Axial Crushing Behavior Research Articles

Effects of Temperature on Axial Crushing Behavior of Circular Multi-Walled Tubes

In this work, the impact of temperature on the crushing performance of multi-walled tube (MWT) were investigated using a combined experimental, theoretical and numerical method. The MWT was fabricated using extrusion technology, and the temperature-dependent axial crushing experiment was performed on a hydraulic testing machine. The results show that the peak crushing force (PCF), the mean force (Pm) and the specific energy absorption (SEA) decreased near-linearly by 21.7%, 30.7% and 30.7% as the temperature increased from 25 °C to 250 °C, while the crushing load efficiency (CLE) was insensitive to temperature. The average forces obtained via numerical prediction, theoretical analysis and experimental testing were basically consistent. The numerical results indicate that varied temperature alters the number of dominant wavelets and the relative lateral deflections of MWT. In addition, compared with the competitive structures, the energy absorption property of MWT is excellent at high temperatures.

Numerical simulation of the crush behavior of tapered tubes

Abstract Traffic accidents are increasing as a result of an increasing number of vehicles and population growth in recent years. Active and passive safety systems are used in the vehicles we use today to reduce traffic accidents and prevent casualties. One of the passive security systems is the crush box (crashworthiness). It absorbs the energy generated during a crash by plastic deformation. In this study, tube height, diameter and thickness parameters were kept constant and degrees of conicity were varied 0°(flat tube),3°,7°,10°,12° and 15° The effects of conical crush boxes on axial crush behavior and their energy absorption ability, were investigated by Ls-Dyna explicit dynamic software.

Numerical simulation of the crush behavior of tapered tubes

Abstract Traffic accidents are increasing as a result of an increasing number of vehicles and population growth in recent years. Active and passive safety systems are used in the vehicles we use today to reduce traffic accidents and prevent casualties. One of the passive security systems is the crush box (crashworthiness). It absorbs the energy generated during a crash by plastic deformation. In this study, tube height, diameter and thickness parameters were kept constant and degrees of conicity were varied 0°(flat tube),3°,7°,10°,12° and 15° The effects of conical crush boxes on axial crush behavior and their energy absorption ability, were investigated by Ls-Dyna explicit dynamic software.

A Novel Theoretical Approach for Estimation of Axial Crushing Behavior of Polygonal Hollow Sections

The aim of the present study was to introduce new crushing mechanisms in terms of crushing modes for estimating the crushing force and absorbed energy of polygonal thin walled metal sections subjected to axial progressive collapse. For this purpose, two models were developed. The first model, which has been extensively used before and named as “plastic hinge model” (PHM), was modified based on new crushing modes; and as the second, a novel model was introduced by the authors named as “induced curvature model” (ICM). The latter model was considered to be more realistic than the former due to consideration of metal sheet curvatures during progressive folding process, as well as including the hardening effect of the material during plastic deformation. All possible crushing modes for a typical polygonal section were considered and discussed by combining different crushing modes of the corner elements. New expressions for the absorbed energies and crushing force were presented based on the resulting crushing modes. To evaluate the validity and efficiency of the proposed models, a detailed FE simulation was conducted using LS-DYNA. Comparison of FEM, PHM and ICM results showed the superiority of the ICM over PHM.

Axial Crushing Behavior of Braided Carbon/Polyurethane Composite Tubes

A composite material consisting of carbon fiber fabric and polyurethane resin was used to fabricate circular tubes by resin transfer molding. The composite tubes were tested under both axial static compression and axial impact. To establish delamination criterion for this composite material, short-beam tests and curved-beam tests were executed, and it was verified by step cantilever-beam tests. The short-beam and curved-beam tests indicate that the interlaminar shear and tensile strengths of the composite are around 54.0 MPa and 8.8 MPa, respectively. Also the established delamination criterion has nice prediction for the delamination of the step cantilever-beam test. In addition to the delamination criterion, the finite element analysis with progressive failure was applied and could predict agreeable values on the total absorbed energy and the specific energy absorption of the braided composite tube under both the static and dynamic tests. These indicate that the present analysis could catch the axial crushing behavior of the braided composite tubes.

A computational mechanics engineering framework for predicting the axial crush response of Aluminum extrusions

Automakers are developing new lightweight aluminum alloys for automotive structures to reduce vehicle weight. However, these alloys require extensive mechanical characterization for accurate calibration of a numerical model, which is often a painstaking task. Automakers are exploring alternative strategies to reduce the number of experiments required for characterizing these new alloys without sacrificing accuracy in predicting performance. The method of virtual experimentation through computational mechanics engineering (CME) with crystal plasticity is showing promise in satisfying this need. This work presents a CME framework for predicting the axial crush behavior of an aluminum alloy AA6060-T6 extrusion using only a single uniaxial stress-strain response and 2D electron backscatter diffraction (EBSD) scans. An anisotropic phenomenological model is generated using a 3D reconstructed microstructure and a calibrated crystal plasticity model. Additional mechanical characterization is performed to qualify the proposed CME framework. Finite element simulations that employ the CME framework are performed to evaluate the suitability of this methodology in quasi-static axial crush applications. Quasi-static axial crush experiments of the extrusion are performed to validate the finite element simulations and the CME framework. Simulations using the CME framework were capable of predicting the experimental crush response with 3–4%. The proposed CME framework can help automakers reduce the number of experiments needed for the development of components in large deformation, such as crush.

Axial crush behavior and energy absorption capability of foam-filled GFRP tubes under elevated and high temperatures

Foam-filled circular composite tube has been widely used in safety design of automobile, space craft recovery and so on due to its advantage of high energy absorption, light weight and anti-corrosion. But the axial crush behavior and energy absorption capability of foam-filled composite tubes are threatened by elevated and high temperatures. In practice, the effects of high temperatures cannot be ignored because composites and foam are sensitive to temperature. In this paper, an experimental investigation was carried out to evaluate the effectiveness of energy absorption of foam-filled circular glass fiber reinforced plastic (GFRP) tube under elevated and high temperatures. The temperature range was from 20°C to 110°C, covered the glass transition temperature (92°C). In the meantime, the effects of high environmental temperatures on failure mode, crush force efficiency, energy ductility coefficient and specific energy absorption were also studied. The test results demonstrated that the axial crush behavior and energy absorption capacity of foam-filled GFRP tubes were determined by the environmental temperature. The foam-filled GFRP tubes can achieve top crashworthiness performance when the environmental temperature was less than 70°C.

Experimental and Numerical Study on the Axial Crushing Behavior of Textile‐Reinforced Thermoplastic Composite Tubes

Thermoplastic composites with excellent specific mechanical properties are well suited for the development and design of material‐ and energy‐efficient lightweight structures. In this work, the structural response of glass–polypropylene (GF/PP) hybrid yarn‐based composite tubes under quasi‐static and high‐velocity axial crushing has been investigated experimentally and numerically. Very promising crush responses can be identified in terms of peak crushing force, stable progressive crushing, and specific energy absorption. For the numerical simulation on mesoscale, a user‐defined material is used to predict the response of the textile‐reinforced plies. Delamination phenomena are modeled via a cohesive approach. The chamfer trigger is modeled in detail to ensure a stable progressive crushing.

Axial Crushing Behavior of Aluminum Square Tube with Origami Pattern

<span style="font-size: 10pt; font-family: 'Times New Roman','serif'; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US">The study of axial crushing behavior is important in designing crashworthy structures especially in automotive applications. The axial crushing of thin-walled tube has better energy absorption capability. Thus, introducing milled geometrical shapes on thin-walled tube may improve the energy absorption performance. The improvement of the crush response is determined through the reduction of the Initial Peak Force (IPF) and the increase of the Specific Energy Absorption (SEA). This was done by employing origami pattern milled on the surface of thin-walled square tube which was investigated experimentally and numerically. The material used for the tube was aluminum alloy 6063-T5. The simulation results were validated by experiments which were conducted using <span style="text-transform: uppercase;">Instron</span> 3382 Universal Testing Machine and <span style="text-transform: uppercase;">Instron Dynatup</span> 8250 Drop Hammer Machine. The numerical simulation then progressed by varying parameters such as dimensions and configurations of the origami pattern on the square tube. ABAQUS finite element (FE) software was used to conduct the numerical simulation. The result of employing the origami square pattern on square tube is expected to improve the crush response by lowering the IPF and increasing the SEA. The obtained results were then compared with the conventional square tube where the origami pattern on square tube enhanced the crush performance.</span>

Quasi-static Axial Crushing Behavior of Thin-walled Circular Aluminum Tubes with Functionally Graded Thickness

In this paper, the crushing behavior of circular aluminum thin-walled tubes with functionally graded thickness (FGT) are investigated experimentally. To this aim, three different thickness grading patterns are introduced to the longitudinal direction of tubes using a grading function, and then specimens are tested by universal testing machine under quasi-static axial compression loading. In addition, to show the efficiency of FGT tubes, the quasi-static axial crushing performance of FGT tubes are compared with their uniform thickness (UT) counterparts at the same weight. The test specimens have been made of commercial quality 6060 aluminum alloy and manufactured with computerized numerical controlled (CNC) machining workbench. Initial crush force (ICF), total energy absorption (EA), specific energy absorption (SEA) and mean crush force (MCF) values are measured from the tests to infer the quasi-static axial crushing performance of the tubes. The test results showed that the energy absorption characteristics of FGT tubes are better than the UT counterparts and FGT tubes allow effective control of the energy absorption parameters when compared with the UT tubes due to their varying stiffness along their longitudinal direction.

Axial crush behavior and energy absorption capability of foam-filled GFRP tubes manufactured through vacuum assisted resin infusion process

Foam-filled circular metallic tube has been widely used in safety design of automobile, space craft recovery and so on due to its advantage of high energy absorption. But poor chemical stability and easily oxidized of metal materials seriously threaten the durability and safety of the traditional metallic tube. The application of fiber reinforcement polymer (FRP) can effectively address these issues. In this paper, a simple and innovative foam-filled GFRP tube, fabricated by vacuum assisted resin infusion process, is proposed to enhance the durability and improve the energy absorption capacity. An experimental study was conducted to validate the effectiveness of this kind of absorptor for increasing the energy absorption capacity. Meanwhile, the influences of GFRP skin thickness, diameter of tube, foam density and fiber orientation angle of GFRP mat on failure mode, initial stiffness, stroke efficiency and specific energy absorption were also investigated. An analytical model, considered the confinement effect on foam core and local buckling of GFRP skin, was also developed to predict the ultimate peak strength of foam-filled GFRP tubes. The experimental and analytical results were shown to be well matched.

Effects of Position and Cut-Out Lengths on the Axial Crushing Behavior of Aluminum Tubes: Experimental and Simulation

Effects of Position and Cut-Out Lengths on the Axial Crushing Behavior of Aluminum Tubes: Experimental and Simulation

Modeling of Material Orientation Effects on AHSS Crush and Fracture Behavior in Axial Crush Tests

Objective: Due to the rolling manufacturing process, most advanced high-strength steels (AHSS) demonstrate in-plane anisotropic material behavior. This study investigates the effects of material orientation on the axial crush behavior and fracture of AHSS with axial crush tests and computer simulations. Methods: Crush simulation models considering material anisotropy and damage evolution were developed in LS-DYNA based on the drop-tower crush test results and coupon characterization test data for DP780 steel. The modified Mohr-Coulomb (MMC) isotropic fracture model was employed in the crush simulation models for fracture prediction. Results: The 12-sided components fabricated in the transverse (T) direction of the sheet exhibited slightly higher crush loads and reduced crush distances compared to those in the longitudinal (L) direction. The crush behavior in each direction was generally proportional to ultimate tensile strength. All of the materials investigated in this study showed some cracking in the crush tests for both component orientations, but only DP780 showed significant anisotropy in fracture behavior with more cracking for the T direction compared to the L direction. Overall, the amount of cracking observed in the tests had little or no significant effect on the axial crush performance. The MMC fracture loci in both the L and T directions were determined using a reverse engineering approach, and the stress–strain curves beyond the uniform elongation point were extended using an optimization method. Both material models MAT103 and MAT224 predicted the crush and fracture behavior with reasonably good accuracy. Conclusions: The predicted fracture mode and force–displacement curves agreed well with the test data for both the L and T directions in axial crush tests of the 12-sided components. The simple isotropic material model MAT224 is adequate for crush simulations to predict material orientation effects on AHSS component crush performance and fracture behavior.

On The Axial Crushing Behavior of a Thin-Walled Cylindrical Shell With a Hollow Foam Core

On The Axial Crushing Behavior of a Thin-Walled Cylindrical Shell With a Hollow Foam Core

Analytical and experimental studies on quasi-static axial crush behavior of thin-walled tailor-made aluminum tubes

In this paper, the crush behavior of segmented circular tubes, made of aluminum alloy 6061 and subjected to quasi-static axial loading, has been analytically and experimentally investigated. Crush behavior of these tubes was modeled by integrating available analytical models and superposition principle. In the certain overall length of segmented circular tubes, effects of changing the wall thickness and length of each segment on the energy absorption characteristics have been evaluated. One successful approach toward obtaining lightweight energy absorbers with high energy absorption capacity is the use of thin-walled Tailor-Made Tubes (TMTs). In these tubes, the thickness and mechanical properties of the wall vary along the length of the tube. Applying these tubes; crush force can be controlled by changing the length and thickness of each tube segment, improving the performance of energy absorbing systems. Results of this research showed that Tailor-made tubes have higher energy absorption capacity at identical crush lengths, and they can absorb more energy per unit weight compared to simple tubes with constant wall thickness and mechanical properties. Moreover, for the same specific energy absorption, the TMTs exhibit a considerable reduction in the magnitude of the mean and initial maximum crush forces. With the use of TMTs, the maximum crush force shifts to the end of the crush range, reducing the exerted deceleration on occupants and equipments. Comparing mean crush force and specific energy absorption obtained by analytical and experimental approaches, it was observed that combining current analytical models with superposition principle can prepare a set of analytical formulations to predict TMTs crush characteristics within an acceptable proximity.

Quasi-Static Axial Crushing Behavior of Honeycomb-Filled Thin-Walled Aluminum Tubes

The experimental and numerical quasi-static crushing behaviors of Nomex™ honeycomb-filled thin-walled Al tubes were investigated. The honeycomb filler was modeled using a unit cell model. The numerical model and experimental results have shown that, 6.4 mm and 4.8 mm cell size honeycomb filling had no effect on the deformation mode (diamond); however 3.2 mm cell size honeycomb filling changed the deformation mode to mixed/concertina. Honeycomb filling was also shown to increase the specific energy absorption of filled tubes over that of Al tube. The specific energy absorption of honeycomb filling was further compared with those of tube wall thickening and Al closedcell foam filling.

A Computational Investigation on the Effects of Hull Geometry and Stiffeners on the Axial Crushing Strength and Behavior of Aluminum High Speed Crafts

This work focuses on the crushing behavior of aluminum high speed crafts in the case of axial bow collision to a rigid structure. LS-DYNA code is used in analyses. Some available experimental prototypes tested under axial loading are first successfully simulated in the LS-DYNA environment. Then the effects of hull breadth, hull curvature, and longitudinal stiffeners on the crushing strength and behavior of the aluminum high speed craft are investigated in detail.

Rapid Composite Tube Manufacture Utilizing the QuickstepTM Process

In this study, a novel method for manufacturing composite tubes utilizing the QuickstepTM process has been developed. Tubes manufactured from `quick-cure' Toray G83C prepreg have demonstrated highly repeatable axial crush behavior with an average specific energy absorption (SEA) of 86 kJ/kg. The cure cycle is optimized by comparing the results from compression, dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and porosity testing. The tube lay-up is optimized using compression and porosity test results. The effect of changes in fiber-orientation on SEA is also investigated. Process development has resulted in a robust manufacturing method capable of producing fully cured, high performance composite tubes with a cure cycle of 7 min. This corresponds to a 95% reduction in time compared to an equivalent autoclave cycle.

Axial Crushing Behavior and Energy Absorption Capability of Al/CFRP Square Tubes for Light-Weights

An aluminum or CFRP (Carbon Fiber Reinforced Plastics) tube is representative light-weight materials but its axial collapse mechamism is different from each other. The aluminum tube absorbs energy by stable plastic deformation, while the CFRP tube absorbs energy by unstable brittle failure with higher specific strength and stiffness than those in the aluminum tube. In an attempt to achieve a synergy effect by combining the two members, aluminum/CFRP square tubes were manufactured, which are composed of aluminum tubes wrapped with CFRP outside aluminum square tubes with different fiber orientation angle and thickness of CFRP, and axial collapse tests were performed for the tubes. The crushing behavior and energy absorption capability of the tubes were analyzed and compared with those of the respective aluminum square tubes and CFRP square tubes. Test results showed that the collapse of the aluminum/CFRP square tube complemented unstable brittle failure of the CFRP square tube due to ductile characteristics of the inner aluminum square tube. The collapse modes were categorized into four modes under the influence of the fiber orientation angle and thickness of CFRP. The absorbed energy per unit mass, which is in the light-weight aspect, was higher in the aluminum/CFRP square tube than that in the aluminum square tube or the CFRP square tube alone.

Axial Crush of Strengthening Structural Members with Various Hat-Shaped Cross-Sections. 2nd Report, FEM Simulation of Collapse Process.

Axial crush behavior of strengthening structural members is numerically simulated by the use of the dynamic explicit FEM code DYNA3D. The numerical model of the structure is composed of the shell elements and the material is assumed as a mild steel or a high tensile strength steel corresponding to the performed experiment. A drop hammer composed of solid finite-elements hits the top edge of the structure at 10 m/s, keeping its lower edge embedded into the rigid base. The calculated hat-shaped cross-sections are three types of rectangles and a more complex shape with a rectangular concave portion on the hat top. The axial length of the strticture is 120∼200 mm. When the accordion type cyclic buckling mode takes place, the crush strength is high and thus the structure attains a high capacity of the energy absorption. Another mode of bending collapse around a single plastic hinge also occurs under some conditions. In this case, the structure has a low capacity of energy absorption and thus is not preferable. The calculated crush strength agrees well with the corresponding experimental result, especially for the high strength material. The crush strength is larger for the shorter hat-height, which is coincident with the experimental result. It is also well simulated numerically that a more complex shape of the cross-section leads a higher crush strength.