Design Analysis ‘n Manufacturing By - Yogesh Arora and Sangam Sinha

CZT – Imager Payload Structural Configuration Initial structural configuration of the payload was set keeping following fundamentals 1. Past experience 2. Weight constraint 3. Science requirements

Analysis Objectives Based on Static and Dynamic load conditions provided by ISRO following objectives were drawn 1. Natural frequency of CZT Imager assembly 2. To check stresses and deformations on all parts of the assembly, particularly fasteners surroundings under static and dynamic load conditions 3. To optimize Fixed and Structural mass

Assumptions and Boundary Conditions All Fixed masses are rigid bodies Collimator plates are rigidly integrated The payload is considered fixed in translation and rotation at the bolted locations on the deck The assembly has been considered as integration of finite discrete masses, hence posing a case of Multi-Degree-Freedom- System in fundamental co-ordinate system

Analysis technology and meshing details Finite Element method is applied for Eigen Analysis using IDEAS, FEMAP and NASTRAN software Total number of elements – Total number of beam elements – 1209 Total number of shell elements – Total number of lumped mass elements – 64 Total number of nodes Total degree of freedom -

Weight breakup of CZT Imager ComponentWeight (Kg) Cross0.238 Collimator23.86 Calibration housing2.181 PCB with CZT modules10 CSI box16.2 CSI housing2.051 Electrical housing2.745 HV box1.877 ALPHA box1.117 Fasteners0.171 Total weight60.44

load cases Load Case Description 1Self Weight 220 G out-of-plane (+ve Z direction) 315 G in-plane (+ve Y direction) 420 G out-of-plane (+ve Z direction) + 15 G in- plane (+ve Y direction)

Results Iteration 01 Eigen Analysis Iteration No.DescriptionFundamental Natural Frequency 10.7mm structural wall thickness and 1mm for flanges and minimum bolting locations 26 Hz 2 0.7mm structural wall thickness and 1mm for flanges and increased bolting locations (24 places) 38.5 Hz 3Increased structural thickness (1mm on walls and 2mm for flanges) and minimum bolting locations 53.5 Hz 4Increased structural thickness (1mm on walls and 2mm for flanges) and increased bolting locations (24 places). 75 Hz

Mass participation details of iteration 04, up to mode 3 X direction (mode 1) Y direction (mode 2) Z direction (mode 3) Total Mass Mass participate d Percentage

Iteration 04 – Principle Mode Shape

Static analysis results Load case Maximum displacement (mm) Von – mises stress (N/mm ²)Remarks 11.85E-02Plate elements near bolts – 4 Stiffeners/flanges – 2.22 Bolts – Plate elements near bolts – 89 Stiffeners/flanges – 35.5 Bolts – 68.5 Corner bolts in CSI, Dummy hsg and adjoining plate elements experiences max stress and deflection 31.03Plate elements near bolts – 75.5 Stiffeners/flanges – 20 Bolts – 115 Bolts on the cross, Corner bolts in CSI, Dummy hsg and adjoining plate elements experiences max stress and deflection 41.03Plate elements near bolts – 117 Stiffeners/flanges – 45 Bolts – 178 Bolts on the cross, Corner bolts in CSI, Dummy hsg and adjoining plate elements experiences max stress and deflection

The Next Step On the current baseline new team with members from ISAC and TIFR has been formed to reconfigure the whole system New team has tasks e.g. to minimize weight, analyze every part in detail, rearrange mounting arrangement etc.

Manufacturing Besides several highly accurate conventional machines our workshop houses 3 CNC Milling machines, 1 CNC lathe, 1 NC EDM and 2 high precision DECKEL universal milling machines The workshop also possesses advanced pulse controlled TIG, Plasma welding and cutting machines Thus our workshop enjoys the status of both, a well-equipped precision Tool Room and a reliable fabrication shop.