Effects of Transient Powertrain Shift Dynamics on Vehicle Handling

2004 ◽  
Author(s):  
Taehyun Shim ◽  
Yi Zhang
Keyword(s):  
Model Simulation ◽  
Automatic Transmission ◽  
Transient Behavior ◽  
Drive Shaft ◽  
Lumped Mass ◽  
Mass Model ◽  
Vehicle Handling ◽  
Shaft Torque ◽  
Shift Dynamics ◽  
Suspension Model

This paper investigates the effect of drive shaft torque variations during transmission shifts on vehicle handling performance. In this paper, a lumped mass model for a 4-speed automatic transmission powertrain and a 14-degree-of-freedom vehicle models have been developed and used jointly for the simulation of vehicle transient behavior during the shift processes. In the investigation, the powertrain model is used as the pre-processor to obtain realistic drive shaft torque that reflects the torque variations intrinsic of transmission shifts. The drive shaft torque thus obtained then serves as the input for the vehicle suspension model. This approach provides better accuracy for vehicle handling analysis than the existing approach that assumes a steady state axle torque. A mid-size sedan was used as an example in the investigation. Based on model simulation, vehicle responses to powertrain shift transients under various road conditions were quantitatively analyzed and compared with that obtained by the existing method.

A Comparison of Inverse Models for the Estimation of Ice-Induced Propeller Moments on a Polar Vessel

2021 ◽  
Author(s):  
Brendon M. Nickerson ◽  
Anriëtte Bekker
Keyword(s):  
Rotational Speed ◽  
Continuous Model ◽  
Full Scale ◽  
Lumped Mass ◽  
Mass Model ◽  
Inverse Models ◽  
Lumped Mass Model ◽  
Ill Posed ◽  
Shaft Torque ◽  
Measurement Location

Abstract Full-scale measurements were conducted on the port side propulsion shaft the S.A. Agulhas II during the 2019 SCALE Spring Cruise. The measurements included the shaft torque captured at two separate measurement locations, and the shaft rotational speed at one measurement location. The ice-induced propeller moments are estimated from the full-scale shaft responses using two inverse models. The first is a published discrete lumped mass model that relies on regularization due to the inverse problem being ill-posed. This model is only able to make use of the propulsion shaft torque as inputs. The second model is new and employs modal superposition to represent the propulsion shaft as a combination of continuous modes, resulting in a well-posed problem. This new model requires the additional measurement of the shaft rotational speed for the inverse solution. The continuous model is shown to be more consistent and efficient, which allows its use in real-time monitoring of propeller moments.

The Bending Vibration Analysis on the Main Drive Axis of CNC Spiral Bevel Gear Milling Machine

2013 ◽  
Vol 655-657 ◽  
pp. 1296-1299
Author(s):  
Li Juan Yu ◽  
Zhao Jun Yang ◽  
Fu You Liu
Keyword(s):  
Drive Shaft ◽  
Resonance Problem ◽  
Parameter Method ◽  
Force Model ◽  
Lumped Mass ◽  
Mass Model ◽  
Bending Vibration ◽  
Lumped Parameter ◽  
Lumped Mass Model ◽  
Lumped Parameter Method

Gear machine tool main drive shaft to avoid resonance problem is studied.The force of the drive shaft is analyzed, and the vibration form of the drive shaft is confirmed. Using the lumped parameter method to simplify the main drive shaft, the lumped mass model and the force model were been obtained. When bending vibrating, the natural frequency of the main drive shaft is calculated using the transfer matrix method. The calculated critical speed is 43755r/min, which far outweighs the motor rated speed .It means that the drive shaft under normal work won't be resonance, which accords with the request of production.

The Drive Axis Simulate Analysis on the Spiral Bevel Gear Milling Machine

2013 ◽  
Vol 365-366 ◽  
pp. 281-284
Author(s):  
Li Juan Yu ◽  
Xu Peng Li ◽  
Fu You Liu ◽  
Fei Zheng
Keyword(s):  
Bevel Gear ◽  
Drive Shaft ◽  
Parameter Method ◽  
Spiral Bevel Gear ◽  
Force Model ◽  
Milling Machine ◽  
Feed System ◽  
Lumped Mass ◽  
Mass Model ◽  
Spiral Bevel

The tool feed system main drive shaft of CNC spiral bevel gear milling machine is researched, and the vibration form of the drive shaft is confirmed.The main drive shaft is simplified using the lumped parameter method, the lumped mass model and the force model were been obtained. When bending vibrating, the natural frequency of the main drive shaft is calculated using the transfer matrix method. In order to verify the correctness of the calculations, the vibration of the main drive shaft is simulated by using ANSYS. This paper also designs the vibration control system for the main drive shaft, and analyzes influence factors which affects the vibration of the main drive shaft.

On Uncertainty Assessment of Fatigue Damage of Propulsion Shaft Under Ice Impact

2021 ◽  
Author(s):  
Etienne Purcell ◽  
Amir R. Nejad ◽  
Mostafa Valavi ◽  
Anriëtte Bekker
Keyword(s):  
Fatigue Damage ◽  
Model Simulation ◽  
Uncertainty Assessment ◽  
Assessment Method ◽  
Remaining Useful Life ◽  
Lumped Mass ◽  
Short Term ◽  
Mass Model ◽  
Sources Of Uncertainty ◽  
Ice Loads

Abstract In this paper, the importance of maintenance of marine propulsion is discussed with specific focus on the use of condition monitoring to inform maintenance schedules. The design requirements of DNV GL for shafts expected to operate in ice infested waters is adapted and a method is proposed to calculate the short-term fatigue damage during ice impacts. This method uses the Palmgren-Miner rule to calculate fatigue damage based on a transient, lumped-mass model simulation of the shaft with ice loads calculated from shaft measurements using inverse methods. Relevant sources of uncertainty in this assessment method are identified and quantified in order to express the short-term fatigue damage in a stochastic form. Sources of uncertainty include uncertainty in the calculation of ice loads, uncertainty of the transient analysis and uncertainty regarding the actual failure of the shaft as predicted by the S-N material curve and the Palmgren-Miner method. Uncertainties that influence the stress history are found to be the greatest contributor to fatigue damage uncertainty. A method is discussed that calculates the remaining useful life of the shaft as a function of short-term fatigue damage and the identified sources of uncertainty. The S.A. Agulhas is used as a case study to quantify the fatigue damage.

A comparison of different models of passive seat suspensions

2021 ◽  
pp. 095440702199092
Author(s):  
Raj Desai ◽  
Anirban Guha ◽  
P. Seshu
Keyword(s):  
Human Body ◽  
Separate Analysis ◽  
Vehicle Model ◽  
Human Body Model ◽  
Human Comfort ◽  
Vehicle Handling ◽  
Seat Suspension ◽  
Handling Characteristics ◽  
Suspension Model ◽  
Suspension Models

Long duration exposure to vehicle induced vibration causes various ailments to humans. Amongst the various components of the human-vehicle system, the seat suspension plays a major role in determining the level of vibration transferred to humans. However, optimising the suspension for maximising human comfort leads to poor vehicle handling characteristics. Thus, predicting human comfort through various seat suspension models is a widely researched topic. However, the appropriate seat suspension model to be used has not been identified so far. Neither has any prior work reported integrating models of all the components necessary for this analysis, namely human body, cushion, seat suspension and vehicle chassis, each with the appropriate level of complexity. This work uses a two-dimensional 12 DoF seated human body model with inclined backrest support, a nonlinear cushion model, a seat suspension model and a full vehicle model. Two kinds of road profiles – one with random roughness and one with a bump – have been used. It then compares the performance of five different seat suspension models based on a number of human comfort related parameters (seat to head transmissibility, suspension travel, seat acceleration, cushion contact force and head acceleration in both vertical and fore-aft directions) and vehicle handling parameters (vertical, rolling and pitching acceleration of chassis). The results clearly show the superiority of the configuration which involves a spring parallel to an inclined multi-stage damper. A separate analysis was also done to judge whether the integration of the vehicle model (with its associated complication) was necessary for this analysis. A comparison of the human body’s internal forces, moments, acceleration, and absorbed power with and without the vehicle model clearly indicates the need of using the former.

Analysis of Mistuned Blade Vibrations Based on Normally Distributed Blade Individual Natural Frequencies

2015 ◽  
Author(s):  
Felix Figaschewsky ◽  
Arnold Kühhorn
Keyword(s):  
Probability Distribution ◽  
Development Process ◽  
Structural Model ◽  
Natural Frequencies ◽  
Rotor Blades ◽  
Lumped Mass ◽  
Mass Model ◽  
Influence Coefficients ◽  
Random Mistuning ◽  
Rotor Assembly

With increasing demands for reliability of modern turbomachinery blades the quantification of uncertainty and its impact on the designed product has become an important part of the development process. This paper aims to contribute to an improved approximation of expected vibration amplitudes of a mistuned rotor assembly under certain assumptions on the probability distribution of the blade’s natural frequencies. A previously widely used lumped mass model is employed to represent the vibrational behavior of a cyclic symmetric structure. Aerodynamic coupling of the blades is considered based on the concept of influence coefficients leading to individual damping of the traveling wave modes. The natural frequencies of individual rotor blades are assumed to be normal distributed and the required variance could be estimated due to experiences with the applied manufacturing process. Under these conditions it is possible to derive the probability distribution of the off-diagonal terms in the mistuned equations of motions, that are responsible for the coupling of different circumferential modes. Knowing these distributions recent limits on the maximum attainable mistuned vibration amplitude are improved. The improvement is achieved due to the fact, that the maximum amplification depends on the mistuning strength. This improved limit can be used in the development process, as it could partly replace probabilistic studies with surrogate models of reduced order. The obtained results are verified with numerical simulations of the underlying structural model with random mistuning patterns based on a normal distribution of individual blade frequencies.

Experimental and Numerical Modal Analysis of Composite Laminated Shells

2019 ◽  
Vol 161 (A1) ◽  
Keyword(s):  
Heat Dissipation ◽  
Mass Matrix ◽  
Experimental Studies ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Radius Of Curvature ◽  
Lumped Mass ◽  
Auxiliary Equipment ◽  
Mass Model ◽  
Laminated Shells

The presence of cut outs at different positions of laminated shell component in marine and aeronautical structures facilitate heat dissipation, undertaking maintenance, fitting auxiliary equipment, access ports for mechanical and electrical systems, damage inspection and also influences the dynamic behaviour of the structures. The aim of the present study is to establish a comprehensive perspective of dynamic behavior of laminated deep shells (length to radius of curvature ratio less than one) with cut-out by experiments and numerical simulation. The glass epoxy laminated composite shell has been prepared in the laboratory by resin infusion. The experimental free vibration analysis is carried out on laminated shells with and without cut-out. The mass matrix is developed by considering rotary inertia in a lumped mass model in the numerical modeling. The results obtained from numerical and experimental studies are compared for verification and the consistency between mode shapes is established by applying modal assurance criteria.

Modeling and Analysis of an Optically-Actuated, Bistable MEMS Device

2010 ◽  
Author(s):  
Vijay Kumar ◽  
Jeffrey F. Rhoads
Keyword(s):  
Transient Behavior ◽  
Distributed Parameter ◽  
Mems Devices ◽  
Lumped Mass ◽  
Modeling And Analysis ◽  
Mems Switch ◽  
The Rich ◽  
Predictive Design ◽  
Commercial Applications ◽  
Excitation Parameters

Bistable microsystems have drawn considerable interest from the MEMS/NEMS research community not only due to their broad applicability in commercial applications, such as switching, but also because of the rich dynamic behavior they commonly exhibit. While a number of prior investigations have studied the dynamics of bistable microsystems, comparatively few works have sought to characterize their transient behavior. The present effort seeks to address this through the modeling and analysis of an optically-actuated, bistable MEMS switch. The work begins with the development of a distributed-parameter representation for the system, which is subsequently reduced to a lumped-mass analog and analyzed through the use of numerical simulation. The influence of various system and excitation parameters, including the applied axial load and optical actuation profile, on the system’s transient response is then investigated. Ultimately, the methodologies and results presented herein should provide for a refined predictive design capability for optically-actuated, bistable MEMS devices.

Coupled Torsional Vibration and Fatigue Damage of Turbine Generator Due to Grid Disturbance

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Chao Liu ◽  
Dongxiang Jiang ◽  
Jingming Chen
Keyword(s):  
Fatigue Damage ◽  
Torsional Vibration ◽  
Coupled System ◽  
Lumped Mass ◽  
Mass Model ◽  
Turbine Generator ◽  
Failure Prevention ◽  
Lumped Mass Model ◽  
Continuous Mass ◽  
Fatigue Evaluation

Crack failures continually occur in shafts of turbine generator, where grid disturbance is an important cause. To estimate influences of grid disturbance, coupled torsional vibration and fatigue damage of turbine generator shafts are analyzed in this work, with a case study in a 600MW steam unit in China. The analysis is the following: (i) coupled system is established with generator model and finite element method (FEM)-based shafts model, where the grid disturbance is signified by fluctuation of generator outputs and the shafts model is formed with lumped mass model (LMM) and continuous mass model (CMM), respectively; (ii) fatigue damage is evaluated in the weak location of the shafts through local torque response computation, stress calculation, and fatigue accumulation; and (iii) failure-prevention approach is formed by solving the inverse problem in fatigue evaluation. The results indicate that the proposed scheme with continuous mass model can acquire more detailed and accurate local responses throughout the shafts compared with the scheme without coupled effects or the scheme using lumped mass model. Using the coupled torsional vibration scheme, fatigue damage caused by grid disturbance is evaluated and failure prevention rule is formed.

scholarly journals Smooth Gear Shift Control System of Automatic Transmission Using Estimated Output Shaft Torque.

1995 ◽  
Vol 61 (591) ◽  
pp. 4334-4338
Author(s):  
Toshimichi Minowa ◽  
Hiroshi Kimura ◽  
Junichi Ishii ◽  
Masahiko Ibamoto
Keyword(s):  
Control System ◽  
Automatic Transmission ◽  
Output Shaft ◽  
Gear Shift ◽  
Shift Control ◽  
Shaft Torque
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