FED-STD-228A
Method 3041.1
18 APRIL 2014
TENSILE STRESS, INSULATION AND SHEATH
1. SCOPE
1.1 This method is intended for use in determining the tensile stress of insulation and sheath
compounds. It is applicable to the usual grades of rubber and thermoplastic compounds used for
insulation and sheaths.
2. SPECIMEN
2.1 The specimen should be as described in method 3021.
3. APPARATUS
3.1 The apparatus shall be as described in methods 3021 and 3031.
4. PROCEDURE
4.1 Unless otherwise specified in the detail specification, the tensile stress shall be determined on the
same specimen and at the same time as the tensile strength and elongation.
4.2 The elongation in percent at which the tensile stress is to be determined shall be as specified in the
detail specification.
4.3 Preparation of specimen. The specimen shall be prepared as described in methods 3021 and 3031.
4.4 Cross-sectional area. The cross-sectional area of the specimen shall be determined as described in
method 3021.
4.5 Determination of tensile stress. The procedure for tensile stress shall be the same as for tensile
strength and elongation, methods 3021 and 3031, except that the force in pounds necessary to stretch
the specimen to the required elongation shall be recorded.
5. RESULTS
5.1 Calculation. The tensile stress of the specimen shall be calculated as follows:
Tensile stresses, p. s. i., = _F__
C
where:
F=force in pounds required to stretch the specimen to the required elongation
C=cross-sectional area of the unstretched specimen in square inches (4.4)
5.2 Unless otherwise specified in the detail specification, three specimens from each inspection unit shall
be tested except that under the following conditions five specimens shall be tested:
5.2.1 If the tensile stress of one or more specimens does not meet the specified requirement for tensile
stress in the detail specification.
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