An extensive and varied test program was carried out on four GRP rod and rope materials to evaluate tensile strengths, moduli of elasticity, flexibility at low temperatures, effects of simulated Aeolian vibration, and stress-rupture properties at moderate elevated temperatures both with and without high humidity. The effects of elevated temperature on long-term storage capabilities were investigated, and diametertemperature relationships were established for avoiding buckling due to storage in a coiled condition.The performances of five commercially available end fittings on these materials were examined in terms of the breaking loads attained in tensile tests. Using finite-element analyses, an improved end fitting was developed. With this end fitting the strength of the fitting-specimen system approaches the true tensile strength of the specimen for two of the GRP materials. An experimental stress analysis of the improved fitting was performed.

The Consumer Product Safety Conmission has promulgated a safety standard for bicycle braking systems based on the stopping distances achieved in road tests under specified conditions. This report presents an error analysis of the test method, for the Commission's use in justifying or modifying the test criteria. The error analysis is based on experimental data, for the most part, and on theoretical principles where sufficient data are lacking. The theory, a kinetic analysis of the bicycle braking process, is included in the report together with proposed definitions of terms intended to quantify important aspects of bicycle braking performance.The error analysis produced estimates of rather large lab-to-lab and test-to-test variabilities to be expected from the test method. These, in turn, were found to be principally dominated by errors resulting from an incorrect overweight-rider allowance specified by the Commission, and by variations in rider reaction times, respectively. Suggestions are made for more accurate methods of accommodating variations in rider mass, for reducing the effects of the test-to-test variability, and for reducing the danger of pitchover in the performance of the road test.

A bank of six JUUUU-ibf-capacity creep testing machines was designed and is being assembled. These machines, which will accommodate 9-ft specimens, are equipped with environmental chambers for stress-rupture tests up to 200°F under saturated humidity conditions.

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The profuse variety of aircraft bolts which is available has made the evaluation and specification of bolts for engine and structural use extremely complex, particularly insofar as fatigue and hot fatigue environments are concerned. The state of knowledge of fatigue of bolts and bolted joints is surveyed and critically appraised in terms of aeronautical practices. Using this material as a basis , recommendations are made regarding the evaluation and specification of aircraft bolts for fatigue situations and regarding the growing problem of errors in fastener replacement.