Crushing of circular steel tubes filled with nanoporous-materials-functionalized liquid

2016 ◽  
Vol 27 (3) ◽  
pp. 439-450 ◽  
Author(s):  
Yueting Sun ◽  
Yibing Li ◽  
Cang Zhao ◽  
Meng Wang ◽  
Weiyi Lu ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Tube Wall ◽  
General Rule ◽  
Nanoporous Materials ◽  
Steel Tubes ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Infiltration Pressure ◽  
Load Carrying ◽  
Thin Walled

The crush behaviors of steel tubes filled with nanoporous-materials-functionalized liquids are experimentally investigated under quasi-static and dynamic conditions. Results show that the nanoporous-materials-functionalized liquid can enhance the load-carrying and the energy absorption capacities of thin-walled tubes, as the buckling mode is affected. The effective buckling stress increases with the infiltration pressure, and the overall compressibility is highly dependent on the nanopore volume. A general rule of designing nanoporous-materials-functionalized liquid-filled tubes is proposed. The interaction between the tube wall and the nanoporous-materials-functionalized liquid is analyzed.

ELASTIC BUCKLING OF THIN-WALLED CIRCULAR TUBES CONTAINING AN ELASTIC INFILL

2006 ◽  
Vol 06 (04) ◽  
pp. 457-474 ◽  
Author(s):  
M. A. BRADFORD ◽  
A. ROUFEGARINEJAD ◽  
Z. VRCELJ
Keyword(s):  
Axial Compression ◽  
A Priori ◽  
Local Buckling ◽  
Steel Tube ◽  
Transcendental Equation ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Elastic Tubes ◽  
Thin Walled ◽  
Energy Formulation

Circular thin-walled elastic tubes under concentric axial loading usually fail by shell buckling, and in practical design procedures the buckling load can be determined by modifying the local buckling stress to account empirically for the imperfection sensitive response that is typical in Donnell shell theory. While the local buckling stress of a hollow thin-walled tube under concentric axial compression has a solution in closed form, that of a thin-walled circular tube with an elastic infill, which restrains the local buckling mode, has received far less attention. This paper addresses the local buckling of a tubular member subjected to axial compression, and formulates an energy-based technique for determining the local buckling stress as a function of the stiffness of the elastic infill by recourse to a transcendental equation. This simple energy formulation, with one degree of buckling freedom, shows that the elastic local buckling stress increases from 1 to [Formula: see text] times that of a hollow tube as the stiffness of the elastic infill increases from zero to infinity; the latter case being typical of that of a concrete-filled steel tube. The energy formulation is then recast into a multi-degree of freedom matrix stiffness format, in which the function for the buckling mode is a Fourier representation satisfying, a priori, the necessary kinematic condition that the buckling deformation vanishes at the point where it enters the elastic medium. The solution is shown to converge rapidly, and demonstrates that the simple transcendental formulation provides a sufficiently accurate representation of the buckling problem.

Effects of Wall Thickness and Crush Initiators Position under Experimental Drop Test on Square Tubes

2017 ◽  
Vol 865 ◽  
pp. 612-618 ◽  
Author(s):  
M. Malawat ◽  
Jos Istiyanto ◽  
D.A. Sumarsono
Keyword(s):  
Energy Absorption ◽  
Tube Wall ◽  
Impact Load ◽  
Peak Load ◽  
Load Force ◽  
Drop Height ◽  
Thin Walled ◽  
The Impact ◽  
Initial Peak ◽  
Load Mass

Crush initiators are the weakest points to reduce initial peak load force with significant energy absorption ability. The objective of this paper is to study the effects of square tube thickness and crush initiators position for impact energy absorber (IEA) performance on thin-walled square tubes. Two square tubes having thickness about 0.6 mm (specimen code A) and 1 mm (specimen Code C) were tested under dynamic load. The crushing initiator is designed around the shape of the tube wall and has eight holes with a fixed diameter of 6.5 mm. In the experiment, the crushing initiator was determined at 5 different locations on the specimen wall. These locations are 10 mm, 20 mm. 30 mm, 40 mm, and 50 mm measured from the initial collision position of the specimen tested. The impact load mass was about 80 kg and had a drop height of about 1.5 m. Using the simulation program of the LabVIEW Professional Development System 2011 and National Instrument (NI) 9234 software equipped with data acquisition hardware NI cDAQ-9174 the signal from the load cell was sent to a computer. By controlling the thickness of the thin-walled square tube, the peak loading force can be decreased by approximately 56.75% and energy absorption ability of IEA can be increased approximately to 11.83%. By using different thin-walled square tube can produce different best crush initiators position with the lowest peak load force.

Energy Absorption of Axial Members With the Inclusion of Functionally Graded Cellular Structure

2015 ◽  
Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma
Keyword(s):  
Energy Absorption ◽  
Cellular Structure ◽  
Tube Wall ◽  
Axial Loading ◽  
Hybrid Structure ◽  
Functionally Graded ◽  
Shell Elements ◽  
Thin Walled ◽  
Energy Absorbing ◽  
Deformation Modes

Axial members are commonly used in automotive structures and are responsible for absorbing significant portion of impact energy in the event of an accident. This study was conducted to investigate the effects of inclusion of functionally graded cellular structures in thin walled members under compressive axial loading. A compact functionally graded cellular structure was introduced inside a 352 mm long square tube with side length and wall thickness of 74 mm and 3.048 mm, respectively. The tube wall material was aluminum. The cellular structure’s geometry was observed in the cross-section of a banana peel that has a specific graded cellular packing in a confined space. This packing enables the peel to protect the internal soft core from external impacts. The same cellular pattern was used to construct the structure in present study. The study was conducted using non-linear finite element analysis in ABAQUS. The hybrid structure (tube and graded cellular structure) was fixed on one side and on the other (free end) side, was struck by a rigid mass of 300 Kg travelling at a velocity of 35 mph (15.64 m/s) along the axis of the square tube and perpendicular to the in-plane direction of the graded cellular structure. The tube and cell walls were discretized using reduced integration, hourglass control, 4 nodes, and hexahedral shell elements. The impact plate was modeled with 4 node rigid shell elements. General contact conditions were applied to define surface interaction among graded structure, square tube, and rigid plate. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, and energy curves, were evaluated. The results showed that the inclusion of graded cellular structure increased the energy absorption capacity of the square tube by 41.06%. The graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the square tube thus delaying local tube wall collapse and promoting outward convex localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that are typically observed in an empty square tube under axial compressive loading. The variation in deformation mode, large contact areas, presence of graded cellular structure resulted in enhanced stiffness of the hybrid structure, and therefore, high energy absorption by the structure. The results of this preliminary study show a potential of functionally graded cellular materials to significantly improve the energy absorbing capacities of thin walled members under axial loading by altering member’s crushing deformation modes.

Improving the Energy Absorption of Cruciform With Large Global Slenderness Ratio by Kirigami Approach and Welding Technology

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Caihua Zhou ◽  
Tong Li ◽  
Shizhao Ming ◽  
Zhibo Song ◽  
Bo Wang
Keyword(s):  
Energy Absorption ◽  
Progressive Collapse ◽  
Slenderness Ratio ◽  
Absorption Capacity ◽  
Buckling Mode ◽  
Euler Buckling ◽  
Thin Walled Structures ◽  
Welding Technology ◽  
Parametric Studies ◽  
Thin Walled

Conventional energy absorber usually employs stubby thin-walled structures. Compared with the limited number of stubby thin-walled structures, an equipment has a large number of slender thin-walled structures that has the potential to be used for energy absorption purpose as well. Therefore, improving the energy absorption capacity of these slender thin-walled structures can significantly benefit the crashworthiness of the equipment. However, these slender structures are inclined to deform in Euler buckling mode, which greatly limits their application for energy absorption. In this paper, kirigami approach combined with welding technology is adopted to avoid the Euler buckling mode of a slender cruciform. Both finite element simulations and experiments demonstrated that the proposed approach can trigger a desirable progressive collapse mode and thus improve the energy absorption by around 155.22%, compared with the conventional cruciform. Furthermore, parametric studies related to the kirigami pattern and global slenderness ratio (GSR) are conducted to investigate the improvement of this proposed approach on the energy absorption and the maximum critical value of GSR.

Crush Characteristics and Energy Absorption of Thin-Walled Tubes with Through-Hole Crush Initiators

2014 ◽  
Vol 606 ◽  
pp. 181-185 ◽  
Author(s):  
S. Kanna Subramaniyan ◽  
Arun Kumar Kananasan ◽  
Mohd Radzi Mohamed Yunus ◽  
Shahruddin Mahzan ◽  
Mohd Imran Ghazali
Keyword(s):  
Experimental Investigation ◽  
Energy Absorption ◽  
Static Loading ◽  
Absorption Capacity ◽  
Peak Force ◽  
Energy Absorption Capacity ◽  
Steel Tubes ◽  
Thin Walled ◽  
Through Hole ◽  
Initial Peak

An experimental investigation was conducted to compare the crush characteristics and energy absorption capacity of circular and square tubes with located through-hole crush initiator. Circular through-holes were fabricated at three different configurations based on location into steel tubes which had a length of 200 mm. Furthermore, two different side configurations along the tube were considered for introducing the crush initiators. The results found that adding crush initiator onto the tubes were effectively reduced the initial peak force of a thin-walled circular and square tubes under axial quasi-static loading. The peak crush force was reduced within a range 3-10% and 5-16% for circular and square tubes respectively when compared with corresponding tubes without crush initiator. Moreover, the energy absorption capacity of the tubes was independent with the incorporation of through-hole crush initiators. However, the energy absorption of circular and square tubes were slightly decreases when compared with the tubes fabricated four sided crush initiation and tubes without crush initiator. Overall, the effect of location and number of crush initiation proved significantly influences the initial peak forces while maintain the energy absorbed.

Rate Dependent Reinforcement of Liquid Nanofoam on Thin-Walled Tubes

2017 ◽  
Author(s):  
Mingzhe Li ◽  
Bang He ◽  
Saeed Barbat ◽  
Sihao Gu ◽  
Weiyi Lu
Keyword(s):  
Energy Absorption ◽  
Hybrid Structure ◽  
Absorption Efficiency ◽  
Theoretical Limit ◽  
Rate Dependent ◽  
Buckling Stress ◽  
Energy Absorption Efficiency ◽  
Post Buckling ◽  
Thin Walled ◽  
Solid Liquid

Thin-walled metal tubes have been widely used as energy absorbers to mitigate adverse effects of impact and protect structures and facilities. However, once the initial buckling stress of the tube is reached, the post-buckling plateau of the tube has a much reduced average stress which determines the energy absorption efficiency of the empty tube. As a result, the real energy absorption efficiency of the thin-walled tube is much lower than the theoretical limit which is proportional to the value of initial buckling stress. We hypothesize that by filling thin-walled tubes with the novel liquid nanofoam (LN), (i) the energy absorption efficiency of the hybrid structure can reach the theoretical limit, and (ii) the main working mechanism is the effect of solid-liquid interaction on tube buckling. To test these hypotheses, we have characterized the energy absorption efficiency of LN filled steel tubes by using quasi-static compression tests and dynamic impacts. The quasi-static behavior of LN filled tubes is characterized by an Instron 5982 universal tester. Results show that the gravimetric and volumetric energy absorption efficiencies of LN filled steel tubes are 20% and 220% higher than the values of empty tubes, respectively. This is due to the changed buckling mode and the promoted post-buckling stress of the hybrid structure by the highly compressible LN. The dynamic behavior of LN filled tubes is characterized by a dynamic impact test (∼3 m/s) with a lab-customized drop tower apparatus. It is found that both the gravimetric and volumetric energy absorption efficiencies of LN filled tubes are further increased by 16%. The strain rate dependent behavior of LN filled tubes must be attributed to the solid-liquid interaction between the LN and the steel tube wall, which is further verified by comparing the mechanical behaviors of LN filled tubes with solid foams filled tubes. Our experimental results have demonstrated that the energy absorption efficiency of thin-walled tubes are significantly improved by the LN filler especially at higher strain rates. This hybrid structure may have a potential for future use in the design of light-weight and small scale cellular structures for vehicle safety and crashworthiness.

Flexural-torsional buckling of FRP thin-walled composite with various sections

2014 ◽  
Vol 21 (4) ◽  
pp. 537-549 ◽  
Author(s):  
Yeliz Pekbey ◽  
Esmaeil Ghanbari
Keyword(s):  
Mode Shapes ◽  
Torsional Buckling ◽  
Buckling Mode ◽  
Closed Form Solutions ◽  
Buckling Stress ◽  
Reinforced Plastic ◽  
Compressive Loads ◽  
Thin Walled ◽  
Flexural Torsional Buckling ◽  
Potential Energy Method

AbstractThe flexural-torsional buckling of thin-walled pultruded fiber-reinforced plastic (FRP) members composed of unstiffened, stiffened cruciform- and I-shaped sections under uniform compressive loads was investigated using finite element methods (FEM). As the basic method, an eigenvalue solution using the minimum potential energy method was utilized to obtain the critical buckling stress and buckling mode shapes. FEM results were compared with the closed-form solutions and literature results. Furthermore, a parametric study was carried out to investigate the different cross-section geometries and span lengths on the critical buckling stresses and buckling mode shapes, that is, flexural, torsional, or mixed buckling.

Experimental and numerical studies on failure and energy absorption of composite thin-walled square tubes under quasi-static compression loading

2020 ◽  
Vol 21 (6) ◽  
pp. 623-634
Author(s):  
Haolei Mou ◽  
Zhenyu Feng ◽  
Jiang Xie ◽  
Jun Zou ◽  
Kun Zhou
Keyword(s):  
Finite Element ◽  
Shell Model ◽  
Energy Absorption ◽  
Failure Mode ◽  
Failure Criterion ◽  
Finite Element Models ◽  
Static Compression ◽  
Compression Loading ◽  
Thin Walled ◽  
Simulation Results

AbstractTo analysis the failure and energy absorption of carbon fiber reinforced polymer (CFRP) thin-walled square tube, the quasi-static axial compression loading tests are conducted for [±45]3s square tube, and the square tube after test is scanned to further investigate the failure mechanism. Three different finite element models, i.e. single-layer shell model, multi-layer shell model and stacked shell mode, are developed by using the Puck 2000 matrix failure criterion and Yamada Sun fiber failure criterion, and three models are verified and compared according to the experimental energy absorption metrics. The experimental and simulation results show that the failure mode of [±45]3s square tube is the local buckling failure mode, and the energy are absorbed mainly by intralaminar and interlaminar delamination, fiber elastic deformation, fiber debonding and fracture, matrix deformation cracking and longitudinal crack propagation. Three different finite element models can reproduce the collapse behaviours of [±45]3s square tube to some extent, but the stacked shell model can better reproduce the failure mode, and the difference of specific energy absorption (SEA) is minimum, which shows the numerical simulation results are in better agreement with the test results.

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