The Impact Dynamics of Space Net Based on Hertzian Model

2021 ◽  
pp. 981-994
Author(s):  
Zhen Ming ◽  
Yang Leping ◽  
Zhu Yanwei ◽  
Huang Huan
Keyword(s):  
Impact Dynamics ◽  
The Impact

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

scholarly journals The role of drop shape in impact and splash

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qingzhe Liu ◽  
Jack Hau Yung Lo ◽  
Ye Li ◽  
Yuan Liu ◽  
Jinyu Zhao ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Spherical Geometry ◽  
Impact Dynamics ◽  
Helmholtz Instability ◽  
Liquid Drops ◽  
Drop Shape ◽  
Spreading Dynamics ◽  
Solid Substrates ◽  
The Impact

AbstractThe impact and splash of liquid drops on solid substrates are ubiquitous in many important fields. However, previous studies have mainly focused on spherical drops while the non-spherical situations, such as raindrops, charged drops, oscillating drops, and drops affected by electromagnetic field, remain largely unexplored. Using ferrofluid, we realize various drop shapes and illustrate the fundamental role of shape in impact and splash. Experiments show that different drop shapes produce large variations in spreading dynamics, splash onset, and splash amount. However, underlying all these variations we discover universal mechanisms across various drop shapes: the impact dynamics is governed by the superellipse model, the splash onset is triggered by the Kelvin-Helmholtz instability, and the amount of splash is determined by the energy dissipation before liquid taking off. Our study generalizes the drop impact research beyond the spherical geometry, and reveals the potential of using drop shape to control impact and splash.

A Study on Using Plasticity Theory in the Design of the Transit Platform’s Panel

2012 ◽  
Vol 591-593 ◽  
pp. 148-151
Author(s):  
Yuan Yuan Teng ◽  
Da Shan Dong ◽  
Hui Qing Qiu
Keyword(s):  
Design Theory ◽  
Impact Dynamics ◽  
Practical Situation ◽  
Theoretical Derivation ◽  
Container Crane ◽  
Starting Point ◽  
Reference Design ◽  
The Impact ◽  
Energy Law ◽  
Full Consideration

Taking the limit intensity as a starting point, a plasticity design theory is introduced in the design of the transit platform’s panel of double trolley quayside container crane for replacing elasticity design theory as a conventional method. As to the impact dynamics issue, the study gives a theoretical derivation based on the energy law as well as a verification of the experiments of the lockpins’ falling , and uses simulations with Ansys/Ls-dyna condition. Combining the above three aspects, the results prove to be correct. Given the limitations and requirements of the practical situation and the standards, a reasonable design is offered. Through full consideration, it provides the value of the experience for future reference design and should be widely extended to use.

scholarly journals Lifting a sessile oil drop from a superamphiphobic surface with an impacting one

2020 ◽  
Vol 6 (34) ◽  
pp. eaba4330
Author(s):  
Olinka Ramírez-Soto ◽  
Vatsal Sanjay ◽  
Detlef Lohse ◽  
Jonathan T. Pham ◽  
Doris Vollmer
Keyword(s):  
Surface Tension ◽  
Energy Transfer ◽  
Impact Velocity ◽  
Sessile Drop ◽  
Cloud Formation ◽  
Impact Dynamics ◽  
Combustion Engines ◽  
Intrinsic Properties ◽  
Natural Processes ◽  
The Impact

Colliding drops are encountered in everyday technologies and natural processes, from combustion engines and commodity sprays to raindrops and cloud formation. The outcome of a collision depends on many factors, including the impact velocity and the degree of alignment, and intrinsic properties like surface tension. Yet, little is known on binary impact dynamics of low-surface-tension drops on a low-wetting surface. We investigate the dynamics of an oil drop impacting an identical sessile drop sitting on a superamphiphobic surface. We observe five rebound scenarios, four of which do not involve coalescence. We describe two previously unexplored cases for sessile drop liftoff, resulting from drop-on-drop impact. Numerical simulations quantitatively reproduce the rebound scenarios and enable quantification of velocity profiles, energy transfer, and viscous dissipation. Our results illustrate how varying the offset from head-on alignment and the impact velocity results in controllable rebound dynamics for oil drop collisions on superamphiphobic surfaces.

Bayesian inference of constitutive parameters from video data of the impact dynamics of a ball

2020 ◽  
Vol 90 (8) ◽  
pp. 1795-1810
Author(s):  
Fernando S. Buezas ◽  
Nicolás Fochesatto ◽  
Marta B. Rosales ◽  
Walter Tuckart
Keyword(s):  
Bayesian Inference ◽  
Video Data ◽  
Impact Dynamics ◽  
The Impact ◽  
Constitutive Parameters

Impact Dynamics of Single-Layered Graphene Sheets in Multibody Framework Using Nonlocal-Based-ANCF Modeling

2019 ◽  
Vol 19 (09) ◽  
pp. 1950099
Author(s):  
Qingtao Wang ◽  
Yang Zhang ◽  
Qixin Zhu ◽  
Zhaojun Pang
Keyword(s):  
Pair Potential ◽  
Gold Atom ◽  
Nonlocal Elasticity Theory ◽  
Nonlocal Theory ◽  
Impact Dynamics ◽  
Graphene Sheets ◽  
Dynamic Simulations ◽  
Definition Of ◽  
Vdw Force ◽  
The Impact

A new nonlinear model based on the absolute nodal coordinate formulation (ANCF) and the nonlocal elasticity theory is proposed to investigate the single-layered graphene sheets (SLGSs) impacted by nanoparticles. The geometrical definition of SLGSs is described by using the ANCF thin plate element, and the strain energy is expressed by using the nonlocal theory. The Lennard–Jones pair potential is adopted to model the van der Waals (vdW) force between SLGSs and nanoparticles. The impact dynamics of the system is simulated in multibody framework by using the generalized-alpha numerical integration method. The impact response of the gold atom–SLGSs system is simulated to validate the performance of the proposed model. Three impact dynamic simulations are conducted to investigate the influence of nanoparticles on the impact dynamics of SLGSs. The results show that the coupling of SLGSs vibration and vdW force led to the amplitude inconsistence of [Formula: see text]-position for nanoparticles.

Nano-Scale Impact Characteristics of Rough Surfaces in Humid Atmosphere With Full or Partial SAM Protection

2008 ◽  
Author(s):  
Mircea Teodorescu ◽  
Stephanos Theodossiades ◽  
Homer Rahnejat
Keyword(s):  
Rough Surfaces ◽  
Negligible Effect ◽  
Impact Dynamics ◽  
Fundamental Physics ◽  
Humid Atmosphere ◽  
Micro Scale ◽  
Nano Scale ◽  
Fundamental Understanding ◽  
Impact Characteristics ◽  
The Impact

The impact dynamics of micro-scale mechanisms deviates from the classical theories applied to traditional macro-systems, This is because of multiplicity of forces acting in nano-scale contacts, which have negligible effect at the larger scale. A fundamental understanding of these forces and their interplay is required to advise design of such mechanisms based on fundamental physics. The paper highlights the significance of some of these forces and circumstances where their influence becomes significant.

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