Resolving the Unique Invariant Slip-Direction in Rigid Three-Dimensional Multi-Point Impacts at Stick-Slip Transitions

2018 ◽  
Author(s):  
Abhishek Chatterjee ◽  
Alan Bowling
Keyword(s):  
Single Point ◽  
Three Dimensional ◽  
Impact Behavior ◽  
Slip Direction ◽  
Stick Slip ◽  
Impact Forces ◽  
Post Impact ◽  
Impact Problems ◽  
Slip Transition ◽  
The Impact

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.

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

2013 ◽  
Author(s):  
Adrian Rodriguez ◽  
Alan Bowling
Keyword(s):  
Impact Behavior ◽  
Multiple Point ◽  
Stick Slip ◽  
Kinematic Relationship ◽  
Short Time Span ◽  
Post Impact ◽  
Newton’S Cradle ◽  
Six Degree Of Freedom ◽  
Slip Transition ◽  
The Impact

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.

Solution to Three-Dimensional Indeterminate Contact and Impact With Friction Using Rigid Body Constraints

2015 ◽  
Author(s):  
Adrian Rodriguez ◽  
Abhishek Chatterjee ◽  
Alan Bowling
Keyword(s):  
Rigid Body ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Impact Behavior ◽  
Impact Event ◽  
Slip Direction ◽  
Rocking Block ◽  
Post Impact ◽  
Contact And Impact ◽  
The Impact

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.

Mechanical Aspects of the Dynamic Tear Test

1969 ◽  
Vol 91 (3) ◽  
pp. 535-543 ◽  
Author(s):  
G. E. Nash ◽  
E. A. Lange
Keyword(s):  
Crack Initiation ◽  
Bending Moments ◽  
Simple Analysis ◽  
Transverse Beam ◽  
Fracture Characteristics ◽  
Impact Forces ◽  
Impact Problems ◽  
The Impact

The impact forces and specimen bending moments generated during the NRL dynamic tear test are interpreted in terms of the dynamics of the system and the fracture characteristics of the material. It is shown that the impact forces and bending moments up to the time of crack initiation can be predicted using a simple analysis based on Timoshenko’s treatment of transverse beam impact problems. This implies the possibility of using this analysis for dynamic KIc determinations.

Vibrations due to Impact in a Non Ideal Mechanical System With a Non-Linear Hertzian Contact Model

2014 ◽  
Author(s):  
Helio A. Navarro ◽  
Jose M. Balthazar ◽  
Reyolando M. L. R. F. Brasil
Keyword(s):  
Mechanical System ◽  
Rigid Wall ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Impact Behavior ◽  
Steady State Responses ◽  
Post Impact ◽  
The Impact ◽  
The Mathematical Model ◽  
State Responses

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.

scholarly journals Jumping with adhesion: landing surface incline alters impact force and body kinematics in crested geckos

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Timothy E. Higham ◽  
Mara N. S. Hofmann ◽  
Michelle Modert ◽  
Marc Thielen ◽  
Thomas Speck
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Three Dimensional ◽  
Adhesive System ◽  
Vertical Surface ◽  
High Impact ◽  
Body Movements ◽  
Impact Forces ◽  
Landing Platform ◽  
The Impact

AbstractArboreal habitats are characterized by a complex three-dimensional array of branches that vary in numerous characteristics, including incline, compliance, roughness, and diameter. Gaps must often be crossed, and this is frequently accomplished by leaping. Geckos bearing an adhesive system often jump in arboreal habitats, although few studies have examined their jumping biomechanics. We investigated the biomechanics of landing on smooth surfaces in crested geckos, Correlophus ciliatus, asking whether the incline of the landing platform alters impact forces and mid-air body movements. Using high-speed videography, we examined jumps from a horizontal take-off platform to horizontal, 45° and 90° landing platforms. Take-off velocity was greatest when geckos were jumping to a horizontal platform. Geckos did not modulate their body orientation in the air. Body curvature during landing, and landing duration, were greatest on the vertical platform. Together, these significantly reduced the impact force on the vertical platform. When landing on a smooth vertical surface, the geckos must engage the adhesive system to prevent slipping and falling. In contrast, landing on a horizontal surface requires no adhesion, but incurs high impact forces. Despite a lack of mid-air modulation, geckos appear robust to changing landing conditions.

scholarly journals Effect of Braiding Angle on the Impact and Post-Impact Behavior of 3D Braided Composites

2017 ◽  
Vol 49 (1) ◽  
pp. 198-205 ◽  
Author(s):  
S. Yan ◽  
L. Y. Guo ◽  
J. Y. Zhao ◽  
X. M. Lu ◽  
T. Zeng ◽  
...  
Keyword(s):  
Impact Behavior ◽  
Braided Composites ◽  
3D Braided Composites ◽  
Post Impact ◽  
Braiding Angle ◽  
The Impact

The Analysis and Application of Numerical Wave Tank Based on the Viscous Fluid

2010 ◽  
Author(s):  
Lei Yue ◽  
Zhiguo Zhang ◽  
Dakui Feng
Keyword(s):  
Three Dimensional ◽  
Wave Generation ◽  
Green Water ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Water On Deck ◽  
Impact Forces ◽  
Numerical Wave ◽  
The Impact ◽  
Shipping Water

The so-called numerical wave tank is to use a mathematical model to simulate the process of making waves and interaction between waves and structures. Shipping water occurs when the wave height exceeds the deck level of a floating vessel. A large amount of seawater flows down onto the deck. It damages deck equipment and causes even submergence. The water on deck is called “Green Water”, and it is dangerous for ships. It is of great significance to analyze and simulate wave and green water phenomenon. This paper developed a three-dimensional numerical wave tank and presented VOF method to deal with the movement with free surface, and then simulated process of wave generation numerically. A two-dimensional numerical simulation of the green water phenomenon of a hull placed in regular wave was performed. The process of wave running up and wave deforming were obtained. The results show that the present numerical scheme and methods can be used to simulate process of wave generation and phenomenon of green water on deck, and to predict and analyze the impact forces between waves and structures due to green water.

The Theories and Application of Numerical Simulation with Smoothed Particle Hydrodynamics Method

2012 ◽  
Vol 531-532 ◽  
pp. 695-698
Author(s):  
Hui Lin Zhou ◽  
Hui Yong Yu ◽  
Ming Hua Pang
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Three Dimensional ◽  
Hypervelocity Impact ◽  
Particle Model ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Impact Problems ◽  
Numerical Calculation Method ◽  
The Impact

The Smoothed Particle Hydrodynamics (SPH) method is a very important method to resolve hypervelocity problems and the basic theory of SPH method is introduced here. Then the three dimensional hypervelocity impact problems are simulated by using the model of chair. The results of SPH analysis show that (SPH) method is a numerical calculation method to resolve hypervelocity problems without mesh model but the particle model must be getting to calculate and the program code is less than other method. By analysis the results of the simulation is reasonable and very similar to the test result. It can be concluded that the advantages of SPH demonstrated make it a good and an ideal method to simulate the impact problem and other problems.

The Efficacy of the Momentum Balance Method in Transverse Impact Problems

1998 ◽  
Vol 120 (1) ◽  
pp. 47-53 ◽  
Author(s):  
A. S. Yigit ◽  
A. P. Christoforou
Keyword(s):  
Permanent Deformation ◽  
Local Deformation ◽  
Balance Method ◽  
Impact Behavior ◽  
Momentum Balance ◽  
Transverse Impact ◽  
Balance Solution ◽  
Post Impact ◽  
The Difference ◽  
Impact Problems

An elastic-plastic contact law that incorporates local permanent deformation in the contact zone has been used to investigate the efficacy of the momentum balance method in transverse impact problems. The momentum balance solution is compared to the numerical solution of the same equations using the contact law. It is shown that the momentum balance method gives very good results for the post impact behavior of both the impacter and the beam. In certain cases, it is also shown to yield satisfactory results for the dynamic behavior during contact. It is demonstrated that the momentum balance method with an appropriate coefficient of restitution obtained from the contact law, is physically the same as using the contact law itself, with the difference that the local deformation is neglected.

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