Comparison of Experimental Modal Analysis Results with Standard Finite Element Software ABAQUS for Healthy Laminates
Finite element modeling of healthy composite plates is carried out using a standard finite element software package ABAQUS. Conventional solid element is extruded with composite layup to model the composite plate. A fine mesh size of 0.004 mm is used for accurate prediction of modal frequencies. First four modal frequencies are obtained through experimental modal analysis carried out on healthy laminates of different orientations. The comparisons between the experimental and numerical analyses results for the representative modes are presented in Table 37.4.
Table 37.4: Comparison of EMA and ABAQUS results
Laminate
|
Mode type |
B1(Hz) |
Tl(Hz) |
B2(Hz) |
B22(Hz) |
B32(Hz) |
B02(Hz) |
Healthy 0o plies |
Experiment
ABAQUS |
32.5
28.03
|
56.3
46.18 |
146.3
129.24 |
285.2
272.14 |
-
- |
-
- |
Healthy 90o plies |
Experiment
ABAQUS |
25.0
23.88 |
45.1
41.68 |
81.3
98.84 |
-
- |
238.3
221.38 |
-
- |
Healthy 0o /90o plies |
Experiment
ABAQUS |
27.5
25.05 |
63.8
46.18 |
143.8
129.24 |
-
- |
-
- |
278.8
258.92 |
A standard FEM Package ‘ABAQUS' is used for modal analysis of healthy composite plates to verify and validate the results of experimental modal analysis. A fairly good agreement in natural frequencies for different modes is seen for various ply orientations. The modal frequencies predicted by ABAQUS for different orientations of composite laminates are on the lower side in comparison to the experimental results for all the modes. The agreement in results is very good in general for higher frequency modes. Prediction of first modal frequency is in close conformity with the experimental results for all 900 plies and cross ply laminates while for all 00 plies, the results are somewhat conservative in comparison to the experimental results.
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