GMW GMW16695 PDF

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

This procedure is used to determine the physical behavior of a sealer material under pressure conditions. The materials compressibility/rebound characteristics are determined by this procedure. This test is of particular value for materials containing fragile filler components such as glass microspheres or plastic microspheres as the results can be used to predict the crush or damage to these components under hydrostatic pressure. 

Purpose. A Johnstone Sep-Check test apparatus or equivalent (reference SAE J1864) is used to conduct this test. A sealed steel cylinder (of initial volume of 150.76 cc) is completely filled with material to be tested, loaded into the Sep-Check load frame and subjected to a progressive increase in loading upon the pressure cap. This load is applied in a manner which increases the internal hydrostatic pressure of the material by a measured increment (usually 13.8 bar/200 psi). Any displacement of the pressure cap is measured by means of a dial extensometer or Linear Voltage Displacement Transducer (LVDT). Two additional measurements are taken at each material pressure increment – the air pressure in the loading cylinder (total applied load) and the displacement of the pressure cylinder cap (total compression). By calculating and plotting the material hydrostatic pressure against the percentage compression of the material, a stress-strain plot for the material can be constructed and used to determine effective compressive modulus (resistance to compression) and filler yield point (failure limit of pressure sensitive filler components). Finally, the total material compression for a peak loading pressure can be separated into rebound (elastic) and crush (permanent) compressive elements. 

Foreword. Not applicable. 

Applicability. This test procedure is applicable to "Ultralight Sealer Materials" approved under the following specifications: GMW16070, GMW16680 and GMW3017.