Study of the Stick-Slip Transition of Newton’s Cradle With Friction

Author(s):  
Adrian Rodriguez ◽  
Alan Bowling

This work uses a new discrete approach to analyze the stick-slip transition of Newton’s cradle with frictional contact. The consideration of friction here leads to a simultaneous, multiple point, indeterminate collision. This work strictly adheres to the assumptions of rigid body modeling in conjunction with the notion that the configuration of the system are constant in the short time span of the collision, which enforces a kinematic relationship between the impact points. The post-impact velocities are determined by using the work-energy relationship of a collision and an energetic coefficient of restitution (ECOR) to model energy dissipation. A three and six degree-of-freedom (DOF) model of the system is considered in this work to examine the stick-slip transition and simulate the post-impact behavior. Simulations are conducted for each model using different coefficients of friction (COFs). The results obtained are compared to theoretical and experimental results reported in other works.

Author(s):  
Abhishek Chatterjee ◽  
Alan Bowling

This work presents a new approach for resolving the unique invariant slip direction at Stick-Slip Transition during impact. The solution method presented in this work is applicable to both single-point and multi-point impact problems. The proposed method utilizes rigid body constraints to resolve the impact forces at all collision points in terms of a single independent impact forces parameter. This work also uses an energetic coefficient of restitution to terminate impact events, thereby yielding energetically consistent post-impact behavior.


Author(s):  
Adrian Rodriguez ◽  
Alan Bowling

This work analyzes the effects of the stick-slip transition of planar rigid body systems undergoing simultaneous, multiple point impact with Coulomb friction. A discrete, algebraic approach is used in conjunction with an event-driven scheme which detects impact events. The system equations of motion for the examples considered are indeterminate with respect to the impact forces. Constraints consistent with rigid body assumptions are implemented to overcome the indeterminacy. The post-impact velocities of a system are determined by exploiting the work-energy relationship of a collision and using an energetic coefficient of restitution to model energy dissipation. These developments lead to a unique and energetically consistent solution to the post-impact velocities. A frictionless rocking block example is analyzed as a benchmark case and compared to experimental results to demonstrate the accuracy of the proposed method. Simulation results are also presented for a planar ball example with friction.


Author(s):  
Helio A. Navarro ◽  
Jose M. Balthazar ◽  
Reyolando M. L. R. F. Brasil

This work analyses the post impact behavior of a mechanical system consisting of an oscillator and an unbalanced non–ideal electrical motor. The impact between the mechanical system and a rigid wall is based on the assumption that the impacting bodies undergo local deformations. The method used in the present work is similar to the Discrete Element Method for particle systems modeled with a “soft–sphere” mechanism. The contact forces are modeled using a nonlinear damped Hertzian Spring-Dashpot system. The mathematical model of the mechanical system is represented by a set of nonlinear ordinary differential equations. The transient and steady-state responses are discussed. As the motor is considered a non ideal energy source, the Sommerfeld effect is also analyzed. The impact model is first applied for a single freely falling particle and then in the proposed mechanical system. Non-dimensional expressions for the contact force and numerical simulations of the mechanical system behavior are also presented.


2017 ◽  
Vol 49 (1) ◽  
pp. 198-205 ◽  
Author(s):  
S. Yan ◽  
L. Y. Guo ◽  
J. Y. Zhao ◽  
X. M. Lu ◽  
T. Zeng ◽  
...  

Author(s):  
Adrian Rodriguez ◽  
Abhishek Chatterjee ◽  
Alan Bowling

This work analyzes three-dimensional multibody systems undergoing indeterminate contact and impact in the presence of Coulomb friction. A discrete approach is used to analyze the impact behavior upon detection of the impact events during simulation. During an impact event, the velocities of the impact points describe the systems state and can be studied to characterize the nature of impact and determine the post-impact behavior of the system. The velocities of the impact points during an impact event can be described in terms of the impulses at those points. This work uses Amontons-Coulombs law of friction and rigid body constraints to develop a technique for reducing the number of impulses required to compute the velocities of the impact point during the impact event. Indeterminacies associated with slip direction arise, when Coulombs friction is considered. Therefore, a numerical approach is used to evolve the slip direction along with the slip velocity, with respect to a normal impulse. The work-energy theorem is used to detect the end of the impact event, and determine the post-impact velocities of the system. Examples of a three-dimensional rocking block and a sphere impacting a corner are analyzed to demonstrate the proposed methodology.


2021 ◽  
pp. 109963622199387
Author(s):  
Mathilde Jean-St-Laurent ◽  
Marie-Laure Dano ◽  
Marie-Josée Potvin

The effect of extreme cold temperatures on the quasi-static indentation and the low velocity impact behavior of woven carbon/epoxy composite sandwich panels with Nomex honeycomb core was investigated. Impact tests were performed at room temperature, –70°C, and –150°C. Two sizes of hemispherical impactor were used combined to three different impactor masses. All the impact tests were performed at the same initial impact velocity. The effect of temperature on the impact behavior is investigated by studying the load history, load-displacement curves and transmitted energy as a function of time curves. Impact damage induced at various temperatures was studied using different non-destructive and destructive techniques. Globally, more damages are induced with impact temperature decreasing. The results also show that the effect of temperature on the impact behavior is function of the impactor size.


Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.


2021 ◽  
Vol 60 (1) ◽  
pp. 145-157
Author(s):  
Yi Luo ◽  
Ke Yuan ◽  
Lumin Shen ◽  
Jiefu Liu

Abstract In this study, a series of in-plane hexagonal honeycombs with different Poisson's ratio induced by topological diversity are studied, considering re-entrant, semi-re-entrant and convex cells, respectively. The crushing strength of honeycomb in terms of Poisson's ratio is firstly presented. In the previous research, we have studied the compression performance of honeycomb with different negative Poisson's ratio. In this study, a comparative study on the local impact resistance of different sandwich panels is conducted by considering a spherical projectile with low to medium impact speed. Some critical criteria (i.e. local indentation profile, global deflection, impact force and energy absorption) are adopted to analyze the impact resistance. Finally, an influential mechanism of Poisson's ratio on the local impact resistance of sandwich panel is studied by considering the variation of core strength and post-impact collapse behavior.


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