Dynamic Axial Compression of Square CFRP/Aluminium Tubes

2019 ◽  
Vol 794 ◽  
pp. 202-207
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Jeong Whan Yoon ◽  
Zhan Yuan Gao

Carbon fibre composite tubes have high strength to weight ratios and outstanding performance under axial crushing. In this paper, square CFRP tubes and aluminium sheet-wrapped CFRP tubes were impacted by a drop mass to investigate the effect of loading velocity on the energy absorption of CFRP/aluminium tubes. A comparison of the quasi-static and dynamic crushing behaviours of tubes was made in terms of deformation mode, peak crushing force, mean crushing force, energy absorption and specific energy absorption. The influence of the number of aluminium layers that wrapped square CFRP tubes on the crushing performance of tubes under axial impact was also examined. Experimental results manifested similar deformation modes of tubes in both quasi-static and dynamic tests. The dynamic peak crushing force was higher than the quasi-static counterpart, while mean crushing force, energy absorption and specific energy absorption were lower in dynamic tests than those in quasi-static tests. The mean crushing force and energy absorption decreased with the crushing velocity and increased with the number of aluminium layers. The impact stroke (when the force starts to drop) decreased with the number of aluminium layers.

2016 ◽  
Vol 725 ◽  
pp. 82-87 ◽  
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu

In this study, hollow square carbon fibre reinforced plastic (CFRP) tubes and aluminium sheet wrapped CFRP tubes have been axially crushed at a quasi-static loading velocity of 0.05 mm/s. A specially designed and manufactured platen with four cutting blades was used to cut and crush these two tubular structures. The four cutting blades had height of 5 mm and width of 3 mm with round tip to reduce the initial peak force and achieve a stable crushing deformation mode. Notches at one end of each tube were utilized to control the location of initial failure. The crashworthiness characteristics of hollow CFRP tubes and aluminium sheet wrapped CFRP tubes with notches that crushed by the platen with cutting blades were compared with those of tubes that crushed by a flat platen. Experimental results showed that using the platen with blades to crush the specimens with notches exhibited more stable deformation mode than the specimens without notches. Mean crushing force, energy absorption and specific energy absorption (SEA) increased when CFRP was wrapped with aluminium sheet and crushed by the platen with blades. The increase of average value of mean crushing force, energy absorption and specific energy absorption of aluminium sheet wrapped CFRP tube and crushed by the platen with blades are 16.5%, 17.3% and 5% respectively more than those for hollow tubes that crushed by a flat platen.


2020 ◽  
Vol 991 ◽  
pp. 62-69
Author(s):  
Sallehan Ismail ◽  
Mohamad Asri Abd Hamid ◽  
Zaiton Yaacob

This study aims to investigate the dynamic behavior of recycled mortar under impact loading using a split Hopkinson pressure bar (SHPB). Several mortar mixtures were produced by adding various fine recycled aggregates (FRA) to the mixture in replacement percentages of 0%, 25%, 50%, 75%, and 100% of the natural fine aggregate (NFA). The effects of strain rate on compressive strength and specific energy absorption were obtained. Results show that the dynamic compressive strength and specific energy absorption of recycled mortar are highly strain rate dependent; specifically, they increase nearly linearly with the increase in peak strain rate. However, the compressive strength and specific energy absorption of recycled mortar are generally lower than those of NFA mortar (reference samples) under similar high strain rates. The findings of this research can help researchers and construction practitioners to ascertain the appropriate mix design procedure to optimize the impact strength properties of recycled mortar for protective structural application.


2017 ◽  
Vol 744 ◽  
pp. 317-321 ◽  
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Akshay Kumar

The aim of this study is to find the best platen with blades as a new energy dissipating mechanism that causes considerably damage to CFRP/aluminium tubes. Specially designed and manufactured platens with five different cutting blade profiles were used to simultaneously cut and crush square CFRP tubes and aluminium sheet-wrapped CFRP tubes. The platens with blades were evaluated in terms of the deformation mode, mean crushing force, energy absorption and specific energy absorption of tubes. Experimental results showed that tubes cut and crushed by the platen with 45o inclined blades had the best crushing performance and exhibited a more stable deformation mode compared with those for tubes cut and crushed by other platens with different blade profiles. The platens with blades acted as trigger mechanisms that minimise the initial peak crushing force and maximise the energy absorption of tubes compared with tubes crushed by flat loading platens.


In vehicle design, safety of occupants is one of the most important criteria. During side collisions, space between vehicle body and occupants is very less as compared to frontal collision. Hence, scope for energy absorption due to deformation of vehicle body in side collisions is less. The strength of side door plays important role in the framework of vehicle side body. The strength of side doors during side collision depends upon the impact beam, vehicle construction, layout of doors etc. Among the mentioned parameters, strength of impact beam is a crucial parameter. The impact beam absorbs notable amount of impact energy by deforming during side collision. Design of side impact beam should be optimum as it is limited by weight of vehicle. Parameters like material, dimensions, shape and mountings of beam inside the door are affecting the strength of side impact beam. In this work parameters of circular cross-section impact beam like diameter of beam, thickness of beam and angle of mounting inside the door are studied. Finite element simulation of side impact beam is done in ABAQUS software and its relative effects on Specific Energy Absorption (SEA) capacity of beam is studied. The simulation results are validated with available literatures. The ANOVA analysis followed by Design of Experiments is used to determine contribution of each parameter on SEA. Further various parameters of circular impact beam are studied by examining the result analysis for crashworthiness of side door.


Author(s):  
A Praveen Kumar

In recent years, aluminium-composite hybrid tubular structures, which combine the stable and progressive plastic deformation of the aluminium metal with light-weight composite materials, are obtaining increased consideration for meeting the advanced needs of crashworthiness characteristics. This research article presents the experimental outcomes of novel aluminium/composite-capped cylindrical tubes subjected to quasi-static and impact axial loads. The influence of various capped geometries in the aluminium segment and three different fabrics of the composite segment in the cylindrical tube are investigated experimentally. The outcomes of the impact crushing test are also correlated with the quasi-static results of the proposed aluminium/composite-capped cylindrical tubes. The overall outcomes revealed that the crashworthiness characteristics of crushing force consistency and specific energy absorption of the aluminium-composite hybrid tubes are superior to those of the bare aluminium tubes. When the glass fabric/epoxy composite is wrapped to aluminium cylindrical tubes, the specific energy absorption increases about 23–30%, and the wrapping of hybrid glass/kenaf fabrics increases the specific energy absorption of almost 40–52%. Such a hybrid tubular structures would be of huge prospective to be used as effective energy-absorbing devices in aerospace and automotive applications. A further benefit of the composite-wrapping approach is that the composite might be retro-fitted to aluminium tubes, and the energy absorption capability is shown to be significantly enhanced by such utilization.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5985-6002
Author(s):  
Peng Cheng ◽  
Qingchun Wang ◽  
Shi Ke

The specific energy absorption of a thin-walled tube can be improved by filler. This study examined the potential use of a cheaper biomass filler, paper scraps, to enhance the energy absorption characteristics of the structure while reducing its cost, compared to that with a traditional filler such as foam material. Quasi-static crushing tests and finite element simulations were performed by using the explicit non-linear finite element software LS-DYNA to determine the improvements to the mean crushing force and specific energy absorption of the steel tube when filled with different densities of paper scraps. The mean crushing force and specific energy absorption of the empty tube, the paper scraps, and thin-walled tube filled with paper scraps were determined, and corresponding numerical simulations were performed. The simulation and test results showed that the impact performance of tube filled with paper scraps was greatly improved when paper scraps density was 0.35 g/cm3. By optimizing paper scraps filling structure, a new structure that could further enhance the specific energy absorption was obtained. The optimal scheme could increase the specific energy absorption of Q345 steel tube by 11.35%.


Author(s):  
Qiang Gao ◽  
Liangmo Wang ◽  
Yuanlong Wang ◽  
Chenzhi Wang

All types of thin-walled tube with different configurations were studied to determine their crashworthiness performances. A novel single-cell tapered elliptical tube is proposed in this paper. First, the crashworthiness performance of the single-cell tapered elliptical tube subjected to different oblique impacts was compared with those of other tubes with different configurations (straight, tapered, and multi-cell tapered) and different cross-sections (square, rectangular, and circular). It can be found that the single-cell tapered elliptical tube shows a better crashworthiness performance at multiple loading angles by comparing the specific energy absorption values and minimizing the peak crushing force. Second, to simplify the optimization process, the radial basis function model combined with the design-of-experiments method was utilized. Third, to determine the ideal radial rate f, the taper angle θ and the thickness t of the wall of the single-cell tapered elliptical tube, this paper adopted the non-dominated sorting genetic algorithm II to maximize the specific energy absorption and to minimize the peak crushing force. When determining the effect of the uncertainty in the loading angle, two different weighting-factor cases (case 1 and case 2) can be considered. In both cases, the optimized single-cell tapered elliptical tube has a better crashworthiness performance than tubes with other different cross-sections do. The design has a great influence on the optimization results. In comparison with the original single-cell tapered elliptical tube, in case 1, the composite specific energy absorption index under multiple oblique loading of the optimal tube increases by 12.81% and the peak crushing force at 0° decreases by 16.66% and, in case 2, the specific energy absorption index under multiple oblique loading increases by 11.8% and the peak crushing force at 0° decreases by 12.83%.


2018 ◽  
Vol 22 (8) ◽  
pp. 2735-2767
Author(s):  
Ali Bigdeli ◽  
Mohammad Damghani Nouri

In this study, aluminum thin-walled cylindrical absorbers for crashworthiness are investigated to introduce a novel system with better energy absorption and crushing characteristics under quasi-static axial compressive loading. The inside of the thin-walled cylinders is meshed with a square welded from vertices to the thin-walled cylinder. Here, the response surface method, which is one of the design of experiments techniques has been used to examine the effect of the parameters on energy absorption, initial peak crushing force, specific energy absorption per unit mass and energy absorption per length. The variables of thickness (t), height (h) and length of square (l) of the thin-walled cylinder were considered in three levels and initial peak crushing force, specific energy absorption per unit mass and energy absorption per length were selected as response. The specimens were analyzed under a quasi-static compressive test at a constant speed of 10 mm/min. Subsequently, for further investigation, the experimental results were compared with those obtained from the finite element simulation using Abaqus software, which indicated desirable accuracy. To decrease the solution time in this numerical analysis, the speed was set at 0.5 m/s. Finally, the experimental results were compared with the simulation ones, which showed acceptable compatibility. Further, there are the equations obtained from the multi-objective optimization testing design. The results indicated a linear relationship of thickness with responses, nonlinear relationship of height with responses, linear relationship of length of square with initial peak crushing force, and nonlinear relationship with specific energy absorption per unit mass and energy absorption per length.


2014 ◽  
Vol 23 (2) ◽  
pp. 096369351402300
Author(s):  
Ping Zhang ◽  
Liang-Jin Gui ◽  
Zi-Jie Fan ◽  
Jing-Yu Liu

This paper presented an experimental study on the low-velocity impact response of triaxial braided composite circular tubes, which were fabricated with S-glass/epoxy composite. The impact responses were recorded and analyzed in terms of impact load-displacement curves and specific energy absorption. In addition, four basic failure modes called delaminating, splaying, fragmental fracture and progressive folding were founded. The levels of the mean impact load and specific energy absorption (SEA) are determined by the energy absorption mechanisms, which are related to the dominant failure modes of the tubes. In general, delamination which exhibits the poor energy absorbing performance is the dominant failure mode for all the specimens. Impact test results showed that all three types of tubes had almost the same SEA. Compared to the quasi-static test results, the first peak load and the mean load decrease at about 50% and 10% respectively, SEA generally decreases at an average level 10%.


2020 ◽  
Vol 54 (27) ◽  
pp. 4253-4268
Author(s):  
Mou Haolei ◽  
Xie Jiang ◽  
Zou Jun ◽  
Feng Zhenyu

To research the failure of carbon fiber-reinforced composite laminated specimens, the tensile tests and compressive tests were conducted for [90]16 and [0]16 specimens, and the shear tests were conducted for [±45]4s specimens, and the microscopic failure mechanisms were observed by scanning electron microscopy. To research the failure and energy absorption of different thin-walled structures with different layups, the quasi-static axial crushing tests were conducted for [±45/0/0/90/0]s and [0/90]3s circular tubes, [0/90]3s and [±45]3s square tubes, [0/90]4s and [±45]4s sinusoidal specimens, and the internal failure were further investigated by 3D X-ray scan. Based on the load-displacement curves, the energy absorptions were evaluated and compared according to specific energy absorption and peak crushing force, and the relationships between failure modes and specific energy absorption, peak crushing force were further researched. The results show that the macroscopic failure modes are the collective results of varieties of microscopic failure mechanisms, such as fiber fracture, matrix deformation and cracking, interlamination and intralamination cracks, cracks propagation, etc. The [±45/0/0/90/0]s circular tube shows the transverse shearing failure mode with high specific energy absorption. The [±45]3s square tube and [±45]3s sinusoidal specimen show the local buckling failure mode with low specific energy absorption. The [0/90]4s sinusoidal specimen, [0/90]3s circular tube, and [0/90]3s square tube show the lamina bending failure mode with medium specific energy absorption. The failure mode of thin-walled structure can be changed by reasonable layups design, and the energy absorption can further be improved.


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