Crushing behavior optimization of octagonal lattice‐structured thin‐walled <scp>3D</scp> printed carbon fiber reinforced <scp>PETG</scp> (<scp>CF</scp>/<scp>PETG</scp>) composite tubes under axial loading

This study presents a novel variable thickness nested tube consisting of circular tube and origami tube (VTCO) designed to reduce the initial peak crushing force (PCF) under axial loading while maintaining high energy absorption. The core of this design is to achieve progressive and controlled energy absorption and to reduce peak forces as well as accelerations that can lead to passenger injuries. Nested tube structures were fabricated using short carbon fiber‐reinforced nylon composites through 3D printing technology, and quasi‐static axial compression tests were performed. The results show that equal‐thickness nested tubes consisting of circular tubes and origami tubes (ETCO) perform better in terms of energy absorption and deformation stability compared to circular and origami tubes individually. The further improved VTCO reduced the PCF by 53% and significantly improved the crash force efficiency (CFE) by 54%. The VTCO structure was parametrically investigated by means of a validated finite element model and optimized using the Non‐Symmetric Dominance Sorting Genetic Algorithm II (NSGA‐II). The optimization results provide a feasible way to adjust the structural crashworthiness to meet different engineering requirements. This study provides valuable insights into the energy‐absorbing properties of VTCO structures and is an important guide for the application and material development of novel VTCO structures.Highlights ETCO offers better energy absorption and stability than circular and origami tubes individually. VTCO is superior to ETCO in reducing PCF and increasing CFE. Multi‐objective optimization using NSGA‐II to balance conflicting crashworthiness indicators.

Crashworthiness design and multi‐objective optimization of 3D‐printed carbon fiber‐reinforced nylon nested tubes

Jiang,

Zhao,

Xing

et al. 2024

Mechanical characterization of a 3D printed lattice core sandwich structure

Fareed,

Wu,

Sood

2024

Sandwich structures have garnered interest as versatile structures for applications in advanced engineering structures. To fabricate sandwich structures, plastics have replaced conventional materials; however, most of these plastics remain in the environment beyond their functional lifespan. This study describes the fabrication of sustainable hybrid sandwich structures with 3D printed poly‐lactic acid (PLA) cores and self‐reinforced polyethylene terephthalate (srPET) face sheets. The mechanical responses of the hybrid sandwich structures with three types of lattice cores, S‐90, S‐45, and S‐V, were compared with those of the parent material sandwich structures after performing bending and impact tests. The face sheet in the hybrid sandwich structure transferred the load to the core without failure. The hybrid sandwich structure containing the S‐90 core exhibited a higher fracture strength (52.4 MPa) and tangent modulus of elasticity (2860 MPa) than those of the other structures. S‐V exhibited the highest fracture strains of 3.3% and 5% for parent material and hybrid sandwich structures, respectively. This study highlights the sandwich structures with excellent mechanical properties for structural applications.Highlights Novel sandwich structures with 3D printed PLA cores are fabricated. Three‐point bending and low‐velocity impact tests are performed. Failure occurred in the core, but the Sr‐PET face sheets did not deform. Hybrid sandwich structures significantly improve mechanical performance.

Evaluation of crush and energy absorption characteristics of corrugated origami tube by additive manufacturing

Sun,

Jiang,

Zhao

et al. 2024

Origami tube (OT) has attracted significant attention in the realm of thin‐walled structures owing to their remarkable energy‐absorption capabilities. Nevertheless, their deformation modes, particularly buckling, present considerable stability challenges. In this research, we introduce a novel corrugated structure to enhance the energy absorption and stabilize the deformation mode of OT. The corrugated origami tube (COT) was manufactured using high‐specific modulus, high‐strength, and lightweight short carbon fiber‐reinforced nylon via 3D printing, followed by axial quasi‐static compression tests. The findings demonstrate that the incorporation of corrugations in COT greatly stabilizes tube deformation, boosting energy absorption by 21.3% compared to OT and reducing the peak crashworthiness force by up to 21.37%. Finite element analysis accurately replicates the experimental performance of the COT, affirming the feasibility of the simulation. Optimization using the Non‐dominated Sorting Genetic Algorithm II (NSGA‐II) produced a Pareto front, revealing trade‐offs among various crashworthiness indicators and offering a flexible design approach to meet diverse requirements. This study provides valuable insights and guidance for the design of lightweight, thin‐walled structures.Highlights The corrugated structure effectively stabilizes deformation mode of the OT. COT significantly improves energy absorption and reduces initial peak force compared to OT. The approach of multi‐objective optimization provides a variety of solutions for different needs.