A Study on the Failure Behavior and Force Transmission of Composite Skin-Stringer Structures Under a Compressive Load

Area of Science:

• Materials Science
• Mechanical Engineering
• Aerospace Engineering

Background:

• Carbon fiber-reinforced composites are crucial for aircraft structures, enhancing performance and safety.
• Understanding the load-bearing capacity and failure mechanisms of composite skin-stringer structures is vital for structural integrity.

Purpose of the Study:

• To develop and validate a novel computational model for analyzing the complex failure and load transmission behavior of T800/3900S-2B fiber-reinforced composite skin-stringer structures under compressive loading.

Main Methods:

• Experimental compression strength tests were performed on a composite stringer/skin structure.
• A three-dimensional Finite Element Method (FEM) model was developed using Abaqus/Standard 2022.
• The FEM incorporated modified 3D Hashin initiation criteria and the Tserpes degradation law via a UMAT subroutine to simulate in-plane ply and interlaminar damage.

Main Results:

• The developed FEM model showed high similarity with experimental data for load-displacement curves.
• Simulated failure modes, including matrix compressive cracking, fiber compressive failure, and fiber-matrix shear-out failure, closely matched experimental observations.
• The model effectively captured complex failure and load transfer phenomena in the composite skin-stringer structures.

Conclusions:

• The study presents an efficient and accurate FEM model for simulating composite skin-stringer structures.
• This model significantly advances the understanding and prediction of failure and load transfer in these critical aircraft components.
• The validated model can aid in the design and safety assessment of composite aerospace structures.