Energy Absorption Of Composite Structures Research Articles

Energy absorption characteristics of a bio-inspired prepreg carbon fiber crash box under quasi-static axial compression

Reducing vehicle weight is crucial for enhancing fuel efficiency and reducing emissions in transportation. Traditional composite materials offer improved energy absorption over metals yet are limited by brittleness. This study introduces an innovative approach, inspired by the mantis shrimp's natural defense mechanisms, to enhance the crashworthiness and energy absorption of composite structures, optimizing safety and performance. Utilizing a bio-inspired design, we developed corrugated Carbon Fiber Reinforced Polymer (CFRP) crash box structures, aiming to optimize their energy absorption capabilities and crash force efficiency (CFE) for potential applications in transportation safety. Through a series of quasi-static axial compression tests, the corrugated structures' performance was evaluated against traditional crash box designs. The experimental results demonstrate that the bio-inspired configurations improved crashworthiness characteristics. Strategic manipulation of layer numbers and corrugations led to superior CFE values, indicative of safer, more controlled collision behavior. The “7N-6L” configuration featuring seven corrugations with six layers of CFRP demonstrated the highest efficacy, achieving an optimal CFE of 1.08. This configuration demonstrated a Specific Energy Absorption (SEA) of 1.56 J/g and an Energy Absorption (Ea) of 42.56 J. Furthermore, compared to conventional steel crash boxes, the CFRP crash box with 7N-6L corrugated structure showcased competitive energy absorption capabilities with significantly reduced mass, absorbing 2850 J with a CFE of 0.91, nearly matching the ideal CFE and highlighting its superior lightweight performance. These results underline the potential of integrating bio-inspired designs to develop robust, lightweight structures for improved crashworthiness, paving the way for safer and more sustainable transportation solutions.

Energy absorption in composite structure reinforced with advanced functionally graded nano-materials: Artificial intelligence and numerical approaches

The energy absorption characteristics of materials and structures are crucial for ensuring the safety of structures when subjected to mechanical forces. This study focuses on the significance of energy absorption in composite structures. Specifically, it examines the energy absorption in composite structures that are reinforced using sophisticated functionally graded nano-materials. The analysis is conducted using both mathematical modeling and artificial intelligence methods. The Halpin–Tsai micromechanics method is employed to simulate the material properties of the advanced composite construction, taking into account the role of the mixture. Within the realm of mathematical modeling, the energy method, higher-order Taylor’s Formula, Viscoelastic formula, and differential quadrature method (DQM) are employed to extract and solve the governing equations of composite structures reinforced with advanced functionally graded nano-materials. The Deep Neural Networks Model (DNNM) is a highly popular supervised machine learning approach that may be employed for both regression and classification tasks. The objective of regression analysis is to determine the correlation between independent variables and dependent responses by identifying the function of optimal decision that can accurately explain the fluctuations in the response parameter depending on the dependent variables. In the second phase, the findings acquired from mathematical modeling are trained and evaluated for the aim of DNNM. Upon receiving the results, recommendations for enhancing the energy absorption in composite structures reinforced with advanced functionally graded nano-materials will be provided for inclusion in future publications on advanced structures.

Study of magnetorheological fluids towards smart energy absorption of composite structures for crashworthiness

ABSTRACTA study of magnetorheological fluids energy absorption capability towards development of composite retrofit technologies for aged helicopters is presented in this article. Design parameters that influence the performance of magnetorheological dampers were identified and evaluated based on the damping force as a measure of compatibility to energy absorption. Tensile, compression, and cyclic loading tests were also conducted experimentally to validate the numerical investigation. An extensive parametric study conveyed that the piston head radius plays a major role in achieving higher damping force. The fundamental behaviors and results of the damping force in the numerical studies were also in a good agreement with the experimental results. The novel parametric numerical analysis framework validated in this article will allow for efficient design and optimization of future dampers.Received 2 August 2013 Accepted 9 January 2015

A Coupled Damage-plasticity Model for Energy Absorption in Composite

Predicting the energy absorption of composite structures requires a constitutive model that is capable of representing post-peak softening and irreversible strains, i.e., a coupled damage-plasticity model. The development of such models requires a general damage-plasticity framework. This article examines the merits and limitations of the continuum damage mechanics (CDM) framework and the plasticity framework. Based on the physical evidence of damage accumulation process in composites and the fundamentals of the two theories, a simple coupling method was proposed. This method employs a perfect plastic flow rule within a CDM framework. The capability of this method was examined by incorporating plasticity into the Matzenmiller-Lubliner-Taylor (MLT) model, a classic CDM model for composites. The coupled MLT-plasticity model was implemented as a user defined material law in explicit finite element code LS-DYNA®, and subsequently numerical tests were conducted. It was demonstrated that the proposed method can extend an existing composite CDM model into a coupled damage-plasticity model seamlessly with only a few extra parameters, while retaining its computational efficiency. The capability of the coupled CDM-plasticity model in energy absorption prediction was validated in axial impact simulations of a composite tube reinforced with 1-ply carbon fiber tri-axial braid.

Modeling Energy Absorption with a Damage Mechanics Based Composite Material Model

The Matzenmiller—Lubliner—Taylor (MLT) model, a continuum damage mechanics (CDM) based model, was used in modeling energy absorption of composite structures in crashworthiness applications. It was found that the assumption of linear elastic unloading and reloading in MLT model resulted in a lower calculated energy absorption in thin wall composite tube axial crush simulations. A modification to compressive unloading was proposed and tested in an MLT-based user material model. The modified model improved the stability of the tube crush simulation and the simulation results. This study demonstrates the importance of properly representing the unloading response of damaged composites in energy absorption prediction.

Dynamic characterization of structures: A study of energy absorption in composite tubes

In this article, we present a study of the parameters which affect energy absorption in composite structures under dynamic loading conditions and a description of an experimental direct-impact device for the study of such structures. To reduce the field of our investigations, we have limited ourselves to the study of cylindrical tubular structures. The different results show a variation of the specific energy of the composite tubes according to the nature of the fibres, the matrix, the stacking sequence and the loading speed. The strain rate, ge, is a parameter on which various studies have been published and for which conclusions are sometimes still opposed. To satisfy mechanical strengthening and weight problems, multimaterial metal-composite structures have been developed. The results obtained show that, during dynamic tests, some structures exhibit crushing processes leading to significant increases in the specific energies.

The Energy Absorption of Composite Plates under Off-Axis Loads

A fixture for measuring the energy absorption of composite structures under off-axis loads is developed. The testing fixture stabilizes the specimens by providing simply-supported boundary conditions on the sides of the specimen to prevent global buckling. Using the fixture, graphite/epoxy plates are crushed edgewise against an adjustable inclined plane surface and the energy absorbency is measured. Consistent test data are obtained that are similar to those obtained using different specimen geometries, indicating the acceptability of the test method. Results suggest that the off-axis crushing response may be described by considering the occurrence of a failure mode separately from the quantitative performance of the mode. Under off-axis loads, the energy absorbency of a specimen is dependent upon the failure mode experienced, but not directly on the orientation of the applied load. However, load orientation affected the preferred failure mode.

Relation of energy absorption of composite structures to material strength

The crushing of (±θ) filament-wound glass-epoxy composites tubes was studied both experimentally and theoretically. An analytical model was developed, which describes the interaction between the geometry and material properties which occurs during crushing. The study was based on a semi-empirical approach of the crushing process and used interlaminar crack propagation and material failure criteria. Quantitative results were obtained concerning the crushzone morphology and the influence of geometry and material strength on the energy absorption capacity of composite tubes. Good agreement with experimental data was obtained. Ways to establish a complete predictive model are discussed.

The Effect of Side Loads on the Energy Absorption of Composite Structures

Slightly tapered truncated cones were manufactured from graphite/epoxy preimpregnated unidirectional tape and were loaded in compression. Different amounts of side loads were introduced by orienting the loading axis away from the central axis of the cone. The cones were crushed under quasi-static conditions, and their energy absorption was measured. For small amounts of side load, the energy absorbency was improved; however, as the amount of side load is increased further, the energy absorption capability of the structure is reduced significantly. Furthermore, a tendency for the specimen to topple is observed as a result of the moment induced by the side loads which reduces the energy absorption properties even further.