Smart frictional impact energy absorber

2000 ◽  
Vol 5 (2) ◽  
pp. 169-178 ◽  
Author(s):  
A.A.A. Alghamdi
Keyword(s):  
Impact Energy ◽  
Energy Absorber

Modeling and analysis of impact energy absorber by using ls dyna

2015 ◽  
Vol 12 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Adik Yadao ◽  
R. S. Hingole
Keyword(s):  
Impact Energy ◽  
Material Properties ◽  
Research Work ◽  
Cad Model ◽  
Post Processing ◽  
Passenger Compartment ◽  
Efficient Manner ◽  
Energy Absorber ◽  
Modeling And Analysis ◽  
Energy Absorbing

Today’s car is one of the most important things in everyone’s life .Every person wants to have his or her own car but the question that arises in each buyer’s mind is whether the vehicle is safe enough to spend so much of money so it is the responsibility of an mechanical engineer to make the vehical comfortable and at the Same time safer. Now a days automakers are coming with various energy absorbing devices such as crush box, door beams etc. this energy absorbing device s prove to be very useful in reducing the amount force that is being transmitted to the occupant. In this we are using impact energy absorber in efficient manner as compare to earlier. The various steps involved in this project starting from developing the cad model of this inner impact energy absorber using the CAD software CATIA V5 R19. Then pre-processing is carried out in HYPERMESH 11.0 which includes assigning material, properties, boundary conditions such as contacts, constraints etc. LS-DYNA971 is used as a solver and LS-POST is used for the post processing and results obtained are compared to the standards. By carrying out this idea it has been observed that there is a considerable amount of energy that is being absorbed by this energy-absorbing device. Along with this energy absorption, the intrusion in passenger compartment is also reduced by considerable amount. So for safer and comfortable car with inner impact energy absorber is one of the best options available. This will get implement by this research work.

Material Optimization for Design Improvement of Crash Energy Absorbers

2010 ◽  
Author(s):  
Hesham Ibrahim
Keyword(s):  
Impact Energy ◽  
Design Space ◽  
Thickness Distribution ◽  
Optimization Approach ◽  
Optimum Thickness ◽  
Energy Absorber ◽  
Design Improvement ◽  
Material Type ◽  
Thin Walled ◽  
Energy Absorbers

Crash energy absorbers in the form of thin walled tubes play a significant role in mitigating the harmful effects of frontal vehicles accidents on occupants. Specific energy absorbed (SEA), which is the ratio of impact energy absorbed to mass, is usually used to evaluate the efficiency of crash energy absorbers. A good design of a crash energy absorber must maximize the amount of impact energy that can be absorbed with a certain weight. The formal approach that has been used to improve the design of crash energy absorbers is to employ optimization to search for the optimum thickness distribution that maximizes SEA. This approach can be conceptualized as searching the design space in only one dimension (thickness). In this paper, a new dimension is added to the design space (material type). The proposed approach considers the type of material as a variable. An optimum design is then found by not only searching for the optimum thickness distribution, but also by selecting the optimum material type. The approach is demonstrated to the design improvement of a crash energy absorber in the form of a thin walled tube of square cross section. Steel and magnesium have been used as the two material alternatives. Magnesium has been selected due to its low density that had made it a promising candidate for use as a structural material in the automobile manufacturing. The results have shown that following the proposed technique, SEA has been increased by 54% compared to the value obtained through following the formal design optimization approach.

Crash Energy Management of Rotorcraft Seat Based on Limit Load Curves and Corresponding Occupant Pelvic Load

2012 ◽  
Author(s):  
Rasoul Moradi ◽  
Tony Bromwell ◽  
Rohit Jategaonkar ◽  
Hamid M. Lankarani
Keyword(s):  
Impact Energy ◽  
Limit Load ◽  
Spine Injury ◽  
Military Aircraft ◽  
Two Stage ◽  
Energy Absorber ◽  
Load Limit ◽  
Effective Manner ◽  
Energy Absorbing ◽  
The Impact

In military aircraft and helicopter seat design, the seat system must be provided with an energy absorber (EA) to attenuate the acceleration level sustained by the occupants. Because of the limited stroke available for the seat structure, the design of the energy absorber becomes a trade-off problem between the seat stroke and the impact energy absorption. The available stroke must be used to prevent bottoming out of the seat, and also to absorb as much impact energy as possible to protect the occupant. In this study, the energy absorbing systems in civil and military aircraft seat design are evaluated and improved using a mathematical model of the occupant/seat system. Three load-limit design curves, namely, simple EA, two-stage EA, and two-stage EA with initial spike, are modeled, examined, and compared. A model of the load limiter is recommended to minimize the load sustained by the occupant by limiting the relative velocity between the seat pan and the occupant pelvis. Experimental responses of seat system and occupant from literature are utilized to validate the results from this study for civil and military helicopters. A modified energy-absorber/load-limiter is then implemented for the seat structure so that it absorbs the impact energy in an effective manner below the tolerable limit for the occupant and within a minimum stroke. Results from this study indicate that for a designed stroke, the occupant pelvic/lumbar spine injury level is significantly attenuated using the modified energy-absorber system.

Numerical and Experimental Study on Railway Impact Energy Absorption Using Tube External Inversion Mechanism at Real Scale

2006 ◽  
Vol 306-308 ◽  
pp. 315-320 ◽  
Author(s):  
Ign Wiratmaja Puja ◽  
A. Khairullah ◽  
Muhammad Agus Kariem ◽  
A.H. Saputro
Keyword(s):  
Experimental Study ◽  
Numerical Analysis ◽  
Energy Absorption ◽  
Contact Force ◽  
Impact Energy ◽  
Experimental Result ◽  
Energy Absorber ◽  
The Impact ◽  
Inversion Mechanism ◽  
Real Scale

Impact energy and deceleration at a certain time are the most influenced factor to passenger’s safety when collision between railway vehicles occurred. In this paper, forced external inversion mechanism is considered as impact energy absorber. This mechanism is selected due to its constant inversion load along uniform tube [5] and the impact force is reduced because of its inertia effect [7]. Material used as energy absorber is mild steel. Numerical analysis using finite element method is utilized to study the energy absorption capacity and deceleration characteristic of tube external inversion mechanism for complex transient problem of collision. The real scale experimental study is used to validate the numerical analysis by crashing a moving vehicle to static train series where the impact energy absorber module using external inversion mechanism is attached in the tip of static train series. Characteristic that consider in numerical and experimental study are deformation and contact force. The deformation differences between numerical and experimental study are under 9%. Whereas for contact force, the experimental result of contact force disposed under 8% of numerical result for velocity of moving train at 10 and 15 km/h.

scholarly journals Lumbar load attenuation for rotorcraft occupants using a design methodology for the seat impact energy-absorbing system

2012 ◽  
Vol 2 (4) ◽  
Author(s):  
Rasoul Moradi ◽  
Hamid Beheshti ◽  
Hamid Lankarani
Keyword(s):  
Impact Energy ◽  
Vertical Motion ◽  
Spine Injury ◽  
Energy Absorber ◽  
Effective Manner ◽  
Vertical Accelerations ◽  
Safety Considerations ◽  
Energy Absorbing ◽  
The Impact ◽  
Lumbar Load

AbstractAircraft occupant crash-safety considerations require a minimum cushion thickness to limit the relative vertical motion of the seat-pelvis during high vertical impact loadings in crash landings or accidents. In military aircraft and helicopter seat design, due to the potential for high vertical accelerations in crash scenarios, the seat system must be provided with an energy absorber to attenuate the acceleration level sustained by the occupants. Because of the limited stroke available for the seat structure, the design of the energy absorber becomes a trade-off problem between minimizing the stroke and maximizing the energy absorption. The available stroke must be used to prevent bottoming out of the seat as well as to absorb maximum impact energy to protect the occupant. In this study, the energy-absorbing system in a rotorcraft seat design is investigated using a mathematical model of the occupant/seat system. Impact theories between interconnected bodies in multibody mechanical systems are utilized to study the impact between the seat pan and the occupant. Experimental responses of the seat system and the occupant are utilized to validate the results from this study for civil and military helicopters according to FAR 23 and 25 and MIL-S-58095 requirements. A model for the load limiter is proposed to minimize the lumbar load for the occupant by minimizing the relative velocity between the seat pan and the occupant’s pelvis. The modified energy absorber/load limiter is then implemented for the seat structure so that it absorbs the energy of impact in an effective manner and below the tolerable limit for the occupant in a minimum stroke. Results show that for a designed stroke, the level of occupant lumbar spine injury would be significantly attenuated using this modified energy-absorber system.

scholarly journals Experimental and Theoretical Investigation of Combined Expansion Tube-Axial Splitting as Impact Energy Absorbers

2019 ◽  
Vol 20 (02) ◽  
pp. 2050021 ◽  
Author(s):  
Yuwono Budi Pratiknyo ◽  
Rachman Setiawan ◽  
I. Wayan Suweca
Keyword(s):  
Theoretical Investigation ◽  
Impact Energy ◽  
Analytical Calculation ◽  
Impact Testing ◽  
Expansion Tube ◽  
Literature Study ◽  
Energy Absorber ◽  
The Difference ◽  
Axial Splitting ◽  
The Impact

In this study, the combination of an expansion tube and a deformable rigid tube with axial splitting is developed as a new mechanism for use as an impact energy absorber. The impact absorbing structure consists of two circular tube forming dies, with each die allowing the tube to expand and to split. The latter is used to remove away radially the debris after expansion and splitting, so that the absorption process can continue without being obstructed by the debris itself. This paper presents the experimental and theoretical investigation of the combined expansion tube-axial splitting as an impact energy absorber. The experiment by the laboratory scale impact testing has been done with a variation of the parameters such as pipe thickness ([Formula: see text], angle of splitter ([Formula: see text], comparison of dies upgrading diameter ([Formula: see text] and inner pipe diameter ([Formula: see text] ([Formula: see text]/[Formula: see text]. The theoretical investigation is carried out with a literature study related to the mechanics of material and theoretical studies from previous research studies. The final result of this paper, i.e. a new formula proposed to calculate the mean load, is reflective of the study of a combined expansion tube with axial splitting. The difference between the results of analytical calculation and experiments is 10.13%.

Comparing fast inductive tempering and conventional tempering: Effects on microstructure and mechanical properties

2018 ◽  
Vol 115 (4) ◽  
pp. 407 ◽  
Author(s):  
Annika Eggbauer Vieweg ◽  
Gerald Ressel ◽  
Peter Raninger ◽  
Petri Prevedel ◽  
Stefan Marsoner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Energy ◽  
Charpy Impact ◽  
Heat Treating ◽  
Processing Route ◽  
High Heating Rate ◽  
Heating Rates ◽  
High Heating ◽  
Tempering Treatment ◽  
Carbide Distribution

Induction heating processes are of rising interest within the heat treating industry. Using inductive tempering, a lot of production time can be saved compared to a conventional tempering treatment. However, it is not completely understood how fast inductive processes influence the quenched and tempered microstructure and the corresponding mechanical properties. The aim of this work is to highlight differences between inductive and conventional tempering processes and to suggest a possible processing route which results in optimized microstructures, as well as desirable mechanical properties. Therefore, the present work evaluates the influencing factors of high heating rates to tempering temperatures on the microstructure as well as hardness and Charpy impact energy. To this end, after quenching a 50CrMo4 steel three different induction tempering processes are carried out and the resulting properties are subsequently compared to a conventional tempering process. The results indicate that notch impact energy raises with increasing heating rates to tempering when realizing the same hardness of the samples. The positive effect of high heating rate on toughness is traced back to smaller carbide sizes, as well as smaller carbide spacing and more uniform carbide distribution over the sample.

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