This document discusses two methods for testing the breaking strength of textile specimens: constant rate of loading (CRL) and constant rate of elongation (CRE). Under CRL, a specimen is gripped while a constant force is applied, extending the specimen until it breaks. Under CRE, a specimen is gripped while the bottom jaw moves at a constant velocity, elongating the specimen and developing tension until it breaks. Both methods measure the load and extension at break to determine breaking strength.

2. Subrata Kumar Sarker
ID: 151014002
Department of Textile Engineering

3. Name of My Presentation
CRL & CRE METHOD

4. LOAD: The application of a load to a specimen in its axil
direction causes a tension to be developed in the specimen.
The load is usually expressed in gm wt or pounds wt.

5. Breaking load: The load at which material breaks is
called breaking load. It is usually expressed in gm-wt.

6. Breaking length: the breaking length is length of the
specimen which will just break under weight when hang
vertically. Units of braking length is kilogram.

7. Constant Rate of loading:
 A specimen ‘A’ is gripped
in a fixed top jaw j1 and
in a bottom jaw j2 which
is moveable.
 A force F is initially zero
but increasing at
constant from zero, is
applied to the specimen
along the directions
shown in figure.
 Due to applied force, the
specimen will be
extended until it
eventually breaks.
 The loading has thus
caused the elongation.

8. Constant rate of Elongation
• A specimen ‘B’ is gripped in
the fixed top jaw ‘j1 a and in
the bottom jaw j2 which is
moveable downwards.
• The bottom jaw j2 can move
downwards at a constant
velocity by means of a screw
mechanism.
• Initially the tension in ‘B’ is
zero but when the bottom
jaw j2 moves downwards the
specimen is extended and an
increasing tension is
developed until the
specimen finally breaks.
• In this case the extension
causes loading.