Numerical and Experimental Crashworthiness Determination of Aluminum Tube Sections

2014 ◽  
Vol 592-594 ◽  
pp. 1130-1135
Author(s):  
S. Suresh Kumar ◽  
S. Murugappan ◽  
V. Manikanda Balaji
Keyword(s):  
Energy Absorption ◽  
Automobile Industry ◽  
Numerical Technique ◽  
Peak Force ◽  
Automobile Safety ◽  
Design Engineers ◽  
Internal Support ◽  
Aluminum Tubes ◽  
Energy Absorbing ◽  
Crash Characteristics

Generally, vehicle safety is a vital issue in the field of automobile industry. Ensuring the safety of passengers is one of the prime challenges for vehicle design engineers. Automobile safety can be determined from the ability of vehicle structure and its internal support systems to protect the occupants from injuries during an accident. In the present work an attempt has been made to determine the dynamic crash characteristics of hollow aluminum tubes for various impact velocities using numerical technique. Aluminum tubes with diagonal ribs were modeled with and without considering the presence of cracks. Surface cut outs were introduced to verify their influence on energy absorption. One of the important crash parameter peak force experienced by the tubes with rib is compared with tubes without rib. Reduced peak force was observed for the tubes with ribs compared to the ones without ribs, which indicates higher energy absorbing capacity of the tube with the presence of ribs. Significant increase in initial peak force (RF) was noticed with increase of impact velocity. Higher impact energy absorption was noted for a structure with the presence of slit. Experiments were conducted on ribbed hollow tubes and specimens with through hole at the center of the specimen. Results indicate that, ribbed specimens provide significant reduction of peak force compared to bare specimen.

Computational Human Torso Model Validation for Frontal Blunt Trauma

2018 ◽  
Author(s):  
Carolyn E. Hampton ◽  
Michael Kleinberger
Keyword(s):  
Finite Element ◽  
Blunt Trauma ◽  
Energy Absorption ◽  
Elastic Material ◽  
Peak Force ◽  
Tissue Type ◽  
Absorption Data ◽  
Element Analysis ◽  
Material Models ◽  
Torso Model

Recent research on behind-armor blunt trauma (BABT) has focused on the personal protection offered by lightweight armor. A finite element analysis was performed to improve the biofidelity of the US Army Research Laboratory (ARL) human torso model to prepare for simulating blunt chest impacts and BABT. The overly stiff linear elastic material models for the torso were replaced with material characterizations drawn from current literature. FE torso biofidelity was determined by comparing peak force, force-compression, peak compression, and energy absorption data with cadaver responses to a 23.5 kg pendulum impacting at the sternum at 6.7 m/s. Nonlinear foam, viscous foam, soft rubbers, fibrous hyperelastic rubbers, and low moduli elastic material were considered as material models for the flesh, organs, and bones. Simulations modifying one tissue type revealed that the flesh characterization was most crucial for predicting compression and force, followed closely by the organs characterizations. Combining multiple tissue modifications allowed the FE torso to mimic the cadaveric torsos by reducing peak force and increasing chest compression and energy absorption. Limitations imposed by the Lagrangian finite element approach are discussed with potential workarounds described. Proposed future work is split between considering additional impact scenarios accounting for position and biomaterial variability.

scholarly journals Energy Absorption Characteristics of Foam Filled Tri Circular Tube under Bending Loads

2021 ◽  
Vol 15 ◽  
pp. 159-164
Author(s):  
Fauzan Djamaluddin
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Circular Tube ◽  
Comparative Investigation ◽  
Tubular Structures ◽  
Vehicle Engineering ◽  
Bending Resistance ◽  
Bending Loads ◽  
Foam Filled ◽  
Energy Absorbing

In this study, the researcher carried out a comparative investigation of the crashworthy features of different tubular structures with a quasi-static three bending point, like the foam-filled two and tri circular tube structures. Energy absorption capacities and failure modes of different structures are also studied. Furthermore, the general characteristics are investigated and compared for instance the energy absorption, specific energy absorption and energy-absorbing effectiveness for determining the potential structural components that can be used in the field of vehicle engineering. Experimental results indicated that under the bending conditions, the tri foam-filled structures were higher crashworthiness behaviour than the two foam-filled circular structures. Therefore, this study recommended the use of crashworthy structures, such as foam-filled tri circular tubes due to the increased bending resistance and energy-absorbing effectiveness.

scholarly journals Novel cellular materials for energy absorption applications

2020 ◽  
Author(s):  
Mohammed Mudassir ◽  
Mahmoud Mansour
Keyword(s):  
Additive Manufacturing ◽  
Energy Absorption ◽  
Metal Foams ◽  
Cellular Materials ◽  
Cellular Structures ◽  
Senior Project ◽  
Key Factor ◽  
Good Energy ◽  
To Come ◽  
Energy Absorbing

Cellular materials such as metal foams are porous, lightweight structures that exhibit good energy absorption properties. They have been used for many years in various applications including energy absorption. Traditional cellular structures do not have consistent pore sizes and their behaviors and properties such as failure mechanisms and energy absorption are not always same even within the same batch. This is a major obstacle for their applications in critical areas where consistency is required. With the popularity of additive manufacturing, new interest has garnered around fabricating metal foams using this technology. It is necessary to study the possibility of designing cellular structures with additive manufacturing and their energy absorbing behavior before any sort of commercialization for critical applications is contemplated. The primary hypothesis of this senior project is to prove that energy absorbing cellular materials can be designed. Designing in this context is much like how a car can be designed to carry a certain number of passengers. To prove this hypothesis, the paper shows that the geometry is a key factor that affects energy absorption and that is possible to design the geometry in order to obtain certain behaviors and properties as desired. Much like designing a car, it requires technical expertise, ingenuity, experience and learning curve for designing cellular structures. It is simple to come with a design, but not so much when the design in constrained by stringent requirements for energy absorption and failure behaviors. The scope was limited to the study of metal foams such as the ones made from aluminum and titanium. The primary interest has been academic rather than finding ways to commercialize it. The study has been carried out using simulation and experimental verification has been suggested for future work. Nevertheless, the numerical or simulation results show that energy absorbing cellular structures can be designed that exhibit good energy absorption comparable to traditional metal foams but perhaps with better consistency and failure behaviors. The specific energy absorption was found to be 18 kJ/kg for aluminum metal foams and 23 kJ/kg for titanium metal foams. The average crushing force has been observed to be around 70 kN for aluminum and around 190 kN for titanium. These values are within the acceptable range for most traditional metal foams under similar conditions as simulated in this paper.

scholarly journals Reversed-torsion-type crush energy absorption structure and its inexpensive partial-heating torsion manufacturing method based on origami engineering

2021 ◽  
pp. 1-31
Author(s):  
Xilu Zhao ◽  
Chenghai Kong ◽  
Yang Yang ◽  
Ichiro Hagiwara
Keyword(s):  
Energy Absorption ◽  
Peak Load ◽  
Point Of View ◽  
Building Structures ◽  
Manufacturing Method ◽  
Partial Heating ◽  
Vehicle Structure ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
Origami Engineering

Abstract Current vehicle energy absorbers face two problems during a collision in that there is only a 70% collapse in length and there is a high initial peak load. These problems arise because the presently used energy-absorbing column is primitive from the point of view of origami. We developed a column called the Reversed Spiral Origami Structure (RSO), which solves the above two problems. However, in the case of existing technology of the RSO, the molding cost of hydroforming is too expensive for application to a real vehicle structure. We therefore conceive a new structure, named the Reversed Torsion Origami Structure (RTO), which has excellent energy absorption in simulation. We can thus develop a manufacturing system for the RTO cheaply. Excellent results are obtained in a physical experiment. The RTO can replace conventional energy absorbers and is expected to be widely used in not only automobile structures but also building structures.

Robust Design Optimization for Crashworthiness of Vehicle Side Impact

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
Souvik Chakraborty ◽  
Tanmoy Chatterjee ◽  
Rajib Chowdhury ◽  
Sondipon Adhikari
Keyword(s):  
Design Optimization ◽  
New Product Development ◽  
Robust Design ◽  
Automobile Industry ◽  
Human Error ◽  
Differential Evolution Algorithm ◽  
Side Impact ◽  
Robust Design Optimization ◽  
Parameter Uncertainties ◽  
Design Engineers

Optimization for crashworthiness is of vast importance in automobile industry. Recent advancement in computational prowess has enabled researchers and design engineers to address vehicle crashworthiness, resulting in reduction of cost and time for new product development. However, a deterministic optimum design often resides at the boundary of failure domain, leaving little or no room for modeling imperfections, parameter uncertainties, and/or human error. In this study, an operational model-based robust design optimization (RDO) scheme has been developed for designing crashworthiness of vehicle against side impact. Within this framework, differential evolution algorithm (DEA) has been coupled with polynomial correlated function expansion (PCFE). An adaptive framework for determining the optimum basis order in PCFE has also been presented. It is argued that the coupled DEA–PCFE is more efficient and accurate, as compared to conventional techniques. For RDO of vehicle against side impact, minimization of the weight and lower rib deflection of the vehicle are considered to be the primary design objectives. Case studies by providing various emphases on the two objectives have also been performed. For all the cases, DEA–PCFE is found to yield highly accurate results.

Composite Core Cross Tube Crushing Analysis

2020 ◽  
Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam
Keyword(s):  
Energy Absorption ◽  
Compressive Loading ◽  
Deformation Mode ◽  
High Energy ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Layer By Layer ◽  
Thin Walled ◽  
The Cross ◽  
Energy Absorbing

Abstract Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.

Crashworthiness performance of concentric structures with different cross-sectional shapes under multiple loading conditions

2020 ◽  
pp. 095440702096188
Author(s):  
Sadjad Pirmohammad
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Absorption Maximum ◽  
Element Model ◽  
Hexagonal Structure ◽  
Loading Conditions ◽  
Cross Sectional ◽  
Specific Energy Absorption ◽  
Multiple Loading ◽  
Energy Absorbing

This paper evaluates the crashworthiness performance of concentric structures with different numbers of tubes (i.e. one to five) and cross-sectional shapes (i.e. hexagon, octagon, decagon and circle) under the multiple loadings of θ = 0, 10, 20 and 30°. An experimentally validated finite element model generated in LS-DYNA is employed to calculate the crashworthiness parameters including the specific energy absorption, maximum crush force and crush force efficiency. A total of 20 concentric structures are analyzed to explore the effects of number of tubes and cross-sectional shapes on the crushing performance. A multi-criteria decision-making method known as TOPSIS is also used to compare and rank the concentric structures in terms of crushing performance. Based on the results, the hexagonal structure including two tubes and octagonal, decagonal and circular structures including three tubes demonstrate the best results among their corresponding cross-sectional shapes. These structures show 9, 39, 38 and 39% higher specific energy absorption compared to their corresponding single tubal cases, respectively. However, in comparison to single tubal cases, they generate 4, 57, 57 and 58% higher maximum crush force, respectively. As such, the values for the improvement of the crush force efficiency are 3, 26, 25 and 21%, respectively. Furthermore, the decagonal structure including three tubes provides the highest energy absorbing characteristics as compared with all the other structures studied in this research. Meanwhile, taking into account all the multiple loading conditions, this structure shows 50% higher specific energy absorption than the hexagonal structure including single tube (as the weakest structure).

Design of Fiber-Reinforced Composite Tubes as Energy Absorption Element

2009 ◽  
Author(s):  
Y. Yang ◽  
S. Terada ◽  
M. Okano ◽  
A. Nakai ◽  
H. Hamada
Keyword(s):  
Energy Absorption ◽  
High Energy ◽  
Fiber Reinforced ◽  
Inertia Moment ◽  
Reinforced Composite ◽  
Bending Behavior ◽  
High Energy Absorption ◽  
Energy Absorbing ◽  
Frp Tubes ◽  
Two Sides

As an energy absorption member, fiber-reinforced composites (FRPs) are more favorable because they are light in weight and possess better energy absorption capabilities as compared to their metal counterparts. However, the energy absorbing mechanisms of FRP are complicated owning to the multi-micro fractures. Therefore, in this study, the designs of FRP tubes were carried out with considerations directed at the energy absorbing mechanisms. Two methods based on the design of the energy absorbed by bending of the fronds (Ubend) and the energy absorbed by fiber fractures (Uff) are concentrated. Here the bending behavior of frond can be considered as the bending beam by an external force. And it is found that Ubend is affected directly by the inertia moment I, which is affect by the geometry. Therefore, FRP tubes were fabricated to have a geometry combined with a bigger I. Additional, in order to get more fiber fractures to get an increased Uff, the design of bending stress, σ, was carried out. FRP tubes bending towards one side only rather than two sides are proposed to get bending fronds with a double thicker thickness, which in turn led to high stresses, many fiber fractures and high energy absorption.

scholarly journals Dynamic Compressive Behaviors of Two-Layer Graded Aluminum Foams under Blast Loading

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1445 ◽  
Author(s):  
Minzu Liang ◽  
Xiangyu Li ◽  
Yuliang Lin ◽  
Kefan Zhang ◽  
Fangyun Lu
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Blast Resistance ◽  
Blast Loading ◽  
Deformation Energy ◽  
Aluminum Foams ◽  
Conflicting Objectives ◽  
Energy Dissipated ◽  
Transmitted Impulse ◽  
Energy Absorbing

Experimental and numerical analyses were carried out to reveal the behaviors of two-layer graded aluminum foam materials for their dynamic compaction under blast loading. Blast experiments were conducted to investigate the deformation and densification wave formation of two-layer graded foams with positive and negative gradients. The shape of the stress waveform changed during the propagation process, and the time of edge rising was extended. Finite element models of two-layer graded aluminum foam were developed using the periodic Voronoi technique. Numerical analysis was performed to simulate deformation, energy absorption, and transmitted impulse of the two-layer graded aluminum foams by the software ABAQUS/Explicit. The deformation patterns were presented to provide insights into the influences of the foam gradient on compaction wave mechanisms. Results showed that the densification wave occurred at the blast end and then gradually propagated to the distal end for the positive gradient; however, compaction waves simultaneously formed in both layers and propagated to the distal end in the same direction for the negative gradient. The energy absorption and impulse transfer were examined to capture the effect of the blast pressure and the material gradient. The greater the foam gradient, the more energy dissipated and the more impulse transmitted. The absorbed energy and transferred impulse are conflicting objectives for the blast resistance capability of aluminum foam materials with different gradient distributions. The results could help in understanding the performance and mechanisms of two-layer graded aluminum foam materials under blast loading and provide a guideline for effective design of energy-absorbing materials and structures.

The Energy Absorption Characteristics of Square Mild Steel Tubes With Multiple Induced Circular Hole Discontinuities—Part I: Experiments

2009 ◽  
Vol 76 (4) ◽  
Author(s):  
S. B. Bodlani ◽  
S. Chung Kim Yuen ◽  
G. N. Nurick
Keyword(s):  
Mild Steel ◽  
Energy Absorption ◽  
Circular Hole ◽  
Progressive Collapse ◽  
Experimental Tests ◽  
Absorption Capacity ◽  
Peak Force ◽  
Steel Tubes ◽  
Initial Peak ◽  
Absorption Characteristics

This two-part article reports the results of experimental and numerical works conducted on the energy absorption characteristics of thin-walled square tubes with multiple circular hole discontinuities. Part I presents the experimental tests in which dynamic and quasistatic axial crushings are performed. The mild steel tubes are 350 mm in length, 50 mm wide, and 1.5 mm thick. Circular hole discontinuities, 17 mm in diameter, are laterally drilled on two or all four opposing walls of the tube to form opposing hole pairs. The total number of holes varies from 2 to 10. The results indicate that the introduction of holes decreases the initial peak force but an increase in the number of holes beyond 2 holes per side does not further significantly decrease the initial peak force. The findings show that strategic positioning of holes triggers progressive collapse hence improving energy absorption. The results also indicate that the presence of holes may at times disrupt the formation of lobes thus compromising the energy absorption capacity of the tube. In Part II, the finite element package ABAQUS/EXPLICIT version 6.4–6 is used to model the dynamic axial crushing of the tubes and to investigate the action of the holes during dynamic loading at an impact velocity of 8 m/s.

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