nthis membrane prestressed to maintain a tensile state and to reduce deflections under applied loadings.nI found a paper (attached) that set a pre-stress (pre strain) by introducing an initial elongation(had two membrane, upper and lower membrane, defined moveable trailing edge), mentioned in part 2.1 of the papernbut in my case because of my geometry cant define this method i dont know how to apply that. by convert strain to stress found that should define 300Kpa pre stress for the purpose.n