NG stand mechanical interface analysis for vehicle integrated RBS 70 NG

Sammanfattning: RBS 70 was introduced 1978 in Sweden and developed to be counter threats on the battlefield. This weapon is efficient against both conventional and small targets. Main components of the system are stand, sight and missile in container. RBS 70 NG with three legs is named as MANPADS configuration and has requirements for the natural frequency in launching direction to 4-6 Hz when placing it to a concrete ground.This Master Thesis has focus on vehicle integrate system, which requires legs to be removed from the MANPADS configuration and put it on a platform placed on a vehicle. For the vehicle integrated system 3.5 Hz will be acceptable as the lowest natural frequency. Four different concepts were purposed and evaluated for the mechanical interface between RBS 70 NG system and weapon platform: Existing platform with fix interface between RBS 70 NG system and platform where the thickness of the roof plate is 5 mm (named as reference model). Modified platform with thick plate (thickness of 30 mm) and fix interface between RBS 70 NG system and platform. Existing platform with damped interface between RBS 70 NG system and platform where the thickness of the roof plate is 5 mm. Modified platform with thick plate (thickness of 30 mm) and damped interface between RBS 70 NG system and platform.The final concept should meet the main requirements of SMU (Stabilized Mirror Unit) and simultaneously keep natural frequency for RBS 70 NG system within requirements.A theoretical evaluation of the longitudinal stiffness for the dampers has been calculated in the report and inputted as the value of the dampers in ANSYS R18.1. Modal analysis and harmonic response analysis was performed for all proposed concepts.Magnification ratio calculation for a system without dampers will illustrate that the upcoming amplitude for the 5 mm plate will amplified more than 30 mm plate at coherent frequencies.By studying the results it illustrates that a plate with thickness of 30 mm helps to minimize the disturbance in elevation direction but not in azimuth direction. To minimize the disturbance in all directions concepts with dampers will be a satisfied solution.