scholarly journals Parameters Optimization and Energy Absorption Evaluation of the Steel Ball Friction Energy Absorber

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Bin Gong
Keyword(s):  
Energy Absorption ◽  
Contact Force ◽  
Column Height ◽  
Load Factor ◽  
Column Diameter ◽  
Impact Frequency ◽  
Energy Absorber ◽  
Ball Diameter ◽  
The Impact ◽  
Dynamic Load Factor

The energy absorber is used to simulate the reaction of a working piece subjected to a vibration stimulus, by which the consistent and repeatable reactions to the tool’s vibration inputs could be achieved. According to the proposed coupling simulation model by using commercial software RecurDyn and EDEM, the energy dissipated by the energy absorber and the contact force between the drill rod and the piston are evaluated under different load conditions such as the impact frequency and impact stroke. Moreover, the effects of the ball diameter, ball column height, and diameter on the energy absorption characteristics are also studied. The results show that the impact frequency and stroke influence the energy absorber by changing the impact force; the energy absorption is more obvious under higher impact frequency and long impact stroke. The filling ball diameter influences the energy reflectivity by changing the porosity, which is negatively correlated to the energy reflectivity, and a 6 mm filling ball diameter is suggested. The energy reflectivity is inversely proportional to the ball column height and diameter, and the suggested ball column diameter and height are 160 mm and 600 mm, respectively, with energy reflectivity of 0.045. Even when the increase in impact frequency and stroke will increase the contact force, the dynamic load factor decreases. The contact force and dynamic load factor are inversely proportional to the ball column height, but they are not influenced by the ball diameter and the ball column diameter.

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.

Effect of Parameter Optimization of Contact Force Models on the Impact Dynamic Responses

1993 ◽  
Author(s):  
H. M. Lankarani ◽  
F. Wu
Keyword(s):  
Energy Absorption ◽  
Contact Force ◽  
Multibody System ◽  
High Energy ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Particle Model ◽  
Force Model ◽  
High Energy Absorption ◽  
The Impact

Abstract Reducing the severity of an impact to a structure or a multibody system is a significant aspect of engineering design. This requires the knowledge of variations of the resulting contact forces and also how these contact forces can be reduced. This paper presents an optimization methodology for the selection of proper parameters in the contact/impact force models so as to minimize the maximum value of the contact force. A two-particle model of an impact between two solids is considered, and then generalized to the impact analysis between two bodies of a multibody system. The concept of effective mass is presented in order to compensate for the effect of joint forces or impulses. The system is reduced to a single degree-of-freedom mass-spring-damper vibro-impact system. A single differential equation of motion in the direction of relative indentation of local contact surfaces is derived. Different contact force models of hysteresis form including linear and nonlinear models are described. An optimization problem is then formulated and solved by using the method of modified feasible direction for constrained minimization. A numerical integrator is used at every design iteration to obtain the system dynamic response for a given set of design variables. The objective function is to minimize the peak acceleration of the system equivalent mass resulting from the contact force. Comparison of the system with optimal parameters and non-optimal one shows that the peak contact force is greatly reduced for the optimal one. Since these parameters reflect the material properties (stiffness and damping) of the impacting bodies or surfaces, suitable materials may then be selected based upon the information provided by this optimization procedure. It is observed that the materials, which have good crashworthiness properties should posses capability of dissipating impact energy both in the forms of permanent indentation and internal damping friction. Based upon the analysis of the impact responses, mechanism of energy dissipation, and the typical force-indentation diagram for the high energy absorption materials obtained from experiments, a new contact force model is proposed which could precisely describe the impact response of high energy-absorption materials.

Hoisting Dynamics Analysis of Suspended Access Equipment

2010 ◽  
Vol 163-167 ◽  
pp. 708-712
Author(s):  
Xi Jian Zheng ◽  
Zhen Lu ◽  
Zheng Yi Xie ◽  
Yan Hong
Keyword(s):  
Impact Load ◽  
Load Factor ◽  
Acceleration Response ◽  
Response Curves ◽  
Load Effect ◽  
Structure Dynamics ◽  
Mechanics Model ◽  
Dynamics Response ◽  
The Impact ◽  
Dynamic Load Factor

Suspended access equipment (SAE) is widely used and the impact load effect on the structure of SAE while hoisting from the ground is to be researched. In the paper, three methods were taken to analyze hoisting dynamics response of SAE, including energy equation method, mechanics model calculation and finite element method (FEM), and it turns out that FEM is the perfect one. By using FEM, structure dynamics response curve and dynamic load factor were obtained. The effect factors of structure dynamics response were also analyzed. Measures were given finally to improve the effect of hoisting impact load by analyzing displacement and acceleration response curves of SAE.

The Effect of Gaps on the Impact Response of a Cask Closure Lid

2009 ◽  
Author(s):  
Gordon S. Bjorkman
Keyword(s):  
Dynamic Model ◽  
Nonlinear Function ◽  
Elastic Behavior ◽  
Load Factor ◽  
Spent Fuel ◽  
Element Analysis ◽  
Equivalent Mass ◽  
Leak Tightness ◽  
The Impact ◽  
Dynamic Load Factor

During an impact event, gaps between the various components of a spent fuel transportation cask may create secondary impacts that result in higher dynamic loads than would have occurred if the gaps had not been present. A condition of particular interest is the gap that may exist between the cask internal contents (fuel assemblies) and cask closure lid, and the effect this gap may have on amplifying the response of the closure lid during an impact. Through the use of a simple dynamic model this paper investigates the effect of a secondary impact due to a gap between the cask internals and the cask closure lid on the response of the closure lid during a 30 foot end drop. The dynamic model consists of five components: (1) The equivalent mass of the internal contents, (2) the gap between the contents and cask lid, (3) the stiffness of the cask lid, assumed to be a simply supported circular plate, (4) the equivalent mass of the lid and finally, (5) an impact limiter that applies a constant deceleration force to the cask overpack during impact. In addition, the dynamic model assumes elastic behavior. This is consistent with the Standard Review Plan (NUREG-1617), which recommends that the closure lid bolts and closure lid system within the region of the lid bolts remain elastic in order to demonstrate leak-tightness by finite element analysis. The response results are presented in terms of the Dynamic Load Factor (DLF) for the closure lid. Response is shown to be a nonlinear function of the impact limiter deceleration, gap size and closure lid diameter, thickness and inertial properties. These results provide valuable insights into the parameters that affect response and show the conditions under which gaps of sufficient size may significantly influence response.

A Numerical Model to Study the Effects of Aluminum Foam Filler on the Dynamic Behavior of a Steel Tubular Energy Absorber Using a Multi-Node Displacement Evaluation Procedure

2014 ◽  
Vol 9 (3) ◽  
Author(s):  
Vinícius Veloso ◽  
Pedro Américo Almeida Magalhães ◽  
Janes Landre
Keyword(s):  
Numerical Model ◽  
Dynamic Behavior ◽  
Energy Absorption ◽  
Great Influence ◽  
Constant Load ◽  
Absorption Efficiency ◽  
Evaluation Procedure ◽  
Energy Absorber ◽  
Energy Absorption Efficiency ◽  
The Impact

Tubular energy absorbers are usually found in the structures of cars, trains, and other means of transportation. They can absorb high levels of impact energy by plastic deformation during axial folding. The key advantages of this type of energy absorber are the compact dimensions, simple manufacturing, and good energy absorption efficiency. The dynamic behavior of the tube during collapse has a great influence on the total energy absorbed and, consequently, the force transmitted during folding. The optimization of this process may lead to improved energy absorption efficiency, allowing us to reduce the dimensions and costs of the component or improve the crashworthiness of pre-existing structures. Foam materials are used in most applications to improve the impact absorption of structures due to its constant load pattern during crushing. They are used, in most cases, as fillers inside empty absorbers such as tubes. In this paper, a numerical model was developed in order to study the possible interactions of foam and tube walls, providing information onhow this relation can influence the deformation modes of the tube. The obtained results showed a direct influence of the foam interaction with the tube walls under the energy absorption and load transmitting characteristics of the component.

Crashworthiness Study of Helicopter Skid Landing Gear System Equipped With a Magnetorheological Energy Absorber

2017 ◽  
Author(s):  
Muftah Saleh ◽  
Ramin Sedaghati ◽  
Rama Bhat
Keyword(s):  
Energy Absorption ◽  
Landing Gear ◽  
Civil Aviation ◽  
Soft Landing ◽  
Damping Force ◽  
Dimensional Solution ◽  
Energy Absorber ◽  
Passive Damper ◽  
Skid Landing Gear ◽  
The Impact

The present study concerns with the performance of a skid landing gear (SLG) system of a rotorcraft impacting the ground at a vertical sink rate of 5.0 m/s. The impact attitude is per chapter 527 of the Airworthiness Manual (AWM) of Transport Canada Civil Aviation and FAR Part 27 of the U.S. Federal Aviation Regulation. A single degree of freedom helicopter model is investigated under two rotor lift factors 0.67 and 1.0. Three Configurations are evaluated: a) A conventional SLG; b) SLG equipped with a passive viscous damper and c) SLG incorporated with a magnetorheological energy absorber. The non-dimensional solutions of the helicopter model show that the passive damper system could reduce the maximum acceleration experienced by the helicopter occupants by 21% and 19.8% in comparison to the undamped system for the above rotor lift factors, respectively. However, the passive damper fails to constrain the non-dimensional energy absorption stroke of the damper within the given 18 cm maximum stroke and a bottoming out of the damper piston was noticed. Therefore, the alternative and successful choice was to employ a magnetorheological energy absorber (MREA). To improve the MREA controllability and to resettle the payload with no oscillations, i.e. in one cycle, two different Bingham numbers for compression stroke and rebound stroke were defined in the non-dimensional solution. Several simulations were conducted for different values of Bingham numbers. Among these numerical simulation results, the solution that implemented the optimum Bingham numbers was found to be the only one feasible solution. In this case the MREA with optimum Bingham number for compression could utilize the full energy absorption stroke to attain soft landing. In the rebound stroke, the generated optimal on-state damping force successfully controls the bounce of the payload until the payload settles down to its original equilibrium position with no oscillations.

scholarly journals Study on improvement of prefolded energy absorption device to constant resistance and its mechanical properties

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110368
Author(s):  
Dong An ◽  
Jiaqi Song ◽  
Hailiang Xu ◽  
Jingzong Zhang ◽  
Yimin Song ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Compression Test ◽  
Side Wall ◽  
Concave Side ◽  
Displacement Curve ◽  
Static Compression ◽  
Constant Resistance ◽  
The Impact ◽  
Force Displacement

When the rock burst occurs, energy absorption support is an important method to solve the impact failure. To achieve constant resistance performance of energy absorption device, as an important component of the support, the mechanical properties of one kind of prefolded tube is analyzed by quasi-static compression test. The deformation process of compression test is simulated by ABAQUS and plastic strain nephogram of the numerical model are studied. It is found that the main factors affecting the fluctuation of force-displacement curve is the stiffness of concave side wall. The original tube is improved to constant resistance by changing the side wall. The friction coefficient affects the folding order and form of the energy absorbing device. Lifting the concave side wall stiffness can improve the overall stiffness of energy absorption device and slow down the falling section of force-displacement curve. It is always squeezed by adjacent convex side wall in the process of folding, with large plastic deformation. Compared with the original one, the improved prefolded tube designed in this paper can keep the maximum bearing capacity ( Pmax), increase the total energy absorption ( E), improve the specific energy absorption (SEA), and decrease the variance ( S2) of force-displacement curve.

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

Dynamic Axial Compression of Square CFRP/Aluminium Tubes

2019 ◽  
Vol 794 ◽  
pp. 202-207
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Jeong Whan Yoon ◽  
Zhan Yuan Gao
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Fibre Composite ◽  
Dynamic Tests ◽  
Carbon Fibre Composite ◽  
Specific Energy Absorption ◽  
Static Tests ◽  
Crushing Force ◽  
Cfrp Tubes ◽  
The Impact

Carbon fibre composite tubes have high strength to weight ratios and outstanding performance under axial crushing. In this paper, square CFRP tubes and aluminium sheet-wrapped CFRP tubes were impacted by a drop mass to investigate the effect of loading velocity on the energy absorption of CFRP/aluminium tubes. A comparison of the quasi-static and dynamic crushing behaviours of tubes was made in terms of deformation mode, peak crushing force, mean crushing force, energy absorption and specific energy absorption. The influence of the number of aluminium layers that wrapped square CFRP tubes on the crushing performance of tubes under axial impact was also examined. Experimental results manifested similar deformation modes of tubes in both quasi-static and dynamic tests. The dynamic peak crushing force was higher than the quasi-static counterpart, while mean crushing force, energy absorption and specific energy absorption were lower in dynamic tests than those in quasi-static tests. The mean crushing force and energy absorption decreased with the crushing velocity and increased with the number of aluminium layers. The impact stroke (when the force starts to drop) decreased with the number of aluminium layers.

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