Weight reduction of radar platform : Concept development, analysis and evaluation

Sammanfattning: The aim of this master thesis has been to produce and evaluate a set of lightweight concepts for a radar system mounting platform. The evaluation aims to cover relevant aspects specifically regarding the Saab Arthur weapon locating system, as well as the Saab Giraffe 4A multifunctional radar system. By request of Saab, weight reduction is the main performance gain of interest and this is therefore given high emphasis in the concept evaluation performed. Four concepts are developed through brainstorming and current market studies. These four concepts are briefly evaluated and two carbon fibre reinforced plastic (CFRP) based concepts are deemed the most promising. The remaining concepts are therefore disregarded in order to allow for more in-depth evaluation of the more promising CFRP concepts. The main structural evaluation is performed with the help of finite element analysis (FEA) that is preprocessed, solved and post processed in PTC Creo Simulate 3.0. The computer assisted design model (CAD-model) that is used as a basis for the FEA-model is created in PTC Creo 3.0. Due to the structural complexity of the current radar platforms, considerable simplifications of the structural geometry in the CAD-model and subsequently the FEA-model is necessary. In order to ensure proper benchmarking in a comparative study against current design of the radar platform, all cad- and FEA-models are modelled with the same simplifications. This ensures comparable results between the concepts being evaluated and the current design. The composite based concepts give rise to certain issues that require new solutions such as electromagnetic interference (EMI) shielding, joining of CFRP laminates and mounting equipment on CFRP laminates. In order to gain a sense of how problematic these issues are, solutions are identified through a study of currently used methods in other areas within Saab such as the Visby corvette [1] as well as external literature. In depth investigation such as FEA analysis and testing of such solutions is however outside the scope of this thesis and needs to be performed at a later stage if further resources towards realization are committed by Saab. The final conclusion of this work marks a balance between cost and performance gains. Carbon fibre reinforced plastic is expensive and manufacturing requires new methods, but the gains can be very significant in form of considerable weight savings of up to 35%. The identified issues with a composite radar platform such as EMI shielding do have realistic solutions but require significant further work.