APPLICABILITY OF THE ST. VENANT PRINCIPLE IN THE THEORY OF THIN ELASTIC ENVELOPES UNDER THE EFFECT OF FORCE AND TEMPERATURE B. V. Nerubailo and T. B. Nerubailo UDC 539.3 The stressed-and-strained state of the most unfavorable representatives of envelopes of zero Gaussian curvature from the point of view of applicability of the St. Venant principle - the cylindrical ones - under forces and temperature fields with piecewise-smooth variation along the genetratrix and cosinusoidal variation along the contour is investigated. Results of an experimental investigation of the envelopes are presented. JEPTER74920199920 JEPTER7492020