Designing Universal Yoke Structure of Suspension and Release System with Topology Optimization for Fighter Aircrafts

Abstract

In the aviation industry, a design with a sensitive and low margin is more important than any vehicle production. Within the scope of this study, the design road map of a product intended to be used in fighter aircraft is explained and it is aimed to bring an example study to the literature of our country. Due to the maneuvers of the fighter aircraft and the environmental conditions, it was desired to find out which loads were affected on this structure. Weapon systems were selected as sample application, duties and working principles of the suspension and release systems were explained in detail. General literature and studies about ejector release units and weapons were examined, information was given about structural design and lightening studies. Then, loads on the ejector release unit and weapon due to the movements and environment of the fighter aircraft were calculated. In addition, the forces required to safely separate these weapons from the aircraft were explained and included in the process. A multi-purpose and compatible yoke structure has been considered for the purpose of carrying air-air and air-surface weapon with the same release system, which has not been applied before. The yoke structure is modeled in the SolidWorks program according to the requirements. The material selection from alternatives is aimed to be realistic in terms of our country's literature and opportunities. In the ABAQUS program, design spaces and constraints were selected and analyzed using the finite element method under different multi load cases of beyond vision missile and 1000lb bombs. Necessary weight reduction and topology optimization studies were carried out with the TOSCA module in the analysis program. The surface smoothing process was applied to this yoke structure which was optimized and lightened after the design. Different yoke design alternatives that can be considered separately for bombs and missiles were also subjected to relevant loads and the resulting stress values were examined, compared with the current results of the optimization geometry, and the multi-purpose designed structure was evaluated to be efficient. This structure, which was calculated as 705 grams after optimization, decreased to the desired weight level. In the case of maximum loading, 2 as a safety factor has been chosen for the material yield value. Since the yield strength of the material 17-4PH H1025 is 1170 Mpa, the analysis results should be less than 585 Mpa. As a result, the maximum stress in the yoke calculated as 521 MPa and this strength remained below the limit. It was concluded that this geometry would not create a risky situation for safe flight and seperation after designing with topology optimization.