Study of Transient Response of a Gear Train Under Pulsating Torque

2000 ◽  
Author(s):  
Q. John Zhang ◽  
Jerry Rescigno
Keyword(s):  
Transient Response ◽  
Impact Load ◽  
Model Simulation ◽  
Angular Acceleration ◽  
Nonlinear Behavior ◽  
Power Input ◽  
Gear Train ◽  
Experimental Result ◽  
Reduction Gear ◽  
The Impact

Abstract This paper studied the transient response of a single reduction gear train under a pulsating torque. A 4-DOF model has been used to estimate the impact load on the gear teeth. The system equations are solved under different gear backlash, inertia, stiffness and gear ratio conditions. The sensitivities of impact load versus these parameters have been summarized. The nonlinear behavior of the impact force changing from period to random due to the torque drop is investigated. Angular velocity test verified the power input curve. Angular acceleration and lock-rotor tests show the agreement between the model simulation and experimental result.

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

2019 ◽  
Vol 233 (14) ◽  
pp. 5164-5176 ◽  
Author(s):  
Nanfei Wang ◽  
Chao Liu ◽  
Dongxiang Jiang
Keyword(s):  
Transient Response ◽  
Rotor Blade ◽  
Vibration Amplitude ◽  
Impact Load ◽  
Transient Vibration ◽  
Vibration Displacement ◽  
Highly Nonlinear ◽  
Aero Engine ◽  
Fan Blade ◽  
The Impact

Fan blade off occurring in a running rotor of the turbofan engine dual-rotor system will cause a sudden unbalance and inertia asymmetry, which results in large impact load and consequently induces the rubbing between blade and casing. In order to reveal the transient dynamic response characteristics of actual aero-engine when fan blade off event occurs, the dynamic model of dual-rotor-blade-casing system is developed, in which the distribution characteristics of the stiffness and mass, the load transfer, and the coupling effects of dual-rotor and casing are included. Considering several excitations caused by blade off, the physical process and mechanical characteristics of the fan blade off event are described qualitatively. Considering that only the casing acceleration signal can be used for condition monitoring in actual aero-engine, the transient response including rotor vibration displacement and casing vibration acceleration during the instantaneous status are obtained. Due to the time-varying and highly nonlinear characteristics of vibration responses, frequency slice wavelet transform is employed to isolate the vibration signal features. The results show that the impact load induced by the sudden imbalance causes significant increase of vibration amplitude. The rubbing action between blade and rotor will impose constraint effects on the rotor, which decreases the transient vibration amplitude. The inertia asymmetry has a big impact on the transient response. The vibration characteristics of casing acceleration under blade off are similar to those of rotor displacement, while casing acceleration response attenuates to stable value faster and is more sensitive to high-frequency components of vibration.

THE EFFECT OF SHEAR REINFORCEMENT RATIO ON PRESTRESSED CONCRETE BEAMS SUBJECTED TO IMPACT LOAD

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohamad Elani ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Youmn Al Rawi
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Impact Load ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Shear Reinforcement ◽  
Dynamic Increase Factor ◽  
Concrete Damage ◽  
Different Response ◽  
The Impact

Structural elements subjected to impact loads have a different response than those subjected to static loads. This research studied the effect of using shear reinforcement to reduce the local damage occurred when an impact load applied on a prestressed concrete beam. An accurate finite element model was provided for the analysis using the advanced volumetric finite element modeling program (ABAQUS). The concrete material was defined using the built in concrete damage plasticity model (CDP), that considers the nonlinear behavior of concrete when subjected to dynamic loading. All material properties were modified using the dynamic increase factor (DIF) to consider the effect of impact loading. It was realized that the failure was concentrated in the impact zone. However, using shear reinforcement reduced the permanent damage occurred due to impact.

Study on the Impact Response of Concrete Filled FRP-Steel Tube Structures

2011 ◽  
Vol 368-373 ◽  
pp. 549-552
Author(s):  
Chen Chen ◽  
Ying Hua Zhao ◽  
Chun Yang Zhu ◽  
Li Wei
Keyword(s):  
Impact Load ◽  
Steel Tube ◽  
Fiber Reinforced Polymer ◽  
Experimental Result ◽  
Lateral Impact ◽  
Steel Tubes ◽  
Impact Performance ◽  
Reinforced Polymer ◽  
The Impact ◽  
Frp Sheet

This paper studies the impact performance of concrete filled FRP-steel tube which is a composed structure made by filling concrete into steel tube and wrapping outside with fiber reinforced polymer (FRP) sheet. Numerical simulations have been conducted to study the dynamic response of fixed-pined supported beams of concrete filled FRP-steel tubes. The finite element models of concrete filled FRP-steel tubes are established to analyse its lateral impact dynamic characteristics under different loading situations, with respective kinds of FRP and thicknesses of steel tubes. The impact force and displacement histories were recorded. Comparing to the traditional concrete filled steel tube structure, the concrete filled FRP-steel tube indicates a promising structure with more advantages in the mechanical and constructional performance. Especially with its higher loading-carrying capacity and better toughness, it is more adaptable for the structures subjected to accidental impact load. Analytical solution is compared with experimental result to show the correctness and the effectiveness of present study.

scholarly journals Research of Impact Load in Large Electrohydraulic Load Simulator

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongguang Liu ◽  
Xiaohui Gao ◽  
Zhongcai Pei
Keyword(s):  
Impact Load ◽  
Experimental Result ◽  
Actual System ◽  
Good Experimental Condition ◽  
Load Simulator ◽  
Electric Cylinder ◽  
Hardware In Loop ◽  
Hardware In Loop Simulation ◽  
The Impact ◽  
The Mathematical Model

The stronger impact load will appear in the initial phase when the large electric cylinder is tested in the hardware-in-loop simulation. In this paper, the mathematical model is built based on AMESim, and then the reason of the impact load is investigated through analyzing the changing tendency of parameters in the simulation results. The inhibition methods of impact load are presented according to the structural invariability principle and applied to the actual system. The final experimental result indicates that the impact load is inhibited, which provides a good experimental condition for the electric cylinder and promotes the study of large load simulator.

scholarly journals Application of computer agent modeling for optimization of the assembly process

2020 ◽  
pp. 18-25
Author(s):  
І.О. Ушакова
Keyword(s):  
Simulation Model ◽  
Computer Modeling ◽  
Model Simulation ◽  
Optimal Number ◽  
Experimental Result ◽  
Computer Simulation Model ◽  
Assembly Process ◽  
Systems Simulation ◽  
The Impact ◽  
Machine Assembly

Computer modeling is a method for solving the problems of analysis or synthesis of a complex system based on the use of its computer model. Simulation, as a component of computer modeling, allows you to construct most of the possible states of the analyzed system. In this way it allows to correct the processes of assembling machines in a minimum time and with minimal costs, to foresee possible risks and to avoid unreasonable decisions regarding the organization of processes, to reduce material costs. Simulation gives the best results for modeling uncertain or probabilistic systems. Simulation, as a component of computer modeling, gives the best results for modeling systems with uncertainty or with a probabilistic nature. Mathematically calculating all possible variants of the system’s behavior is a laborious task, and using average values in the calculations gives inaccurate results. For assembly production systems, simulation modeling is used to select the optimal production organization parameters. The aim of this work is to build a computer simulation model that allows you to evaluate the impact of production factors (number of employees, operating parameters and type of assembly process) on the assembly process and substantiate the effectiveness of the model. The current assembly process of the machine was considered for modeling. The assembly process includes: two streams of verification, synchronization of request from these two streams, and a machine collection stream. The vacated line starts servicing the application that entered the system earlier than others. Such a discipline is called “earlier entered - earlier served” (FIFO - First In - First Out).s from flows, and a machine assembly flow. An optimization experiment was carried out after the construction and verification of the simulation model. The maximum value of profit was chosen as the objective function. Iterations were performed during an optimization experiment. The optimal number of employees was selected for two inspection flows and a machine assembly stream in the assembly shop. The first experimental result showed the effectiveness of the request flow synchronization method. The following optimization experiment showed the relationship between the number of workers in certain threads of the assembly process and profit. The results of using agent-based models for simulation can be used to optimize assembly processes.

scholarly journals Experiment and Analysis on the Free Dynamics of a Shallow Arch After an Impact Load at the End

2005 ◽  
Vol 72 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Jen-San Chen ◽  
Chun-Yi Liao
Keyword(s):  
Transient Response ◽  
Impact Load ◽  
Minimum Energy ◽  
The Other ◽  
Initial Speed ◽  
Attached Mass ◽  
Shallow Arch ◽  
Theoretical Predictions ◽  
The Impact ◽  
Good Agreement

In this paper we consider a sinusoidal arch with one end pinned in space while the other end attached to a mass and supported by a spring. The supporting wall of the spring is moved a distance quasi-statically to initiate preload in the arch and the spring. The assembly is then set in motion by an impact at the attached mass. The condition under which the arch may snap to the other side dynamically depends on the initial speed of the attached mass due to impact. Sufficient condition on the initial speed against dynamic snap-through is formulated based on the concept of minimum energy barrier. The effects of damping on the transient response of the assembly are also discussed. An experimental setup is designed to measure the transient response of the arch following the impact and the critical initial speed of the attached mass. The experimental results are in good agreement with theoretical predictions.

Histology and Trabecular Architecture of the Brain for Modeling of Subarachnoid Space

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
Impact Load ◽  
Angular Acceleration ◽  
Trabecular Architecture ◽  
Solid Materials ◽  
Complex Architecture ◽  
The Impact ◽  
The Brain

Subarachnoid space (SAS) plays an important role in transferring and or damping the impact load or angular acceleration to the brain (Zoghi Sadegh 2009). Previous investigations have over simplified the complex architecture of the trabeculae of SAS and employed soft solid materials. The goal of this study is to investigate the histology, architecture and mechanotransduction of subarachnoid space and in particular the trabeculae. The results of this study facilitate future modeling of the brain and thereby better understanding of the TBI.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

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 Analysis on Force Transmission Characteristics of Two-Legged Shield Support under Impact Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qing-liang Zeng ◽  
Zhao-sheng Meng ◽  
Li-rong Wan ◽  
Cheng-long Wang
Keyword(s):  
Structural Design ◽  
Load Transfer ◽  
Impact Load ◽  
Force Transmission ◽  
Full Account ◽  
Flexible Bodies ◽  
Powered Support ◽  
Structural Design Optimization ◽  
Hinge Points ◽  
The Impact

To study the load transfer characteristics of a two-legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic-elastic deformation characteristics of the support, as a series spring-damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

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