Comparison of the Performance of Seamed and Unseamed Inflatable Concentrators.

摘要

Tests were run comparing seamed and unseamed inflatable concentrators. Measurements of the surface profiles showed that the effect of seams on surface accuracy was minimal. Surface errors were generally slowly varying across the membrane, exhibiting a 'W' or 'M' shape. When the membrane included seams, the result was a slight bumpiness in the error profile which retained the 'W' or 'M' shape at nearly the same level as without seams. Recent studies indicated that the major source of the surface error was more likely the variation material modulus as a function of position and stress. We used a special finite-element computer code to quantify the effect of seams; the results show again that the contribution of seams to the error in surface shape is negligible compared to the observed surface deviations in typical reflectors. The significance of these findings is that inflatable reflectors can be made inexpensively using seamed construction with no appreciable degradation of surface accuracy when compared to more expensive, continuous, formed membranes.