Antisymmetric grain support test device and methods

A testing apparatus for use in a tensile testing machine for simulating thermal, acceleration, and ignition pressurization loads upon a grain support system of a solid rocket motor during ignition, comprising:

• an antisymmetric test specimen having first and second opposing sides and first and second opposing ends and including flap hinges antisymmetrically disposed on the first and second sides of the specimen;
• a first L-shaped test fixture including an end segment and a side segment, the side segment bonded to the first side of the test specimen and to the flap hinge disposed on the first side of the test specimen, said attachment of the first test fixture to the test specimen being the sole means of transferring a load from the first test fixture to the test specimen, the end segment of the first test fixture further including a first rotatable mounting mechanism for mounting the first test fixture in a tensile testing machine, the rotatable mounting mechanism configured to permit rotation of the first test fixture as a load is applied to the test specimen;
• and
• a second L-shaped test fixture including an end segment and a side segment, the side segment bonded to the second side of the test specimen and to the flap hinge disposed on the second side of the test specimen, said attachment of the second test fixture to the test specimen being the sole means of transferring a load from the second test fixture to the test specimen, the end segment of the second test fixture further including a rotatable mounting mechanism for mounting the second test fixture in a tensile testing machine, the rotatable mounting mechanism configured to permit rotation of the second test fixture as a load is applied to the test specimen, thereby permitting the application of uniaxial tension to the midline of the test specimen.

A process for simulating thermal, acceleration, and ignition pressurization loads upon the grain support system of a solid rocket motor during ignition, comprising the steps of:

• preparing an antisymmetric test specimen in which the grain support system of the solid rocket motor is reproduced along each side of the specimen such that the reproduced grain support systems are antisymmetrically disposed with respect to each other;
• attaching a side segment of an L-shaped test fixture to each side of the test specimen, each L-shaped test fixture including an end segment configured with a rotatable mounting mechanism for mounting the test fixture in a tensile testing machine, each rotatable mounting mechanism configured to permit rotation of the test fixture to which it is mounted as a load is applied to the test specimen, said attachment of the test fixtures to the test specimen being the sole means of transferring a load from the test fixtures to the test specimen;
• connecting the L-shaped test fixtures to a tensile testing machine at the rotatable mounting mechanisms;
• and
• applying tension to the test specimen.

An apparatus for evaluating the effects of uniaxial tension to the midline of a test specimen, comprising:

• an antisymmetric test specimen having first and second opposing sides and first and second opposing ends;
• a first L-shaped test fixture including an end segment and a side segment, the side segment capable of attachment to the first side of the test specimen such that the end segment is disposed adjacent the first end of the test specimen;
• and
• a second L-shaped test fixture including an end segment and a side segment, the side segment capable of attachment to the second side of the test specimen such that the end segment is disposed adjacent the second end of the test specimen;
• wherein the side segments of the first and second L-shaped test fixtures are bonded to the sides of the test specimen and at least a portion of sides of the test specimen which are mounted to the test fixtures are made of insulation which is bonded to the side segments of the first and second L-shaped test fixtures through vulcanization.