Abschätzung des Leichtbaupotentials von Sekundärstrukturelementen

Abstract

In order to perspectively meet increasing requirements for lightweight structures in aviation, Additive Manufacturing technologies allow unlocking greater potentials in part design. With-in an aircraft, the secondary structure brackets are currently the main focus. For the evaluation of lightweight potentials of additively manufactured structural elements, a method has therefore been developed to effectively estimate the optimized part weight only based on boundary conditions, meaning without detailed geometry information. Starting point of the method is the evaluation of lightweight design separated into the dimensioning and the shape of the geometry. For that, two indicators have been defined: the Utilization factor (AF) for the dimensioning and the Minimum weight (MG) for the shape of the geometry. The Utilization factor describes the average material utilization related to the maximum permissible stress of the used material. Based on several part optimizations, the average, technically realizable Utilization factor for aircraft secondary structure was determined to be about 23% with a standard deviation of 2,5%. This value is valid for the entire part group of secondary structures. The Minimum weight however, describes the theoretical minimal amount of material needed for a part to absorb given loads within defined stress limits considering all boundary conditions. This part-individual indicator can be determined by an FE-analysis of the overall possible build room together with respective boundary conditions. Using these defined lightweight performance indicators, Utilization factor for the part group and individual Minimum weight, the future weight of an optimized part can be estimated.