Introduction

Abstract

Half a century ago the first sailplanes made of glasfiber reinforced plastic (GFRP) were lifted into the air – and some of them are still in service 50 years later. Originally they incorporated the enormous potential (strength and dimensional stability) of fiber reinforced plastics (FRP). Today they prove the durability of the material. The designers and manufacturers of these very sophisticated and highly loaded structures entered unknown territory in the 1950ties. Qualification and manufacturing techniques had to be developed and the design process needed to be adapted to the new material. The fracture behavior of FRP was mainly unknown and a proper failure analysis did not exist in the middle of the last century. Today it seems almost incredible that not one of the major aeronautic companies but a group of enthusiastic engineering students designed and built the first FRP-planes. One of these pioneers was Alfred Puck who studied mechanical engineering at the Technical University of Darmstadt, Germany, at that time. He developed successfully design procedures, joined the local academic gliding group and got – for the rest of his life – fascinated by fiber reinforced plastics design. Consequently, he dedicated his professional life to the research of the material behavior and the development of FRP-structures.