Linear Static Behavior of Damaged Laminated Composite Plates and Shells.

Area of Science:

• Mechanical Engineering
• Materials Science
• Computational Mechanics

Background:

• Laminated and sandwich structures are susceptible to mechanical damage, affecting their performance.
• Modeling damage progression in these structures is crucial for predicting failure and ensuring safety.
• Existing models may not fully capture the complexities of damage in layered materials.

Purpose of the Study:

• To develop a mathematical scheme for modeling damaged mechanical configurations in laminated and sandwich plates and shells.
• To investigate the effects of progressive damage on structural behavior using parametric studies.
• To compare the efficacy of different Higher-order Shear Deformation Theories (HSDTs) in modeling damaged structures.

Main Methods:

• Introduction of two-dimensional Gaussian and ellipse-shaped functions to represent material property degradation.
• Parametric studies varying geometric parameters of damage functions to analyze various damaged configurations.
• Application of an a posteriori recovery procedure based on 3D equilibrium equations for shell structures.
• Utilizing a unified formulation for Higher-order Shear Deformation Theories (HSDTs), including Murakami's zig-zag function.
• Solving the static problem using the Generalized Differential Quadrature (GDQ) method.

Main Results:

• Demonstrated ability to model various damaged configurations by adjusting parameters of Gaussian and elliptical functions.
• Analysis of progressive damage effects on displacement profiles and through-thickness variations of stress, strain, and displacement.
• Comparison of different HSDTs and kinematic expansion orders for their effectiveness in handling damaged structures.
• Validation of the GDQ method's accuracy and stability through convergence analyses and comparison with finite element software.

Conclusions:

• The proposed mathematical scheme effectively models damage in laminated and sandwich structures.
• The study highlights the influence of damage distribution and severity on structural response.
• The comparison of HSDTs provides insights into selecting appropriate models for analyzing damaged layered composites.
• The GDQ method proves to be a reliable and accurate numerical tool for this class of problems.