Numerical simulation of hybrid composite tubes under oblique compression

2017 ◽  
Vol 14 (2) ◽  
pp. 173-177 ◽  
Author(s):  
Al Emran Ismail ◽  
N. Nezere

Purpose An energy-absorbing device is an important tool that is capable of increasing the survivability of passengers in vehicles. Generally, empty metallic tubes are used, and it is found that the energy absorption capability is lower than the energy obtained using composite materials. Therefore, this paper numerically presents the crushing performances of hybrid tubes under axial and oblique compressions. Design/methodology/approach Three important parameters are used such as fiber thicknesses, fiber orientations and oblique compression angles. Epoxy-reinforced fibers are wrapped around the steel tubes and it is then modeled numerically using the ANSYS finite element program. Belytscho – Tsay shell element is used to model the composites, while a bilinear kinematic hardening model is used to model the steel tube. A proper contact algorithm is implemented to prevent interpenetration among elements and surfaces. Findings A proper contact algorithm is implemented to prevent interpenetration among elements and surfaces. Hybrid tubes are quasi-statically crushed and force–displacement curves are extracted and analyzed. Originality/value It is found that the introduction of oblique compressions has induced bending moments and therefore decreases the energy absorption capability. Varying fiber orientations also insignificantly changed the crushing performances. However, wrapping carbon/epoxy composite that is capable of strengthening the tubes, is also subjected to oblique compression compared with the glass/epoxy composites.

2011 ◽  
Vol 291-294 ◽  
pp. 396-400 ◽  
Author(s):  
Yan Wang ◽  
Guan Yuan Zhao

Reactive Powder Concrete(RPC) is a cementitious material that exhibits high performance properties. Brittle failure mode usually appears when it is subjected to high or complicated stress. The fragility performance of RPC can be great improved if efficient confinement is provided. In this paper, four RPC-filled steel tube stub columns under axial loads were analyzed using the finite element program ABAQUS. Two different axially loading modes were considered. The analysis results were compared with the results of the tests. It was found that the FEM models can predict the force-displacement relationship of such columns with acceptable accuracy.


2015 ◽  
Vol 21 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Dixon M Correa ◽  
Timothy Klatt ◽  
Sergio Cortes ◽  
Michael Haberman ◽  
Desiderio Kovar ◽  
...  

Purpose – The purpose of this paper is to study the behavior of negative stiffness beams when arranged in a honeycomb configuration and to compare the energy absorption capacity of these negative stiffness honeycombs with regular honeycombs of equivalent relative densities. Design/methodology/approach – A negative stiffness honeycomb is fabricated in nylon 11 using selective laser sintering. Its force-displacement behavior is simulated with finite element analysis and experimentally evaluated under quasi-static displacement loading. Similarly, a hexagonal honeycomb of equivalent relative density is also fabricated and tested. The energy absorbed for both specimens is computed from the resulting force-displacement curves. The beam geometry of the negative stiffness honeycomb is optimized for maximum energy absorption per unit mass of material. Findings – Negative stiffness honeycombs exhibit relatively large positive stiffness, followed by a region of plateau stress as the cell walls buckle, similar to regular hexagonal honeycombs, but unlike regular honeycombs, they demonstrate full recovery after compression. Representative specimens are found to absorb about 65 per cent of the energy incident on them. Optimizing the negative stiffness beam geometry can result in energy-absorbing capacities comparable to regular honeycombs of similar relative densities. Research limitations/implications – The honeycombs were subject to quasi-static displacement loading. To study shock isolation under impact loads, force-controlled loading is desirable. However, the energy absorption performance of the negative stiffness honeycombs is expected to improve under force-controlled conditions. Additional experimentation is needed to investigate the rate sensitivity of the force-displacement behavior of the negative stiffness honeycombs, and specimens with various geometries should be investigated. Originality/value – The findings of this study indicate that recoverable energy absorption is possible using negative stiffness honeycombs without sacrificing the high energy-absorbing capacity of regular honeycombs. The honeycombs can find usefulness in a number of unique applications requiring recoverable shock isolation, such as bumpers, helmets and other personal protection devices. A patent application has been filed for the negative stiffness honeycomb design.


2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Junxian Zhou ◽  
Ruixian Qin ◽  
Bingzhi Chen

The implementation of graded thicknesses in structural designs is an efficient strategy for improving the energy absorption performance of thin-walled columns. In this study, the mechanical responses of square columns with double-surfaced gradients under axial crushing forces were analytically and numerically investigated. A mathematical expression for the mean crushing force on a novel tube design is derived according to the super folding element method by introducing two novel parameters: the average thickness of the efficient energy absorbing region (EEAR) and global average thickness. The analytical predictions show good agreement with the simulation results that were obtained using the nonlinear finite element program ANSYS/LS-DYNA. The results demonstrate that a greater coefficient of average thickness of the EEAR versus global average thickness improves the energy absorption efficiency. However, increasing this coefficient largely depends on the sectional material distribution law. To explore the effects of this law on crushing responses, three different material distribution types were investigated. A significant improvement in specific energy absorption (approximately 30%) was obtained for a double-surfaced column with an optimized material distribution type compared to that of a square column with a uniform thickness.


2011 ◽  
Vol 71-78 ◽  
pp. 3662-3665
Author(s):  
Bao Cheng Zhao ◽  
Qiang Gu

Eccentrically braced steel frames are a lateral load-resisting system which apply high intensity area and it can provide the high elastic stiffness that met higher steel building drift requirement. This paper first provides an introduction of Forces in links and Energy dissipation mechanisms of eccentrically braced steel frames. In that Eccentrically braced steel frames will collapse after the link beams go into plastic deformation under earthquake load, A new analytical model which include shell element apply to link beams with large deformation and plastic deformation and beams element apply to other parts of structure is presented in this paper for analyzing eccentrically braced steel frames energy-dissipation behavior and collapse mechanism. Computer program is complied. After this paper applies nonlinear finite element program to analyze the behaviors of eccentrically braced steel frames under cyclic load, the seismic design recommendations of eccentrically brace are presented.


2003 ◽  
Vol 125 (4) ◽  
pp. 393-402 ◽  
Author(s):  
S. A. Karamanos ◽  
E. Giakoumatos ◽  
A. M. Gresnigt

The paper investigates the response of elbows under in-plane bending and pressure, through nonlinear finite element tools, supported by experimental results from real-scale tests. The finite element analysis is mainly based on a nonlinear three-node “tube element,” capable of describing elbow deformation in a rigorous manner, considering geometric and material nonlinearities. Furthermore, a nonlinear shell element from a general-purpose finite element program is employed in some special cases. Numerical results are compared with experimental data from steel elbow specimens. The comparison allows the investigation of important issues regarding deformation and ultimate capacity of elbows, with emphasis on relatively thin-walled elbows. The results demonstrate the effects of pressure and the influence of straight pipe segments. Finally, using the numerical tools, failure of elbows under bending moments is examined (cross-sectional flattening or local buckling), and reference to experimental observations is made.


2012 ◽  
Vol 204-208 ◽  
pp. 1224-1228
Author(s):  
Jun Fen Yang ◽  
Yi Liang Peng ◽  
Xia Bing Wei ◽  
Jin Bo Cui

Tube-plate joint is a frequently-used joint type in steel-tube tower, but the theoretical analysis and experimental investigation on tube-plate joint are absent both at home and abroad. In this paper, the ANSYS finite element program was used to simulate the bearing capacity and deformation condition of tube-plate joint with 1/2-stiffening ring. Eight calculation models were designed, and the width-thickness ratio was changed by changing the width or thickness of stiffening ring. The results indicate that the influence of different width-thickness ratio on tube-plate joint bearing capability is significant. By increasing the width or increasing the thickness of stiffening rings to improve the bearing capacity of the joint is a very effective way.


2007 ◽  
Vol 344 ◽  
pp. 341-348
Author(s):  
Mehmet Ali Pişkin ◽  
Bilgin Kaftanoğlu

Deep-drawing operations are performed widely in industrial applications. It is very important for efficiency to achieve parts with no defects. In this work, a finite element method is developed to simulate deep-drawing operation including wrinkling. A four nodded five degree of freedom shell element is formulated. Isotropic elasto-plastic material model with Von Mises yield criterion is used. By using this shell element, the developed code can predict the bending behavior of workpiece besides membrane behavior. Simulations are carried out with four different element sizes. The thickness strain and nodal displacement values obtained are compared with results of a commercial finite element program and results of previously conducted experiments.


2017 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Boshra Eltaly ◽  
Ahmed Bembawy ◽  
Nageh Meleka ◽  
Kameel Kandil

This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with the specimens filled with normal concrete.


2013 ◽  
Vol 361-363 ◽  
pp. 1259-1263 ◽  
Author(s):  
Jia Lin Xu

In this paper the concrete-filled steel tube concrete arch bridge as the research object, through the finite element program MIDAS, analyzes the internal force of the whole bridge, determined the distribution of internal force and the most unfavorable position; Using the force balance method, taking the reasonable stress of the bending moment status to control goals, determines the boom of the bridge as the condition of reasonable internal force; Use fall down method, according to the reverse sequence in order to cut the boom, each cut as a model for internal force calculation and analysis, get the next will be cut derrick's internal force, its value is the order construction boom of the initial tension.


Author(s):  
Lun Qiu ◽  
Li Lee

The method of pulling a steel catenary riser (SCR) through a steel tube (termed as a pull tube) is common practice for deepwater riser tie back applications. Vortex-induced vibration (VIV) of such a system is complex. VIV analysis programs, such as Shear7 [1], are suitable only for a single, chain-like structure. The application of such a software tool in VIV design of the SCR-pull tube system requires careful consideration of a number of structural and hydrodynamic factors. This paper presents a methodology for VIV analysis of the combined structural system of the SCR with the pull tube. Firstly, the entire SCR-pull tube system is modeled with the finite element program Flexcom [2]. The modes are then calculated for the entire structure with program Modes [3]. Afterwards, the structural nodes are rearranged for VIV analysis with Shear7. The pull tube is secured on the platform through a number of guides on the truss structure of the hull. The diameter of the pull tube is much larger than that of the SCR, and the pull tube is much stiffer in bending than the SCR is. If the entire structure is analyzed with Shear7, the mode for the pull tube (a mode involving a large motion of the pull tube section), which is very high in order, would be embedded in the analysis. It makes sense to single out the pull tube mode for study as if it is the first mode. A computer program, named as V-Span [4] for subsea span VIV analysis, is used to analyze both in-line and cross-flow VIV of the pull tube. A numerical example is presented to demonstrate this methodology. This is a deepwater SCR, which has a diameter of 9 inches. The water depth is 6,300 ft. The pull tube is 640 feet long and 20 inch in diameter. Both the loop-eddy and background currents are analyzed. The fatigue damage resulted from both in-line and cross-flow VIV is estimated.


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