Energy Absorbing Components Research Articles

Analysis of energy absorption characteristics of corrugated top beams of anti-impact hydraulic supports

To enhance the inferior energy-absorption performance of a hydraulic support during coal mine rock burst, which leads to failure and damage, a framework including a kind of corrugated laminated energy-absorbing component on the top beam of the hydraulic support is developed. First, triangular, trapezoidal and sinusoidal corrugated core energy-absorbing structures are designed, and their mathematical models are established. Second, three kinds of corrugated core components are optimized to obtain the suitable structural parameters, and based on the findings, the energy-absorption characteristic curves of the three kinds of corrugated core components are obtained through a simulation analysis. The results show that the sinusoidal corrugated core exhibits the best energy-absorption effect among the single-layer corrugated components. Among the two-layer and four-layer corrugated core components, the triangular corrugated core arrangement is the optimal arrangement. The energy absorption of the three kinds of corrugated core components is correlated with the delamination. The results of the experiment and simulation are consistent. This study provides a theoretical basis and experimental reference for the design of energy-absorbing components for an anti-impact hydraulic support.

Crashworthiness design and analysis for novel multi-corner square columns under axial loading

Due to the low manufacture cost and easy installation, tubal structures are common utilized as energy absorbers in automotive and other engineering industries. In the present work, four novel reinforced multi-corner columns (RMCs) were investigated using numerical, theoretical, and experimental approaches, results showed that the RMCs had prominent crushing performances compared with other typical multi-cell tubes. Furthermore, the TOPSIS method and multi-objective optimization were conducted to find the best structure and its optimal design parameters, respectively. The optimized column showed excellent crashworthiness capacities and had great potential to be used as energy-absorbing components in engineering applications.

Flexural and crashworthiness studies of friction stir welded aluminum alloy pipes

Friction stir welding (FSW), a solid-state joining process, is commonly used to join Aluminum alloys in aerospace, marine, car industry, and numerous industrial applications. Lightweight materials are commonly used in the transport industry to minimize component weight, and thin-walled structures are increasingly being used as energy-absorbing components in the industry. Even though FSW of plates is well established, FSW of pipe is still at the laboratory level. In this work, FSW for 6063 aluminum alloy pipe has been experimented through a novel procedure and it’s flexural and crashworthiness studies are carried out. The attempt of FSW is performed with a unique welding fixture mounted on a traditional milling machine. The crashworthiness test is conducted to analyze the ability of the structure to nullify the life loss during impact and the crash force efficiency of the pipe is identified. It is further analyzed for the flexural test to identify the bending load of welded aluminum alloy pipes. This study also exposes the basic understanding of the FSW procedure and its metallurgical implications of a friction stir welded pipe.

Front, rear and side impact analysis of backbone chassis of a compact sports car

The automotive chassis is the main load carrier and energy absorbing component in all crash events namely, frontal impacts, rear impacts, side impacts and roll over. It is important to have a strong and light weight material for the chassis. The purpose of this paper is to observe how a backbone chassis behaves during collision. This work involves static, dynamic and modal analysis of a backbone chassis of Lotus Europa, a compact sports car. Deformation, stress and strain distribution are evaluated and factor of safety is calculated using static structural analysis. In modal analysis mode shapes for different natural frequencies of the system are presented. Further, impact analysis performed using explicit dynamic analysis compares the deformation and stress distribution for front, rear and side impact for different impact velocities. Two materials namely mild steel and aluminium are compared for impact analysis.

Self-centering companion spines with friction spring dampers: Validation test and direct displacement-based design

This paper aims to propose self-centering companion spines with friction spring dampers (denoted as SCS) for obtaining better post-earthquake resilience in steel building structures. Two typical configurations of SCSs in buildings were first introduced. The SCS mainly consists of two rigid spines (RSs) and many friction spring dampers (FSDs). The two RSs have adequate strength and stiffness to create uniform inter-story drift distribution in SCS. The FSDs are the lateral force-resistant and energy-absorbing components and provide self-centering capacity for SCS. Some validation tests were further performed to investigate the hysteretic behavior of the developed SCS. Two different loading protocols were adopted in the experiments to test the stability of SCS subjected to different loading histories. 6% was set as the maximum loading roof drift to indicate the superior deformability of SCS. Moreover, three repeated loadings were performed for each loading protocol to study the behavior of SCS under aftershocks or multiple earthquakes. The experimental results show that the developed SCS can obtain stable and convincing self-centering hysteretic responses under repeated loading with different loading protocols, and no strength or stiffness deterioration can be found. These observations confirm that SCS is fully recoverable after earthquakes and has the potential to be used as a resilient seismic-resistant system in the building located in seismic regions. Lastly, the direct displacement-based design (DDBD) method was developed for SCS. A three-story SCS was designed on the basis of the proposed DDBD method. Nonlinear static and dynamic analyses were performed to validate the efficiency of the proposed DDBD procedure. The numerical results show that the designed SCS can show the anticipated nonlinear behavior and obtain the expected performance target.

Experimental and Numerical Study on the Energy Absorption of Polyurethane Foam-Filled Metal/Composite Hybrid Structures

Hybrid structures have the advantage of combining different types of materials at the same time. The trend of lightweight design in the transportation industry has promoted the development and application of composite materials with good crashworthiness performance. Low-density crushable foam-filled metal-composite hybrid structures have potential advantages as energy-absorbing components. This study investigated the mechanical characteristics of four different polyurethane foam-filled hybrid structures and their individual components under quasi-static axial compression. The experimental results showed foam-filled hybrid structures could change the deformation mode and improve stability during the compression process. Meanwhile, these hybrid structures could also improve energy absorption compared with their individual components. Among the different configurations, specimen C-PU-C (i.e., polyurethane foam filler between an outer CFRP tube and an inner CFRP tube) had the highest energy absorption capacity, at 5.4 kJ, and specific energy absorption, at 37.3 kJ/kg. Finally, a finite element (FE) model was established to analyze the mechanical characteristics of the hybrid structures by validating the simulation results against the experimental results.

Impact loading behavior of woven glass fabric polymer composite bi-tubular square sections

Glass fabric epoxy polymer composites are recognized as one of the efficient material for energy absorbing components, owing to their extremely dissipative crushing mechanisms involved during collisions. As a result, in addition to their light weight characteristics combined with attractive mechanical properties, they are employed in various domains such as automobile, railway, aerospace and marine industries etc. The present research paper aims to present the axial crashworthiness performance of thin-walled bi-tubular composite structures under impact load. The successfully manufactured composite bi-tubular components were imposed to axial impact loading with varied impact velocity of 8 m/s and 10 m/s. The SEA of eight layered glass fabric epoxy polymer composite square tubes are 5–35% significantly higher than the four layered glass fabric composite square tubes and can be used as a good alternative to the conventional single square tubes.

Experimental investigation into the bending energy absorption of hybrid aluminum/high strength and mild steel thin-walled sections joined by clinching

The employment of hybrid material thin-walled sections in the vehicle body structure is an emerging approach adopted towards manufacturing of lightweight energy-absorbing components in the automotive industry. Utilizing multi-materials such as aluminum-steel in the automotive industry poses some manufacturing challenges in terms of joining technologies of dissimilar materials. Clinching is a cold forming process that includes severe local plastic deformation of the sheets leading to permanent mechanical interlock. This study undertakes the experimental investigation of bending energy absorption of the clinched top-hat thin-walled beams by means of a series of quasi-static three-point bending tests. Different types of clinched beams including homogeneous as well as hybrid material beams, with aluminum alloy Al5052/SPCC mild steel and Al5052/SPFC 390 high strength steel combinations, are studied. The bending behavior of such beams under two different loading conditions is investigated and compared in terms of crashworthiness indices such as specific energy absorption ( SEA), initial peak force ( Fip) and crash force efficiency (CFE). It is found that although the hybrid clinched beams show higher SEA as well as lower Fip than their steel counterparts, their CFE values are lower than the steel beams. Furthermore, the sheets arrangement change with respect to the punch and the die is shown to influence the energy absorbing capability of the hybrid clinched beams. Moreover, it is revealed that while the clinched beams show reduced Fip under the load applied to their hat-shaped part, they exhibit lower CFE values compared to when the load is applied to their plate part. Finally, considering SEA, Fip, and CFE as three criteria, TOPSIS as a multi-criteria decision-making method is employed to select the best compromise design solution.

Axial compression deformability and energy absorption of hierarchical thermoplastic composite honeycomb graded structures

Thermoplastic composites have advantages of high damage tolerance, reprocessing and recycling capacities which are in growing demand in lightweight engineering applications. Structural gradient were introduced to designed continuous woven glass fiber reinforced hierarchical thermoplastic composite honeycomb graded structures (HTCHGS) aim to improve on deformation stability and induce the failure processes. Axial compression tests were conducted to investigate compression behavior, energy absorption capacity and influence of structural gradient distributions. Experimental observation showed that failure of HTCHGS was induced and constrained as expected, stable rising load plateau achieved by presented staggered conical HTCHGS. The staggered conical HTCHGS obtained mean value of 0.64 and 1.56 J/g on crushing force efficiency and specific energy absorption at the densification displacement. FEM simulations were carried out among presented configurations by parameterized modeling, validated the induced deformation processes by structural gradient which matched well with the tests. Stress distributions were compared among six configurations at typical deformation stage, found core components of staggered configurations contribute more to energy absorption than that of regular configurations. Staggered dumbbell HTCHGS provide long and stable deformation plateau till densification, and staggered conical HTCHGS are considered as optimal energy absorbing components among the configurations which give possible guidance for engineering structural designs.

Mechanical behavior and factors influencing axial splitting energy absorbers and optimized application for rock bolts

An axial splitting energy absorber for rock bolts was designed to adapt to the large deformation of surrounding rocks in deep roadways. This paper presents an experimental investigation of the mechanical behavior of the splitting energy absorbers with different parameters. The effects of materials, diameter-to-thickness ratio, prefabricated cuts, induced splitting dies, anti-curling splitting conditions, and oblique loading on the performance of the components were studied. The test results indicated that the splitting process of the component made of Q235 steel with four prefabricated cuts, is more stable; the smaller the diameter-to-thickness ratio, the higher the constant axial load level of the component; the anti-curling condition can only increase the load level of the components by 6%; the components have the advantages of “strong deformation sensitivity and weak load sensitivity” when subjected to oblique loading. Eventually, the parameters of the energy absorber were optimized for the rock bolts, i.e., the components have an inner diameter of 26 mm, a wall thickness of 4 mm, and four prefabricated cuts with a free-curling splitting mode. The novel anchor bolts exhibited stable energy absorption behaviors when subjected to static and dynamic loading. Moreover, the energy absorbers increased the stability, thereby yielding a rebar stroke of 40–200 mm. More importantly, serial research work on energy-absorbing components with various parameters will establish the experimental foundation for the application of components in various mining environments.

Crashworthy design and energy absorption mechanisms for helicopter structures: A systematic literature review

Helicopters are versatile aircraft that can perform numerous missions such as ground surveillance, rescue missions, air ambulance, fire-fighting etc. However, helicopter crashes sometimes occur owing to technical failures or human errors. Accordingly, the crashworthy design of helicopters has always remained a top priority to prevent catastrophic structural failure and significant casualties. The crashworthy performance of helicopters can be immensely improved with well-designed energy absorption materials or structures. This paper presents a systematic literature review on crashworthy design and energy absorption mechanisms for helicopter structures. Firstly, the historical development of aircraft crashworthiness investigation at various periods over the past few decades is presented. Then, some typical energy absorbing components such as rings, tubes, honeycombs, corrugated structures and emerging energy absorbers are introduced to act as the major structural elements for the crashworthy design of helicopters. After that, an emphasis is placed on the dynamic behavior and energy absorption of typical helicopter structures such as the landing gear, subfloor, full-scale airframe, helicopter crashworthy seats, fuel tank and helicopter blade. In addition, representative helicopter crash scenarios such as bird strike, water impact and the impact response and injury of the occupants are described. Finally, the crashworthy evaluation criteria of helicopter structures are summarized in this paper. This article is intended as a comprehensive literature review of crashworthy design and impact protection of helicopter structures.

Crashworthiness of tailored-property multi-cell tubular structures under axial crushing and lateral bending

Abstract Thin-walled structures have been widely used as energy-absorbing components, which can be probably subjected to multiple loading conditions in real life, such as axial crushing and lateral bending. Most of the existing literature solely focuses on the pure axial crushing or lateral bending. In this paper, a novel tailored-property multi-cell tubular structure is proposed, where the material's ultimate strength at the corner region is increased to accommodate both the axial crushing and lateral bending conditions. Finite element (FE) models were developed and validated through experimental results. The FE models were used to investigate the crashworthiness performances of the tailored-property multi-cell tubes under axial crushing and lateral bending. Under both axial crushing and lateral bending, it was found that the tailored-property multi-cell tubes exhibited noticeable advantages over the corresponding traditional tubes. The tailoring ratio and thickness had a significant influence on the crashworthiness performance of the tailored-property multi-cell tubes. Moreover, the well-designed tailored-property multi-cell tubes could exhibit the progressive deformation mode under axial crushing. Furthermore, a theoretical model for the tailored-property multi-cell tubes under axial crushing was developed based on the Superfolding Element (SFE) Method. The results showed that the theoretical solutions were in good agreement with the finite element analysis results. The findings of this paper have the potential for energy absorption applications under different loading conditions.

Characterization and Control of the Compromise Between Tensile Properties and Fracture Toughness in a Quenched and Partitioned Steel

The enhancement of the fracture toughness is essential for opening the possible range of applications of advanced high-strength steels, while the focus in the literature is primarily on the strength–ductility compromise. A high fracture toughness is indeed needed for energy absorbing components as well as to limit edge cracking sensitivity during part forming. This study investigates the tensile properties and the fracture toughness of various quenched and partitioned microstructures. The fracture resistance is evaluated using double-edge notched tension tests. While the uniform elongation continuously increases with the retained austenite (RA) fraction, the fracture toughness shows a maximum at intermediate RA content. For the highest amount of RA, the relatively low fracture toughness is mainly attributed to the formation of brittle necklace of fresh blocky martensite in the fracture process zone due to a high stress triaxiality, inducing an intergranular fracture mode. For intermediate RA fraction, the RA morphology evolves from blocky to film type, leading to a transition from intergranular to ductile fracture mode, and the RA-to-martensite transformation contributes to a higher total work of fracture compared to tempered martensitic steel. A proper control of both the amount and morphology of RA during microstructure design is thus essential to generate the best compromise between tensile properties and fracture toughness.

Impact Energy Absorbing System for Space Lander Using Hemispherical Open-Cell Porous Aluminum

Impact energy absorbing system for space lander is an important technology for space exploring missions. Open-cell porous aluminum manufactured through 3D selective laser melting process has been used on the energy absorbing system. Compression tests for cylindrical and hemispherical shaped porous aluminum with different porosities revealed the high potential as an energy absorbing component. It was found that the suitable heat treatment were effective to increase the energy absorbing potential of the porous aluminum.

Study of the energy absorption performance of an axial splitting component for anchor bolts under static loading

The large deformation characteristics of the surrounding rock of a high-stress mining roadway were studied during the period of frequent occurrences of micro-seismic events. Furthermore, axial splitting energy-absorbing components for anchor bolts were designed to allow anchor bolts to adapt to a large deformation of the surrounding rock in deep roadways and effectively prevent rock bursts. The application mode and working principle of the components of the anchor bolts were preliminarily studied. The mechanical properties and energy absorption effect of the components with different parameters under a quasi-static load in three test groups, namely, “28-2,” “26-3,” and “26-4,” were experimentally investigated. The results showed that the axial splitting component deformed stably, producing symmetrical strips with good repeatability and controllability. A constant axial load, ranging from 34.90 kN to 132.92 kN between different components in the tests, was observed with a long stroke after a short fluctuant load. The energy absorption performance of the specimens was assessed by calculating the energy absorption efficiency (EAE) and stroke efficiency (SE). The fluctuant axial load could be eliminated by preliminary treatment, improving the SE to approximately 90%. The effective splitting length of the component was emphasized as an important index to observe some dynamic supporting parameters in real time. The axial splitting component was demonstrated as an ideal energy absorber for energy-absorbing anchor bolts.

Crashworthiness multi-objective optimization of the thin-walled tubes under probabilistic 3D oblique load

In a real-world loading case (e.g., car crash accidents), energy-absorbing components are subject to oblique loads at various uncertain angles. This paper aims to investigate the behavior of such components under three-dimensional (3D) oblique loads in deterministic and probabilistic loading conditions. In this way, some square tubes are tested experimentally, and results are utilized to validate numerical models. To apply the 3D oblique load, a special test setup is designed, constructed, and installed on a universal tensile testing machine. Hammersley method is employed to design sample points. ABAQUS software is used for the finite element modeling and analysis. GEvoM software is implemented for mapping design variables onto crashworthiness characteristics including energy absorption (EA) and peak crush force (PCF). Both deterministic and reliability-based robust design (RBRD) optimizations are performed, and their results are compared with each other. The primary outcome of this research is the effect of incidence angles on the energy-absorbing characteristics, as well as some remarkable trade-off design points obtained from various multiple-criteria decision-making (MCDM) methods. It was discovered that the obtained design points of probabilistic study, which satisfied the reliability constraint, were roughly 60% more robust than deterministic points.

Parametric design strategy of a novel cylindrical negative Poisson’s ratio jounce bumper for ideal uniaxial compression load-displacement curve

A cylindrical negative Poisson’s ratio (CNPR) structure based on two-dimensional double-arrow negative Poisson’s ratio (NPR) structure was introduced in this paper. The CNPR structure has excellent stiffness, damping and energy absorption performances, and can be applied as spring, damper and energy absorbing components. In this study, the CNPR structure was used as a jounce bumper in vehicle suspension, and the load-displacement curve of NPR jounce bumper was discussed. Moreover, the influences of structural parameters and materials on the load-displacement curve of NPR jounce bumper were specifically researched. It came to the conclusion that only the numbers of cells and layers impact the hardening displacement of NPR jounce bumper. And all parameters significantly affect the structure stiffness at different displacement periods. On the other hand, the load-displacement curve of NPR jounce bumper should be in an ideal region which is difficult to be achieved applying mathematical optimization method. Therefore, a parametric design strategy of NPR jounce bumper was proposed according to the parametric analysis results. The design strategy had two main steps: design of hardening displacement and design of stiffness. The analysis results proved that the proposed method is reliable and is also meaningful for relevant structure design problem.

Quasi-static axial crushing behaviour and energy absorption of novel metal rope crochet-sintered mesh tubes

This paper presents a novel reinforcement structure for composite tubes, i.e. crochet-sintered mesh tube (CSMT), for energy absorption applications. The CSMTs are fabricated by crocheting, followed by swelling and vacuum solid-phase sintering of super-fine soft 304 stainless steel wire rope twisted with 49 steel wires. This study focuses on their quasi-static crushing response and energy absorption, and investigates the influence of tube diameter and length on these characteristics. Unlike the dense structure of thin-walled metal tubes used at present, the CSMTs have a special porous structure characterised by inter-crocheting and multiple inter-locking rope skeletons and metallurgical bonds. The crushing deformation exhibits progressive folding with collapse of the mesh pores and densification, without fracture under large plastic deformation, and with rope skeleton stretching, bending, twisting and warping. The diameter and length of the CSMTs have a significant effect on the crushing mode and stability. With the same length, the larger the diameter, the better is the stability; the larger the ESR (effective stroke ratio), the higher are the SEA (specific energy absorption) and CFE (crushing force efficiency). With the same diameter, the greater the length, the weaker is the stability; the smaller the ESR, the lower are the SEA and CFE. The CSMT3 with 40 mm length and 35 mm diameter shows the best deformation stability, an ESR of 0.59, and an SEA of 1114.7 J/kg. The CSMT5 with 65 mm length and 35 mm diameter presents the lowest ESR (0.44) and SEA (592.3 J/kg). The CFE values of all the CSMTs are very high and lie in the range of 0.7–1.0. There is no significant initial impact effect. The CSMTs’ lightweight, porous, and continuous wire structure, their long and stable plastic platform, and their collapsing deformation and high crushing force efficiency make them suitable for applications related to energy absorption components. The CSMTs may be used as a new reinforcement structure in composite tubes, and play an important role in the development of the novel structure of thin-walled metal tubes for energy absorbing components.

Crashworthiness of different composite tubes by experiments and simulations

Abstract Composite tubes show a good energy absorbing ability and they have great potential as energy absorbing components to replace traditional metal structures in automobiles, aircrafts and other transportation. This paper aims to investigate the impacts of geometrical parameters, including intermediate diameter, wall thickness and upper end diameter, on the specific energy absorption (SEA) of composite tubes, metal tubes, foam-filled tubes and hybrid tubes. The mechanical characteristics (axial compression response) of these tubes were numerically predicted by commercial finite element (FE) package LS-DYNA. Quasi-static axial compression tests were performed to determine failure parameters of glass fiber reinforced polymer (GFRP) used in this paper. Stress-strain curves of polyurethane foam and aluminum foam were also obtained by tests. Finite element models of hollow GFRP, aluminum and aluminum-FRP tubes and polyurethane foam-filled and aluminum foam-filled composite tubes were established respectively. Configurations of these numerical models include circular, square and tapered (5 different upper end diameters) tubes. In optimization part, structural parameters optimization was carried out by response surface method (RSM). Results review that in general, SEA of circular tubes increases with smaller diameter-thickness ratio. In comparison part, SEA of circular, square and tapered tubes were compared. Results show that changing upper end diameter of tubes has great impacts on their energy absorption capacity, but sensitivities of SEA to geometrical parameters and cross-section shapes differ depending on materials of tubes and foam filling.

A passive metallic damper with replaceable steel bar components for earthquake protection of structures

In this paper, a new passive earthquake damper termed as Bar-Fuse Damper (BFD) is presented for frame structures. The BFD is developed from common steel sections such as hot-rolled Square Hollow Sections (SHS), C-channels, plates and bars. It is economical, easy to install and build with no special fabrication technique. The key feature of the BFD is using round steel bars as energy absorber components that can be easily replaced in case of failure. The proposed device dissipates the energy with the replaceable bars as sacrificial elements through the flexural and tensile mechanism. The performance of several full-scale BFDs was evaluated with a series of monotonic and cyclic experiments, and the bars successfully performed their function as energy absorbers and fuses in all specimens. The effects of variations in the number, length and diameter of bars in the BFD along with the nuts arrangement were investigated in this experimental study. This study indicates that the recommended device has stable hysteretic behaviour under cyclic loads with two significant features: appropriate energy dissipation and replaceability of the fuses, which can be useful to protect the main elements of structures from plastic deformation and failure for several events. The results obtained for the BFD are promising for its use as a passive seismic damper in engineering structures in order to improve the seismic behaviour of structures as well as dissipating the earthquake energy.