Linear-Nonlinear Stiffness Responses of Carbon Fiber-Reinforced Polymer Composite Materials and Structures: A Numerical Study

Abstract

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures.

Linearization of Composite Material Damage Model Results and Its Impact on the Subsequent Stress–Strain Analysis

“…The nonlinear formulation of the problem shown by the relationship between material damage and effective stress [ 1 ] can be calculated using Equations (4) and (5), which shows the damage operator [ 1 , 6 , 7 , 10 , 11 , 12 ]. …”

“…If this condition is violated, the task becomes poorly conditioned and the calculation cannot be successfully performed [ 3 ]. However, the phenomenon of force drop in the model occurs in all tasks that are focused on the study of the state of structures in a broken state [ 4 , 5 , 6 , 7 ] beyond the strength reached before total structural collapse [ 8 , 9 , 10 , 11 , 12 ]. This can occur, for example, due to a collision between fast-moving objects [ 13 ].…”

Lightweight Glass Fiber-Reinforced Polymer Composite for Automotive Bumper Applications: A Review

“…In automobile applications, the material should withstand extreme environments such as sudden impact and variable loads. Thus, the material should possess high strength, low density, damage tolerance [ 28 ], as well as processability. Such exceptional properties cannot always be found in solitary materials.…”

Progressive Damage Behaviour Analysis and Comparison with 2D/3D Hashin Failure Models on Carbon Fibre–Reinforced Aluminium Laminates

“…Tensile and bending tests are typical methods to evaluate the mechanical properties of composite structures [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. For example, Lu Yao et al [ 26 ] investigated the tensile behaviour of CARALL under various temperatures ranging from 25 °C to 175 °C, which combined experimental, theoretical, and numerical techniques.…”