STATIC AND DYNAMIC CREEP PROPERTIES OF LAMINATED PLASTICS FOR VARIOUS TYPES OF STRESS

摘要

Creep tests of fire laminated plastics were made in this investiga¬tion to determine the relative creep properties of these materials when subjected to various types of static and dynamic stresses. Creep defor¬mations were measured to determine the variation of these deformations with stress. For each type of test, the stress values investigated covered the stress range from zero stress to the ultimate strength-of the material. Static creep tests were made for tension, bending and torsion, and the creep behavior, was studied for fluctuating axial loads superimposed on static tensile loads. In general, the various kinds of creep tests show that the creep deformation resistance varies' with the ultimate tensile strengths of the laminates except for the torsion creep tests of square cross sections. Attempts were made to interpret the creep test results for the purpose of obtaining a stress-creep rate re¬lation. The leg-log, log and hyperbolic sine methods of interpretation were used. The agreement between these metnods of interpretation and the test results was not satisfactory so that the results of these in¬terpretations are not included in this report.