gauge.
Hou and Lynch (2006) here the use of low-cost and easy-to-install wireless
sensors to record bridge responses during short-term load testing is studied.
A combination of strain gages , accelerometers and transducers are used . First the
acceleration response of the bridge is monitored by the wireless system during
routine traffic loading , also modal parameters are calculated by the wireless
sensors .

10. Casadei et al.(2008) paper highlights the emerging alternatives for health
monitoring by using fiber optic sensing technology . Strain profiles along the
steel girders of a continuous slab-on-girder bridge are obtained by using
optical fiber sensors.
Rutz et al.(2008) in this paper took into account the effect of wind pressure
to determine the structural adequacy of the structures . Strain transducers have
been used extensively tested in laboratory to verify reliability .
Stepanova et al.(2013) considered design principles for three high-
performance microprocessor multi-channel strain-gauge system used in
dynamic test of different structures. Strain gauges power supply is activated
for short periods to measure the deformations of a structure.
LITERATURE REVIEW

11. AIM OF PRESENT STUDY
 Study of various static strain measuring instruments used on
Structures
 To find out limitation of static strain instruments over dynamic strain
measuring instruments.
 To study the behaviour of the strain gauges attached to the surface of
Structure.
 Development of structural models in laboratory for static and dynamic
strain measurement.
 Determining bending moments, deflection profiles using relevant
software's.
 Comparing experimental and analytical results.

12. REFERENCES
1) Cook, S.E., and Ventura, C.E. (1999). “Dynamic strain measurements of the Lindquist
bridge.” 17th International Modal Analysis Conference , Vancouver, B.C., Canada
SPIE proceedings series A. 1999, vol. 3727, 2, pp. 903-907.
2) Dalley, J.W., and Rilley, W. F. (1991). Experimental Stress Analysis, McGraw Hill
International editions, USA .
3) Herrero, T. V., Rutz, F. R., Rens, K.L. (2008). “ Wind Pressure and Strain
Measurements on Bridges. II: Strain Transducer Development ”, Journal of
performance of constructed facilities A. 2008, vol. 22, No.1, pp. 12-23.
4) Hou, T.C., and Lynch, J.P. (2006). “Rapid-to-deploy wireless monitoring systems for
static and dynamic load testing of bridges :Validation on the grove street bridge.”
Proc.,13th Annual International Symposium on Smart Structures and Materials.
San Diego, pp. 61780D.1-61780D.12.

13. 5) Kamrujjaman Serker, N.H.M., and Wu, Z.S. (2010). “ Structural health monitoring
using static and dynamic strain data from long-gage distributed FBG sensor.”
IABSE-JSCE Joint conference on Advances in Bridge Engineering-II.
(August 8-10), Dhaka, Bangladesh.
6) Matta,F.,Bastianini, F., Galati,N., Casadei,P., and Nanni,A.(2008). “Distributed
Strain Measurement in Steel Bridge with Fiber Optic Sensors: Validation
through Diagnostic Load Test.” Journal of performance of constructed facilities,
ASCE ,Vol. 22, No. 4, pp.264-273.
7) Singh, S. (2012). Experimental Stress Analysis, Khanna publishers, New Delhi,
India.
8) Stepanova, L.N., Kabanov, S.I., Bekher, S.A., and Nikitenko, M.S. (2013).
“Microprocessor Multi-channel Strain-gauge Systems for Dynamic Tests of
Structures”, Journal of Automation and Remote control ,Vol 74,No.5, pp. 891-897.