1 / 18

Analysis of Simply Supported Composite Plates with Uniform Pressure using ANSYS and Maple

Analysis of Simply Supported Composite Plates with Uniform Pressure using ANSYS and Maple. Second Progress Report 11/28/2013. Thin Plate Theory. Three Assumptions for Thin Plate Theory There is no deformation in the middle plane of the plate. This plane remains neutral during bending.

allan
Download Presentation

Analysis of Simply Supported Composite Plates with Uniform Pressure using ANSYS and Maple

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Analysis of Simply Supported Composite Plates with Uniform Pressure using ANSYS and Maple Second Progress Report 11/28/2013

  2. Thin Plate Theory Three Assumptions for Thin Plate Theory • There is no deformation in the middle plane of the plate. This plane remains neutral during bending. • Points of the plate lying initially on a normal-to-the-middle plane of the plate remain on the normal-to-the-middle surface of the plate after bending • The normal stress in the direction transverse to the plate can be disregarded

  3. Material Properties and Governing Equations • wmax = α*q*a4/D • D = E*h3/12*(1-ν2)

  4. ANSYS Model with Mesh • Due to Symmetry only a quarter of the plate needs to be modeled • The mesh size has an edge length of 0.75” • Side 1 and Side 2 are constrained against translation in the z-direction. • Side 2 and Side 3 is constrained against rotating in the x-direction • Side 1 and Side 4 is constrained against rotation in the y-direction • The origin is constrained against motion in the x- and y-directions • A pressure of 10 psi is applied to the area Side 1 Side 1 Side 4 Side 4 Side 2 Side 2 Origin Origin Side 3 Side 3

  5. Results of Aluminum Plate • From governing equations:wmax = 0.941399” • From ANSYSwmax = 0.941085” • % Error = 0.033%

  6. Material Properties of Composite Laminate

  7. Governing Equations ABD Matrix: Analysis and Performance of Fiber Composites: Agarwal & Nroutman

  8. Governing Equations (cont.) For Cross-ply Laminates the [D] matrix simplifies and the governing equation reduces to: Mechanics of Composite: Jones

  9. Governing Equations (cont.) • For symmetric angle laminates, the ABD matrix is fully defined. • The boundary conditions for a symmetric angle laminate are:

  10. Governing Equations (cont.) • Using the Rayleigh-Ritz Method based on the total minimum potential energy will provide an approximation of the deflection of the plate

  11. ANSYS Model with Mesh • Due to Symmetry only a quarter of the plate needs to be modeled • The mesh size has an edge length of 0.75” • Side 1 and Side 2 are constrained against translation in the z-direction. • Side 2 and Side 3 is constrained against rotating in the x-direction • Side 1 and Side 4 is constrained against rotation in the y-direction • The origin is constrained against motion in the x- and y-directions • A pressure of 10 psi is applied to the area Side 1 Side 1 Side 4 Side 4 Side 2 Side 2 Origin Origin Side 3 Side 3

  12. Results of Composite Plate • Composite Plate Results • [0 90 0 90]s Laminate • From governing equations:wmax = 0.7146” • From ANSYSwmax = 0.7182” • % Error = -0.5%

  13. Results of Composite Plate (ANSYS)

  14. Failure Criterion

  15. Failure Criterion (cont.) • The Tsai-Wu Failure Criterion is based on the following equations:

  16. Failure Criterion (cont.) Maximum Stress Criterion for bi-axial loading of composite plate:

  17. Failure Criterion (cont.) Tsai-Wu Criterion for bi-axial loading of composite plate:

  18. Conclusions • The composite plate that had the smallest deflection was the 12 ply [+/-45 +/-45 +/-45]s laminate. • The thinnest plate that had the smallest deflection was the 8 ply [+/-30 +/-30]s and [+/-60 +/-60]s laminates • The larger percent error for the results occurred for the symmetric angle ply trials. This is because of the nature of the Rayleigh-Ritz Method. When the composite has symmetric angle plies there is a full [D] matrix. The full [D] matrix does not allow for a separation of variables method to be used to calculate the deflection because not all of the boundary conditions can be satisfied. The Rayleigh-Ritz Method approximates the deflection by using a Fourier expansion for the total potential energy. • The calculated percent error seems to be within reason for the analysis that was done for this project. The Rayleigh-Ritz Method does not provide an exact solution when compared to the method for a specially orthotropic plate. • The most reasonable plate arrangement that would be suitable for replacing the aluminum plate is the 8 ply orientations of [+/-30 +/-30]s, [+/-45 +/-45]s, [+/-60 +/-60]s. These three ply combinations can withstand a significant stress in the 1-direction, 2-direction, and 12-direction (shear) in comparison to other composite plates. These 8 ply plates will also be marginally thicker than the 0.25" aluminum plate, but provide a significant decrease in overall weight.

More Related