PSI - Issue 14

N. Venkateswaran et al. / Procedia Structural Integrity 14 (2019) 627–633 N.Venkateswaran/ Structural Integrity Procedia 00 (2018) 000–000

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4. Finite element model of Mounting Bracket Figure 2 shows the finite element model for the new assy. mounting bracket of CCS and it consists of:  Shell elements (2D elements) for all plates in the model:  Top plate = 5 mm, Stiffeners = 3 mm and Pad = 8 mm.  Coupling elements are provided from top plate to the pad to simulate the weld.  Coupling elements are provided from the center of each holes to the corresponding edge nodes of the holes.  Coupling elements are provided from the CG location of CCS to the 4 mounting holes.  Lumped mass element of 2.5 kg is provided at the CG location of the CCS.  The following Boundary Conditions (BCs) are applied in the model:  Fixed BCs are provided on all the bolt holes on the pad & the top plate.  Constraint the X-direction move (Ux = 0) on the mounting area on the top plate.

Fig. 2 FE model of Assy. mounting bracket for CCS

5. Finite Element analysis On the FE model of the mounting bracket of the CCS, the gravity load of 4 g is applied and carried out the finite element analysis. The max. von-Mises stress distribution is less than 2 MPa. After carrying out the structural analysis, it is planned to conduct the shock analysis for this bracket to estimate the strength of this bracket. 5. 1 Frequency Analysis To carry out the shock analysis, initially frequency (Eigen value) analysis is required to be done. It is understood from the vibration analysis measurement report, that the spectrum plots show the maximum resonance in the low frequency band of 0-100 Hz may be a concern for the functionality of the CCS unit, and proper care to be taken while designing the mounting structure. To cater the above requirement, the frequency analysis for the assy. mounting bracket is carried out. Various thickness of pad and different pad`s location are used to estimate the optimum Natural frequency of the mounting bracket. From different iterations of analysis, single pad with 8 mm thick, when it is placed inside of the top plate is giving first mode vibration as 130.5 Hz, is better choice for new bracket. The table 1. Shows the frequencies for the different configurations of the mounting bracket.