Integrated Dynamic Thermo-Mechanical Modeling of High Speed Spindles, Part 1: Model Development

2004 ◽  
Vol 126 (1) ◽  
pp. 148-158 ◽  
Author(s):  
Hongqi Li ◽  
Yung C. Shin
Keyword(s):  
Dynamic Model ◽  
Thermal Model ◽  
High Speed ◽  
Model Development ◽  
Beam Theory ◽  
Operating Conditions ◽  
Design Parameters ◽  
Fully Integrated ◽  
Temperature Distributions ◽  
Coupling Procedure

This paper presents a comprehensive integrated thermo-dynamic model for various high speed spindles. The entire model consists of fully coupled three sub-models: bearing, spindle dynamic and thermal models. Using a finite element approach, a new thermal model has been generated, which can describe complex structures of high-speed motorized spindles, and can predict more accurate temperature distributions. The spindle dynamic model is constructed using finite elements based on Timoshenko beam theory and has been improved by considering shear deformation, material and bearing damping, and the spindle/tool-holder interface. Using the new thermo-dynamic model, more general and detailed bearing configurations can be modeled through a systematic coupling procedure. The thermal expansions of the shaft, housing and bearings are calculated based on predicted temperature distributions and are used to update the bearing preloads depending on the operating conditions, which are again used to update the thermal model. Therefore, the model is fully integrated and can provide solutions in terms of all the design parameters and operating conditions.

Fundamental Design Issues of Brush Seals for Industrial Applications

2002 ◽  
Vol 124 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Saim Dinc ◽  
Mehmet Demiroglu ◽  
Norman Turnquist ◽  
Jason Mortzheim ◽  
Gayle Goetze ◽  
...  
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Design Parameters ◽  
Design Criteria ◽  
Seal Design ◽  
Brush Seal ◽  
Brush Seals ◽  
As Stress

Advanced seals have been applied to numerous turbine machines over the last decade to improve the performance and output. Industrial experiences have shown that significant benefits can be attained if the seals are designed and applied properly. On the other hand, penalties can be expected if brush seals are not designed correctly. In recent years, attempts have been made to apply brush seals to more challenging locations with high speed (>400 m/s), high temperature (>650 °C), and discontinuous contact surfaces, such as blade tips in a turbine. Various failure modes of a brush seal can be activated under these conditions. It becomes crucial to understand the physical behavior of a brush seal under the operating conditions, and to be capable of quantifying seal life and performance as functions of both operating parameters and seal design parameters. Design criteria are required for different failure modes such as stress, fatigue, creep, wear, oxidation etc. This paper illustrates some of the most important brush seal design criteria and the trade-off of different design approaches.

An integrated model for high-speed motorized spindles – Dynamic behaviors

2013 ◽  
Vol 227 (11) ◽  
pp. 2467-2478 ◽  
Author(s):  
Xiao-an Chen ◽  
Jun-feng Liu ◽  
Ye He ◽  
Peng Zhang ◽  
Wen-tao Shan
Keyword(s):  
Dynamic Model ◽  
Heat Generation ◽  
Thermal Model ◽  
High Speed ◽  
High Efficiency ◽  
Solution Procedure ◽  
Integrated Model ◽  
Dynamic Behaviors ◽  
Dynamic Performances ◽  
Motorized Spindles

With increasing popularity in high-speed machining due to its high efficiency, there is a vital need for more accurate prediction of dynamic behaviors for high-speed motorized spindles. The spindle units integrate tools with built-in motors hence a comprehensive model is required to include the multi-physics coupling property. This article presents an integrated model which consists of four coupled sub-models: state, shaft, bearing, and thermal model. Using the variational principle, a state model for the motor-spindle system is generated, which can describe the running state of the spindle, and provide electrical parameters to study the motor heat generation for thermal model and the unbalanced magnetic force for shaft dynamic model. The thermal model is coupled with the bearing and shaft dynamic model through bearing heat generation and thermal displacement. Thus, the entire model becomes an integrated electro-thermo-mechanical dynamic model. The proposed integrated model is investigated by a solution procedure and validated experimentally, and it shows that the model is capable of accurately predicting the dynamic behaviors of motorized spindles. The coupling relationship among the electrical, thermal, and mechanical behaviors of the system becomes clear from the simulation and experimental results, and some feasible methods to improve the dynamic performances of the system are obtained.

scholarly journals A rupture limit equation for COPVs following a perforating MMOD impact

2019 ◽  
Author(s):  
William P. Schonberg
Keyword(s):  
Pressure Vessel ◽  
High Speed ◽  
Pressure Vessels ◽  
Hypervelocity Impact ◽  
Operating Conditions ◽  
Design Parameters ◽  
Particle Impact ◽  
Catastrophic Failure ◽  
Limit Equation ◽  
Loss Of Life

Abstract Most spacecraft have at least one pressurized vessel on board. One of the primary design considerations for earth-orbiting spacecraft is the anticipation and mitigation of the possible damage that might occur in the event of a micrometeoroid or orbital debris (MMOD) particle impact. To prevent mission failure and possibly loss of life, protection against perforation by such high-speed impacts must be included. In addition to a hole, it is possible that, for certain pressure vessel designs, materials, impact parameters, and operating conditions, a pressure vessel may experience catastrophic failure (i.e. rupture) as a result of a hypervelocity impact. If such a tank rupture were to occur on-orbit following an MMOD impact, not only could it lead to loss of spacecraft, but quite possibly, for human missions, it could also result in loss of life. In this paper we present an update to a Rupture Limit Equation, or RLE, for composite overwrapped pressure vessels (COPVs) that was presented previously. The update consists of modified RLE parameters and coefficients that were obtained after the RLE was re-derived using new / additional data. The updated RLE functions in a manner similar to that of a ballistic limit equation, or BLE, that is, it differentiates between regions of operating and impact conditions that, given a tank wall perforation, would result in either tank rupture or only a relatively small hole or crack. This is an important consideration in the design of a COPV pressurized tank – if possible, design parameters and operating conditions should be chosen such that additional sizable debris (such as that which would be created in the event of tank rupture or catastrophic failure) is not created as a result of an on-orbit MMOD particle impact.

Jumping Phenomenon in Journal Bearing

1991 ◽  
Author(s):  
Krystof Kryniski
Keyword(s):  
High Speed ◽  
Standard Procedure ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Theory And Practice ◽  
Fluid Film ◽  
Design Parameters ◽  
Radial Clearance ◽  
Rotor Systems ◽  
Rotating Machine

Abstract Due to their reliability and low maintenance costs over an extended service time, the journal bearings, also known as fluid-film bearings, are commonly incorporated in the super-critical rotor systems. Together with proven balancing methods, they allow rotating machine to pass smoothly through the various of critical speeds, both during start-ups and shut-downs. However, journal bearings need to be designed very carefully, as at some operating conditions (speed and load), they may introduce the undesired effects, such as unstable operations or sub-harmonic resonances. The standard procedure leading to the optimum fluid-film bearing design is based on the bearing capacity, defined by the Sommerfield number [1][2]. When Sommerfield number is determined, all design parameters, such as viscosity, radial clearance, diameter and rotation speed, etc. are matched to satisfy the engineering requirements specified. The procedure is considered to be completely reliable and is commonly used in turbo-machinery and high-speed compressor design. However, the significant divergences between theory and practice were observed with the increase of a bearing radial clearance [3].

scholarly journals Transient Temperature Distributions on Lithium-Ion Polymer SLI Battery

Vehicles ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Yiqun Liu ◽  
Y. Gene Liao ◽  
Ming-Chia Lai
Keyword(s):  
Thermal Management ◽  
Thermal Model ◽  
Operating Temperature ◽  
Lithium Ion ◽  
Operating Conditions ◽  
Battery Pack ◽  
Transient Temperature ◽  
Temperature Distributions ◽  
Lithium Ion Polymer Battery ◽  
Polymer Battery

Lithium-ion polymer batteries currently are the most popular vehicle onboard electric energy storage systems ranging from the 12 V/24 V starting, lighting, and ignition (SLI) battery to the high-voltage traction battery pack in hybrid and electric vehicles. The operating temperature has a significant impact on the performance, safety, and cycle lifetime of lithium-ion batteries. It is essential to quantify the heat generation and temperature distribution of a battery cell, module, and pack during different operating conditions. In this paper, the transient temperature distributions across a battery module consisting of four series-connected lithium-ion polymer battery cells are measured under various charging and discharging currents. A battery thermal model, correlated with the experimental data, is built in the module-level in the ANSYS/Fluent platform. This validated module thermal model is then extended to a pack thermal model which contains four parallel-connected modules. The temperature distributions on the battery pack model are simulated under 40 A, 60 A, and 80 A constant discharge currents. An air-cool thermal management system is integrated with the battery pack model to ensure the operating temperature and temperature gradient within the optimal range. This paper could provide thermal management design guideline for the lithium-ion polymer battery pack.

Effect of structural design parameters on nonlinear dynamic characteristics of the gear transmission

2021 ◽  
pp. 095440702110294
Author(s):  
Tiancheng Ouyang ◽  
Rui Yang ◽  
Yudong Shen ◽  
Jingxian Chen ◽  
Nan Chen
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Gear Tooth ◽  
Spur Gear ◽  
Operating Conditions ◽  
Design Parameters ◽  
Meshing Stiffness ◽  
Nonlinear Dynamic Characteristics ◽  
Potential Energy Method

The calculation of time-varying meshing stiffness caused by the alternate contacting of the gear tooth is an essential prerequisite to obtain real and effective nonlinear dynamic characteristics of the transmission system, so that the significance of which cannot be overemphasized. Accordingly, this work proposes an improved method to get meshing stiffness with taking fillet-foundation and gear rim deflection into consideration. Compared to the traditional potential energy method, the proposed method has more superior accuracy and performance, and its effectiveness has been further verified by the finite element analytical model. After that, an ideal eight degree of freedoms (DOFs) dynamic model of one stage mass-spring-damper involute spur gear, including lateral and torsional motions, is established to study the dynamic characteristics. Due to the complexity of the gear system operating conditions, we also investigate the influence of various parameters including hub bore radius, transmitting load, and rotation speed on dynamic features, especially in heavy-load and high-speed conditions. From the results, it can be concluded that these parameters will play a prominent role in the spur gear pair dynamic behaviors, providing a certain guidance for gear design.

scholarly journals Investigation of the thermal effect of a tubular permanent magnet actuator with a water cooling channel for active lateral suspension of a high-speed train

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401881966
Author(s):  
Dong-wook Kim ◽  
Jung-Hyun Woo ◽  
Kyoung-Su Park
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Ride Comfort ◽  
Cooling System ◽  
Operating Conditions ◽  
Design Parameters ◽  
Water Cooling ◽  
Transfer Coefficients ◽  
Permanent Magnet Actuator ◽  
Water Cooling System

Worldwide, high-speed rail is becoming an increasingly popular and efficient means of transport. However, increasing the speed of a train leads to major reductions in stability and ride comfort. Here, we develop a tubular permanent magnet actuator to overcome these problems. To increase actuator thrust, the electromagnetic circuit requires a high current and, thus, becomes hot. We use a water cooling system with 12 straight copper channels to reduce the temperature. We calculate heat transfer coefficients using empirical convection correlations between laminar flow in the channels and experimental results. The predicted, tube surface temperatures correlated well with the experimental data. We evaluated the effects of flow rate and initial water temperature on various design parameters. The cooling system allowed application of a current greater than 100 A, developing a thrust force of over 8000 N. Thus, the system was robust under harsh operating conditions. We measured the thrust and cogging forces and the performance of the water cooling system in terms of the maximum acceptable temperature. The thrust was high and the cogging torque was low, greatly reducing lateral vibration; the temperature remained below the acceptable maximum.

Traction behaviours of aviation lubricating oil and the effects on the dynamic and thermal characteristics of high-speed ball bearings

2019 ◽  
Vol 72 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Zhen Li ◽  
Yufan Lu ◽  
Chi Zhang ◽  
Jinlong Dong ◽  
Xiaoli Zhao ◽  
...  
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Least Squares Method ◽  
Traction Force ◽  
Operating Conditions ◽  
Lubricating Oil ◽  
Ball Bearings ◽  
Content Type ◽  
Rapid Calculation ◽  
Synthetic Aviation

Purpose The traction behaviours of lubricating oil significantly affect the stability and lubrication regime of aviation high-speed ball bearings. Rolling elements will slide at a low traction force (TF). Therefore, traction behaviours need to be studied, and a fitting expression for traction curves to rapidly calculate the traction coefficient (TC) should be developed. Design/methodology/approach The traction behaviours of an aviation lubricating oil were studied in severe operating conditions with a self-designed two-disc testing rig. Based on the least squares method and the Levenberg–Marquardt theory, a rapid calculation expression was developed by fitting the obtained traction curves. The correction of this expression was experimentally verified by comparing the TCs under different operating conditions. This expression was also used to modify the commonly accepted quasi-dynamic model of rolling bearings. Findings An increase of the load led to an increase in the TC. In comparison, the temperature and entrainment speed showed inverse effects. The proposed expression exactly predicted the trend of the experimentally acquired traction curve. The calculation with the modified dynamic model showed that the action of the TF on a single rolling element varied and that the temperature increase of the outer raceway is higher than the inner raceway, which is caused by the TF and relative sliding speed between the elements and raceways. Originality/value The proposed fitting expression is able to simplify the TC calculation of synthetic aviation lubricating oil in practical engineering applications. This paper can provide an important reference for the traction behaviour of synthetic aviation lubricating oil under severe conditions and assist with its rapid calculation and practical application in engineering.

ELECTRO-RHEOLOGICAL CATCH/CLUTCH: INERTIAL SIMULATIONS

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2935-2954
Author(s):  
A. R. JOHNSON ◽  
J. MAKIN ◽  
W. A. BULLOUGH
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Integrated Approach ◽  
High Yield ◽  
High Shear ◽  
Fully Integrated ◽  
Shear Rates ◽  
High Shear Rates ◽  
General Investigation ◽  
Machinery Design

A high-speed reciprocating mechanism is described in order to provide the basis of a general investigation into the required properties of electro-rheological fluids and associated materials for use in flexible, inertial mechanisms. The dynamic model of this, when run for realistic existing machine requirements clearly illustrates the need for a fully integrated approach to high speed machinery design. The work sets quantified targets and draws attention to the need for the continuing development of improved electro-rheological fluids which will have high yield stresses with acceptable viscosities and the conditions they must operate under: high shear rates, centrifugal loadings and accelerations.

Bearings Influence on the Dynamic Behavior of HSM Spindle

2012 ◽  
Author(s):  
David Noel ◽  
Mathieu Ritou ◽  
Sebastien Le Loch ◽  
Benoit Furet
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Design Parameters ◽  
Mechanics Model ◽  
Bearing Stiffness ◽  
Rough Milling ◽  
The Impact

The aeronautic industry requires high speed and high power spindles to obtain high material removal rates during long rough milling operations. The weakness of HSM spindle is the bearings, although high precision hybrid ball bearings have been developed to achieve this critical application. Inadequate use of spindles inevitably leads to shortened lifetimes. Choosing the operating conditions is a required step before machining applications. It can be achieved through either experimental tests or numerical modeling that leads to stability lobe diagrams. Stability of cuts relies on the dynamic behavior of the spindle, which is particularly due to the eigenfrequencies of the tool-shaft assembly. The frequencies depend on bearing stiffness that can change under operating conditions. That is why the impact of cutting conditions and bearing parameters on its stiffness are studied in the paper. A five degrees of freedom model of angular ball bearing is briefly presented. A complete bearing model is introduced. The originality of the approach is the complete technological modeling, notably of the radial expansions of inner and outer rings of bearing. A non-linear expression is established from continuum mechanics model. The influence of geometry of bearing, operating conditions and design parameters of spindle on the bearing stiffness are established and analysed. Then, modal analyses of the tool-spindle assembly are carried out in relation to the varying bearing stiffness. Finally, significance of the approach is demonstrated through the analyses of Frequency Response Function.

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