Thin-walled Square Research Articles

Matching effect of honeycomb-filled thin-walled square tube—Experiment and simulation

Honeycomb-filled thin-walled square tube (HFST) structure is a new outstanding energy absorption component, which has attracted great attention in recent years. This paper aims to present a comprehensive investigation by means of both experiments and numerical simulations. Detailed mechanical and energy absorption properties have been determined for kinds of HFST structures with different geometric configurations. Matching relationships between inside honeycomb core and outside metallic thin-walled structures have been observed. Parametric simulations by means of cell expansion numerical simulation methodology have been carried out to further understand the matching effect. The deformation mode evolution of filling has been determined, together with key influence factors on such a matching effect. Results show that the geometric configuration, the matrix material properties as well as the impact velocity have significant influence on the matching relationships.

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>

Effect of the Installation of Partition Wall in High Strength Thin-Walled Square Tube on Axial Collapsing Behavior

Effect of the Installation of Partition Wall in High Strength Thin-Walled Square Tube on Axial Collapsing Behavior

Bending collapse of square tubes with variable thickness

This paper aims to study the bending collapse behavior of thin-walled square tubes with variable thickness in the cross-section. Three-point bending test is carried out for thin-walled square beams with different thickness for flanges and webs. The relative strength of the flanges versus the web plates is found to have significant influence on the force response and deformation pattern. Numerical simulation of the experimental test is also performed and the numerical results compared very well with the experimental results. Moreover, the difference between the quasi-static and dynamic responses of the square tubes under transverse loading is analyzed. A response surface method is finally employed to optimize two thin-walled beams under impact loading. The optimization results show that putting less material in flanges and more in the web plates is an efficient way to improve the bending resistance of the beams under transverse loading. Adopting graded thickness in the web plates is an effective and promising approach to further increase the energy absorption efficiency of the beams.

Numerical and experimental investigations of the post-buckling behaviour of square cross-section composite tubes

The buckling and post-buckling behaviour of thin-walled square cross-section tubes subjected to static compression is presented. The columns under consideration were made with the autoclaving technique of eight layers of a glass fibre reinforced polymer unidirectional prepreg tape. Six different arrangements of layers were taken into account. The following experimental data were collected: force–displacement relations obtained from a Zwick/Roel universal testing machine, strains at chosen points of the tube measured with a strain gauge technique, a map of deflections obtained with a non-contact 3D optical method (Aramis System, made by GOM company). All those results were used to determine buckling load and equilibrium paths in the pre- and post-buckling range. A numerical model of the analysed tube was prepared with the ANSYS software. A linear and nonlinear buckling analysis was performed. The experimental results were used to validate the proposed FEM model. An influence of the layer arrangement on the buckling and post-buckling behaviour, differences between the numerical and experimental results and the methods employed for buckling load determination are discussed.

Numerical simulation on seismic collapse of thin-walled steel moment frames considering post local buckling behavior

Steel moment frame buildings face severe collapse potentials when subjected to earthquakes beyond the design level. Reliable numerical modeling of steel moment frames is significant to assess the critical parameters affecting collapse behavior. A fiber-element model is presented to evaluate post-local buckling behavior for steel structures. A constitutive relationship was defined for material properties taking into account of post-local buckling degradation in strength and stiffness. The model is compared with quasi-static test databases related to H-shaped steel, circular and rectangular hollow steel section (HSS) members. Three parameters, including strength, associated deflection and post-peak degradation were reasonably simulated. Significant strength degradation was triggered by the local buckling in the thin-walled HSS beam–columns. The numerical model well presented the collapse of a steel moment frame tested by E-Defense shaking table. The results show that the thin-walled square HSS column components induced low-ductile collapse behavior due to the prior local buckling at the bottom storey. The proposed fiber-element model provides a simple alternative method for predicting deterioration and collapse of steel frames under extreme earthquakes.

Mechanics of Energy Absorption by Progressive Plastic Deformation of a Square Column with an Ellipsoidal Bulge Base

Thin-walled square columns are generally used as energy absorber in various applications due to their ease of fabrication and installation, high energy absorption capacity in terms of progressive plastic deformation and long stroke. However, the main drawback of a standard square column is the high initial peak force. An ellipsoidal bulge base is proposed to overcome this shortcoming and at the same time to improve the crush performance. Static axial crushing were performed by finite element analysis to determine the initial peak force (IPF), crush force efficiency (CFE) and plastic specific energy absorption (SEA) of columns having ellipsoidal bulge bases with various thicknesses. It was found that the bulge base significantly enhanced the column crush performance as well as the deformation characteristics. A comparison with the plain square column was carried out and it was found that the bulge base reduced the initial peak force and increased the crush force efficiency. A simple analytical approach is proposed to predict the reduction of initial peak force with the use of this trigger mechanism

Deformation, energy absorption and crushing behavior of single-, double- and multi-wall foam filled square and circular tubes

Deformation and energy absorption studies with single, double and multi-wall square and circular tube structure with and without aluminum foam core are carried out for assessing its effectiveness in crashworthiness under the identical test conditions. Modeling and numerical simulation of aluminum foam filled square tubes under axial impact loading is presented. The foam-filled thin-walled square tubes are modeled as shell wherein, foam core is modeled by incorporating visco-elastic plastic foam model in Altair® RADIOSSTM. It is observed that the multi-wall tube structure with foam core alters the deformation modes considerably and results in substantial increase in energy absorption capacity in comparison with the single and multi-wall tube without foam core. Moreover, the multi-wall tube foam filled structure shows mixed deformation modes due to the significant effect of stress wave propagation. This study will help automotive industry to design superior crashworthy components with multi-tube foam filled structures and will reduce the experimental trials by conducting the numerical simulations.

Mechanical properties and energy absorption capability of thin-walled square columns of silica/epoxy nanocomposite

In this paper, the effect of adding silica nanoparticle to epoxy, silica weight percent, particle size and various combinations of epoxy/silica on Young’s modulus, yield strength and energy absorption capability of thin-walled square columns was investigated. Two different sizes of silica nanoparticles, nominally 17nm and 65nm in diameter, were used. Nanosilica particles were dispersed almost homogeneously in the epoxy resin from 1.5wt.% to 6wt.% in three series of composites. First and second series were composites reinforced with 17nm and 65nm particle size, respectively and third series were composites reinforced with combination of both particle sizes. All specimens were tested under quasi-static loading using a servohydraulic Instron machine. A scanning electron microscopy (SEM) was used for fracture surface studies. The results showed that when silica weight percent was increased, the Young’s modulus increased, yield strength remained constant and energy absorption capability of columns decreased, and specimens collapsed under unstable and dangerous mode. It was observed that the reason for this type of collapse was initiation of axial cracks at an early stage of the loading and propagation along the specimen height. Energy absorption capability for columns with height of 60mm and 90mm was also investigated and results showed that this parameter for shorter specimens was higher in the same combination of a nanocomposite. Moreover, the effect of particle size on Young’s modulus, yield strength and energy absorption capability was not considerable. Using both particles in a combination did not show any important synergy effect. And finally, fracture surfaces of the specimens showed that surface roughness was increased by increasing the silica nanoparticles.

Energy Absorption Capabilities Of Aluminium Foam-filled Square

In this study compression behavior and energy absorption capacity of aluminium foam-filled square tubes under the divers strain rate in between 0.01 to 1/s at room temperature were studied. The foam-filled thin-wall square tube were made up of aluminium tube, aluminium tube as its shell and closed-cell LM 30 + 15% SiCp Al-alloy foam as its core. The result shows that the plateau region of the stress-strain graph exhibited marked fluctuant serration which is clearly related formation of the folds. The axial deformation mode of foam-filled square tube were the same as the empty sample tube, but the fold number of foam-filled sample tube were more than that of empty sample tubes. The axial compression load and specific energy absorption rate of foam-filled sample tubes were higher compared to the sum of the empty sample tubes and aluminium foam due to the contact between tube & foam-filled. When compare with empty aluminium tube samples to foam filled samples, energy absorption increases considerably. This work indicates the excellent ability of Al-alloy foam in application in which it is necessary to absorb compressed energy. Copyright © 2015 VBRI Press.

Experimental Investigation on Energy Absorption of Auxetic Foam-filled Thin-walled Square Tubes under Quasi-static Loading

Auxetic materials are modern class of materials that have recently been gaining popularity within the research community due to their enhanced mechanical properties. Unlike conventional materials, they exhibit a negative Poisson's ratio when subjected to a uniaxial loading. This present research experimentally investigates the crush response and energy absorption performances of auxetic foam-filled square tubes under axial loading. For comparison, the crush response and energy absorption of empty and conventional foam-filled squares tubes have also been examined with respect to deformation modes and force displacement curve. Standard compression tests were conducted on a series number of thin-walled tube samples. An additional compression test on conventional and auxetic foam has also been conducted to observe the behavior of foam itself. It is evident that the auxetic foam-filled square tubes are superior to empty and conventional foam-filled square tubes in terms of energy absorption capacity. It shows that such tube is preferable as an impact energy absorber due to their ability to withstand axial loads effectively. Furthermore, it is found that the load capacity increases as the crush length increases. The primary outcome of this study is design information for the use of auxetic foam-filled square tubes as energy absorbers where impact loading is expected particularly in crashworthiness applications.

Experimental and Numerical Study - Effects of Crush Initiators under Quasi-Static Axial Load of Thin Wall Square Tube

Crush initiators are used to improve the energy absorption and reduce the peak crush load at the time of the initial accident. This study aims to determine the effect of crush initiators on thin-walled square tube of local product which is applied on the front rail Electric Cars University of Indonesia under the quasi static axial loads. Crush initiator was designed in the form of two parallel holes with a diameter of 6.5 mm at a distance of 20 mm from the surface of the tube on each side. Analysis was done by comparing the experimental result with the result of numerical analysis by using finite element method of ANSYS. The result showed the significant effect from the crush initiators on decreasing the peak crush load and increasing the energy absorption and showed a similar pattern between the experimental and numerical computation result.

Response of Filled Thin-Walled Square Tubes to Axial Impact Load

This paper presents the results of an investigation into the response of thin-walled square (60x60 mm and 76x76 mm) tubes made from mild steel filled with four different fillers; aluminium foam (Cymat 7%), two types of aluminium honeycomb and polyurethane foam to quasi-static and dynamic axial impact load. The energy absorption characteristics of the foam-filled tubes are compared to that of a hollow tube, through efficiency calculations. The tubular structures are subjected to axial impact load generated by drop masses of 320 kg and 390 kg released from a height ranging between 2.1 m to 4.1 m. Footage from a high speed camera is used to determine the average crush forces exerted by each specimen. The results show that the fillers have insignificant effects on the initial peak forces based on the quasi-static results but increase the overall mean crushed force. The findings also indicate that the fillers affect at times the size of the lobe formed thus compromising the energy absorption capacity of the tube.

Numerical Simulation Study on the Thickness of Cylinder Influencing on Energy-Absorbing Characteristics

According to the problem that the thickness change of the square cylinder as energy-absorption component affect energy-absorption characteristics of the square cylinder, this paper researches that the thickness of the square cylinder for energy-absorption component of the square cylinders influence through theoretical analysis and using numerical calculation method. The theoretical part in this paper analyze local deformation of the square cylinder theoretical model as a result of axial compression ,and in the numerical simulation part this paper simulate the dynamic response of the thin wall square cylinder model structure , thereby research the thickness change of the square cylinder influence on energy-absorption characteristics of the square cylinder. At last, the change curve of the force-deformation is drawn with the change curve of force-peak load, and it is obtained law that the thickness of the square cylinder influence on energy-absorption characteristics the square cylinder and optimum thickness.

1402 機械構造物を対象とした構想設計支援法の構築(OS16 モデルベースデザイン,ファーストオーダーアナリシス)

Computer Aided Engineering (CAE) has been successfully used in many mechanical industries such as automotive industries. However, most mechanical designers, in fact, cannot utilize CAE applications by themselves because of the sophisticated operations and a huge amount of time for the analysis. Recently, the concept of a new CAE, First Order Analysis (FOA), has been proposed in order to overcome these problems. This paper presents the method to support the conceptual designs using simplified model corresponding to the concept of FOA. First, thin-walled square hallow section T-joint model consideration of corner R on joint-section is introduced. Next, a procedure for determining the stiffness of joint-section is proposed, and the derived expression is presented. Finally, some examples are provided to confirm the method proposed here.

Axial Crushes Simulation of Thin-walled Square Aluminum Alloy 6061-T5 Foam-filled Section

This paper deal with numerical study of the dynamic impact of axial crushing on thin-walled extrusion aluminum alloy 6061 and polystyrene foam-filled tubes square cross-section. Non-linear dynamic-impact simulation was done using finite element software's package as well on foam-filled model. Non-linear dynamic finite elements were carried out to simulate buckling and crushing phenomenon in the crushed event. Influence of fillers on the energy absorption behavior of square and thin-walled metal tube extrusion aluminum alloy 6061 estimates empty and foam-filled examined. Three main decay modes have been identified for the model is crushes, for example, diamond compound symmetry, axisymmetric concertina mode of formation and mixing times. Three different arrangement foam-filled inner tube columns has been examined and investigated.

Axial Crushes on Composite Laminated Square Tubes under Compressive Loading

In this paper presents the effect of energy absorption on thin-walled aluminum cross-section square tubes wrapped with woven E-glass fiber laminated composite subjected to quasi-static axial compression. The compression test was carried out experimentally to examine the amount of energy can be absorbed as well as to observe for failure behavior for each specimens. The wall-thicknesses aluminum square of 1.9 mm was investigated and woven E-glass fiber laminate reinforced polyester resin was examined. Two different numbers of layers woven E-glass were investigated and examined. Result obtained from experimental analysis such that initial peak load, mean load, quasi-static absorbed energy against displacement curves were recoded and plotted then compared for each specimen profile. Results indicated that the tubes crashworthy structure was affected significantly by different number of layers wrapped on wall aluminum square profile and also that the effect of crushing behaviors and failure modes was discussed.

Energy Absorption of Hybrid Composite Tubes under Axial Compression

The effect of specific absorbed energy on pultruded profile and thin-walled aluminum composite square cross-section tubes were studied via experimentally. The type of strand mat E-glass reinforced polyester resin was conducted in this study. The specimens of square pultruded and thin-walled wrapped strand mat E-glass composite were compressed under quasi-static of obliquely loadings from the top moving plat platen. For each specimen of composite tubes, triggering mechanism was applied on frontal end top of the tube to obtain the progressive failure throughout the crash event. The pultruded profile tube wall-thicknesses of 2.1 mm and thin-walled aluminum 1.9 mm thickness wrapped 3 layer woven fabric were examined, and the effects of crushing behaviors and failure modes were discussed. Results showed that the tubes energy absorption capability was affected significantly by different type of composite made in term of internal energy.

Effect of Rolling Direction to the Strength of a Thin-Walled Steel SHS Beam under Concentrated-Compressive Load and Bending Moment

In this research, it has been carried out the development of a strength analytical method of a thin-walled steel square pipe (Square Hollow Section/SHS) affected by the interaction of concentrated-compressive load and bending moment then it verified by experimental approach. The experimental approach was consisted of measuring a basic material property and the strength of the investigated SHS pipe. The basic material property identified parallel to rolling direction (0o) and perpendicular to rolling direction (90o). The analytical data obtained from cut-off strength method is generally scattered within the acceptable limits of ± 20 % and tends to be in unconservative region. The actual data measured from experiments shows that SHS beam with t = 0.6 mm and longitudinal axis parallel to the rolling direction of base material has higher strength compared to the one of the SHS beam with t= 0.6 mm and longitudinal axis perpendicular to the rolling direction, meanwhile the SHS beam with t= 1.2 mm is tends to be equal. This means that the rolling direction of base material can be considered to be a parameter in the strength design of a thin-walled SHS beam

Numerical and Experimental Impact Analysis of Square Crash Box Structure with Holes

Numerical and experimental study of the effects of center holes located at opposite sides on dynamic axial crushing of thin-walled square aluminum extrusions column are presented in this paper. The results showed that, by inserting the holes, the impact energy absorption characteristic in a progressive buckling can be improved as the starting location of the plastic deformation is always from holes and peak crush force can be decrease, so that the deceleration does not exceed the limit that can injure the passenger when frontal impact occurs. Here, the results of numerical simulations, conducted using an explicit finite element code, are compared with experimental results for various hole diameter. The results shows that the peak crushing force is decrease, while the mean crushing force is relatively constant.