OPTIMUM DESIGN OF INSULATED TENSION MEMBERS SUBJECTED TO AERODYNAMIC HEATING

摘要

A general method for determining the weight efficiency of insulated heat-sink structures is developed by which the lightest total structural weight may be found for any selected insulating and load-carrying materials. In order to simplify the analysis, a constant temperature was assumed at the outside surface of the insulation. It is shown that an optimum structural weight exists for every combination of load, insulating material, structural material, and flight time. A load parameter has been found through which it is possible to compute efficiency curves for the load-carrying materials without specifying the insulation and flight time. Charts are presented for the optimum temperatures and optimum total structural weights for beryllium, HKJIA magnesium, 2024—T4 aluminum, MST 185 titanium, 17-7PH stainless steel, and Inconel X based on an initial temperature of 75° F.nThe results show that beryllium is an excellent insulated heat-sink structural material because of its light weight and high thermal capacity. If beryllium is excepted, titanium is most efficient for short flight times and high loads;as the flight time increases and the load decreases, stainless steel and Inconel X become the most efficient materials. The results also show that, in certain ranges, the uninsulated structure is more efficient. In general, insulated heat-sink structures are most efficient where the load is high and the flight time is short.