机械专业论文中英文摘要

第一篇：机械专业论文中英文摘要

摘 要

本文主要论述了基于PLC的钢管打捆机控制系统的设计思路和设计过程。主要包括钢管打捆机的汽缸动作的顺序控制和打捆钢带的定长剪切伺服控制以及人机交互界面设计。论文介绍了钢管打捆机的国内外研究情况，说明了研制具有我国自主知识产权的钢管打捆机的必要性，讲述了国家对钢管包装的要求和对钢管打捆机的性能要求；分析了给定结构的钢管打捆机的工作流程和控制要求；设计和选用了钢管打捆机的气动系统和相应的控制系统的硬件；建立了打捆钢带定长剪切伺服控制的数学模型；选用触摸屏进行了人机交互界面的设计；对PLC控制系统的重点和难点程序进行了详细叙述。

本文所设计的钢管打捆机控制系统具有根据设定参数自动对钢管计数、自动剪切打捆钢带、自动完成钢管打捆的动作控制等功能，同时通过触摸屏实现参数的输入和实时显示。

关键词：自动钢管打捆机；定长剪切；变频调速；人机界面

This article mainly discusses the design idea and the design process of the PLC based strapping machine controlling system.It includes the sequence control of the cylinder moves of the strapping machine, the fixed-length shear servo control of the steel packing, and the designs of the Man-machine interface.The thesis introduces the strapping machine’s studying condition both at home and abroad, illustrating the necessity of owning the strapping machine of the Independent intellectual property rights;analyzing the workflow and the control requirements of the given structure strapping machine;designing and choosing the hardware of the strapping machine’s pneumatic system and the corresponded controlling system;establishing the mathematical model of the fixed-length shear servo control;choosing the touch screen to do designs of the Man-machine interface;doing detailed descriptions to the important and difficult process of the PLC controlling system.The strapping machine’s controlling system designed by this thesis owns the functions of counting steels automatically according to the setting

parameters, shearing the packed steels automatically, and fulfilling the motion control of packing steels automatically, and at the same time, realizing the parameters input and the real-time display by the touch screen.Key words: automatic strapping machine;fixed-length shear;frequency control;man-machine interface

第二篇：机械专业论文中英文对照

Gearbox NoiseCorrelation with Transmission Error and Influence of Bearing Preload

ABSTRACT The five appended papers all deal with gearbox noise and vibration.The first paper presents a review of previously published literature on gearbox noise and vibration.The second paper describes a test rig that was specially designed and built for noise testing of gears.Finite element analysis was used to predict the dynamic properties of the test rig, and experimental modal analysis of the gearbox housing was used to verify the theoretical predictions of natural frequencies.In the third paper, the influence of gear finishing method and gear deviations on gearbox noise is investigated in what is primarily an experimental study.Eleven test gear pairs were manufactured using three different finishing methods.Transmission error, which is considered to be an important excitation mechanism for gear noise, was measured as well as predicted.The test rig was used to measure gearbox noise and vibration for the different test gear pairs.The measured noise and vibration levels were compared with the predicted and measured transmission error.Most of the experimental results can be interpreted in terms of measured and predicted transmission error.However, it does not seem possible to identify one single parameter,such as measured peak-to-peak transmission error, that can be directly related to measured noise and vibration.The measurements also show that disassembly and reassembly of the gearbox with the same gear pair can change the levels of measured noise and vibration considerably.This finding indicates that other factors besides the gears affect gear noise.In the fourth paper, the influence of bearing endplay or preload on gearbox noise and vibration is investigated.Vibration measurements were carried out at torque levels of 140 Nm and 400Nm, with 0.15 mm and 0 mm bearing endplay, and with 0.15 mm bearing preload.The results show that the bearing endplay and preload

influence the gearbox vibrations.With preloaded bearings, the vibrations increase at speeds over 2000 rpm and decrease at speeds below 2000 rpm, compared with bearings with endplay.Finite element simulations show the same tendencies as the measurements.The fifth paper describes how gearbox noise is reduced by optimizing the gear geometry for decreased transmission error.Robustness with respect to gear deviations and varying torque is considered in order to find a gear geometry giving low noise in an appropriate torque range despite deviations from the nominal geometry due to manufacturing tolerances.Static and dynamic transmission error, noise, and housing vibrations were measured.The correlation between dynamic transmission error, housing vibrations and noise was investigated in speed sweeps from 500 to 2500 rpm at constant torque.No correlation was found between dynamic transmission error and noise.Static loaded transmission error seems to be correlated with the ability of the gear pair to excite vibration in the gearbox dynamic system.Keywords: gear, gearbox, noise, vibration, transmission error, bearing preload.ACKNOWLEDGEMENTS This work was carried out at Volvo Construction Equipment in Eskilstuna and at the Department of Machine Design at the Royal Institute of Technology(KTH)in Stockholm.The work was initiated by Professor Jack Samuelsson(Volvo and KTH), Professor Sören Andersson(KTH), and Dr.Lars Bråthe(Volvo).The financial support of the Swedish Foundation for Strategic Research and the Swedish Agency for Innovation Systems – VINNOVA – is gratefully acknowledged.Volvo Construction Equipment is acknowledged for giving me the opportunity to devote time to this work.Professor Sören Andersson is gratefully acknowledged for excellent guidance and encouragement.I also wish to express my appreciation to my colleagues at the Department of Machine Design, and especially to Dr.Ulf Sellgren for performing simulations and contributing to the writing of Paper D, and Dr.Stefan Björklund for performing surface finish measurements.The contributions to Paper C by Dr.Mikael

Pärssinen are highly appreciated.All contributionsto this work by colleagues at Volvo are gratefully appreciated.1 INTRODUCTION 1.1 Background Noise is increasingly considered an environmental issue.This belief is reflected in demands for lower noise levels in many areas of society, including the working environment.Employees spend a lot of time in this environment and noise can lead not only to hearing impairment but also to decreased ability to concentrate, resulting in decreased productivity and an increased risk of accidents.Quality, too, has become increasingly important.The quality of a product can be defined as its ability to fulfill customers’ demands.These demands often change over time, and the best competitors in the market will set the standard.Noise concerns are also expressed in relation to construction machinery such as wheel loaders and articulated haulers.The gearbox is sometimes the dominant source of noise in these machines.Even if the gear noise is not the loudest source, its pure high frequency tone is easily distinguished from other noise sources and is often perceived as unpleasant.The noise creates an impression of poor quality.In order not to be heard, gear noise must be at least 15 dB lower than other noise sources, such as engine noise.1.2 Gear noise This dissertation deals with the kind of gearbox noise that is generated by gears under load.This noise is often referred to as “gear whine” and consists mainly of pure tones at high frequencies corresponding to the gear mesh frequency and multiples thereof, which are known as harmonics.A tone with the same frequency as the gear mesh frequency is designated the gear mesh harmonic, a tone with a frequency twice the gear mesh frequency is designated the second harmonic, and so on.The term “gear mesh harmonics” refers to all multiples of the gear mesh frequency.Transmission error(TE)is considered an important excitation mechanism for gear whine.Welbourn [1] defines transmission error as “the difference between

the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate.” Transmission error may be expressed as angular displacement or as linear displacement at the pitch point.Transmission error is caused by deflections, geometric errors, and geometric modifications.In addition to gear whine, other possible noise-generating mechanisms in gearboxes include gear rattle from gears running against each other without load, and noise generated by bearings.In the case of automatic gearboxes, noise can also be generated by internal oil pumps and by clutches.None of these mechanisms are dealt with in this work, and from now on “gear noise” or “gearbox noise” refers to “gear whine”.MackAldener [2] describes the noise generation process from a gearbox as consisting of three parts: excitation, transmission, and radiation.The origin of the noise is the gear mesh, in which vibrations are created(excitation), mainly due to transmission error.The vibrations are transmitted via the gears, shafts, and bearings to the housing(transmission).The housing vibrates, creating pressure variations in the surrounding air that are perceived as noise(radiation).Gear noise can be affected by changing any one of these three mechanisms.This dissertation deals mainly with excitation, but transmission is also discussed in the section of the literature survey concerning dynamic models, and in the modal analysis of the test gearbox in Paper B.Transmission of vibrations is also investigated in Paper D, which deals with the influence of bearing endplay or preload on gearbox noise.Differences in bearing preload influence a bearing’s dynamic properties like stiffness and damping.These properties also affect the vibration of the gearbox housing.1.3 Objective The objective of this dissertation is to contribute to knowledge about gearbox noise.The following specific areas will be the focus of this study: 1.The influence of gear finishing method and gear modifications and errors on noise and vibration from a gearbox.2.The correlation between gear deviations, predicted transmission error, measured transmission error, and gearbox noise.3.The influence of bearing preload on gearbox noise.4.Optimization of gear geometry for low transmission error, taking into consideration robustness with respect to torque and manufacturing tolerances.2 AN INDUSTRIAL APPLICATION − TRANSMISSION NOISE REDUCTION 2.1 Introduction This section briefly describes the activities involved in reducing gear noise from a wheel loader transmission.The aim is to show how the optimization of the gear geometry described in Paper E is used in an industrial application.The author was project manager for the “noise work team” and performed the gear optimization.One of the requirements when developing a new automatic power transmission for a wheel loader was improving the transmission gear noise.The existing power transmission was known to be noisy.When driving at high speed in fourth gear, a high frequency gear-whine could be heard.Thus there were now demands for improved sound quality.The transmission is a typical wheel loader power transmission, consisting of a torque converter, a gearbox with four forward speeds and four reverse speeds, and a dropbox partly integrated with the gearbox.The dropbox is a chain of four gears transferring the powerto the output shaft.The gears are engaged by wet multi-disc clutches actuated by the transmission hydraulic and control system.2.2 Gear noise target for the new transmission Experience has shown that the high frequency gear noise should be at least 15 dB below other noise sources such as the engine in order not to be perceived as disturbing or unpleasant.Measurements showed that if the gear noise could be decreased by 10 dB, this criterion should be satisfied with some margin.Frequency analysis of the noise measured in the driver's cab showed that the dominant noise from the transmission originated from the dropbox gears.The goal for transmission noise was thus formulated as follows: “The gear noise(sound pressure level)from the dropbox

gears in the transmission should be decreased by 10 dB compared to the existing transmission in order not to be perceived as unpleasant.It was assumed that it would be necessary to make changes to both the gears and the transmission housing in order to decrease the gear noise sound pressure level by 10 dB.2.3 Noise and vibration measurements In order to establish a reference for the new transmission, noise and vibration were measured for the existing transmission.The transmission is driven by the same type of diesel engine used in a wheel loader.The engine and transmission are attached to the stand using the same rubber mounts that are used in a wheel loader in order to make the installation as similar as possible to the installation in a wheel loader.The output shaft is braked using an electrical brake.2.4 Optimization of gears Noise-optimized dropbox gears were designed by choosing macro-and microgeometries giving lower transmission error than the original(reference)gears.The gear geometry was chosen to yield a low transmission error for the relevant torque range, while also taking into consideration variations in the microgeometry due to manufacturing tolerances.The optimization of one gear pair is described in more detail in Paper E.Transmission error is considered an important excitation mechanism for gear whine.Welbourn [1] defines it as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate.” In this project the aim was to reduce the maximum predicted transmission error amplitude at gear mesh frequency(first harmonic of gear mesh frequency)to less than 50% of the value for the reference gear pair.The first harmonic of transmission error is the amplitude of the part of the total transmission error that varies with a frequency equal to the gear mesh frequency.A torque range of 100 to 500 Nm was chosen because this is the torque interval in which the gear pair generates noise in its design application.According to Welbourn [1], a 50% reduction in transmission error can be expected to reduce gearbox noise by 6 dB

(sound pressure level, SPL).Transmission error was calculated using the LDP software(Load Distribution Program)developed at the Gear Laboratory at Ohio State University [3].The “optimization” was not strictly mathematical.The design was optimized by calculating the transmission error for different geometries, and then choosing a geometry that seemed to be a good compromise, considering not only the transmission error, but also factors such asstrength, losses, weight, cost, axial forces on bearings, and manufacturing.When choosing microgeometric modifications and tolerances, it is important to take manufacturing options and cost into consideration.The goal was to use the same finishing method for the optimized gears as for the reference gears, namely grinding using a KAPP VAS 531 and CBN-coated grinding wheels.For a specific torque and gear macrogeometry, it is possible to define a gear microgeometry that minimizes transmission error.For example, at no load, if there are no pitch errors and no other geometrical deviations, the shape of the gear teeth should be true involute, without modifications like tip relief or involute crowning.For a specific torque, the geometry of the gear should be designed in such a way that it compensates for the differences in deflection related to stiffness variations in the gear mesh.However, even if it is possible to define the optimal gear microgeometry, it may not be possible to manufacture it, given the limitations of gear machining.Consideration must also be given to how to specify the gear geometry in drawings and how to measure the gear in an inspection machine.In many applications there is also a torque range over which the transmission error should be minimized.Given that manufacturing tolerances are inevitable, and that a demand for smaller tolerances leads to higher manufacturing costs, it is important that gears be robust.In other words, the important characteristics, in this case transmission error, must not vary much when the torque is varied or when the microgeometry of the gear teeth varies due to manufacturing tolerances.LDP [3] was used to calculate the transmission error for the reference and optimized gear pair at different torque levels.The robustness function in LDP was used to analyze the sensitivity to deviations due to manufacturing tolerances.The “min, max, level” method involves assigning three levels to each parameter.2.5 Optimization of transmission housing Finite element analysis was used to optimize the transmission housing.The optimization was not performed in a strictly mathematical way, but was done by calculating the vibration of the housing for different geometries and then choosing a geometry that seemed to be a good compromise.Vibration was not the sole consideration, also weight, cost, available space, and casting were considered.A simplified shell element model was used for the optimization to decrease computational time.This model was checked against a more detailed solid element model of the housing to ensure that the simplification had not changed the dynamic properties too much.Experimental modal analysis was also used to find the natural frequencies of the real transmission housing and to ensure that the model did not deviate too much from the real housing.Gears shafts and bearings were modeled as point masses and beams.The model was excited at the bearing positions by applying forces in the frequency range from 1000 to 3000 Hz.The force amplitude was chosen as 10% of the static load from the gears.This choice could be justified because only relative differences are of interest, not absolute values.The finite element analysis was performed by Torbjörn Johansen at Volvo Technology.The author’s contribution was the evaluation of the results of different housing geometries.A number of measuring points were chosen in areas with high vibration velocities.At each measuring point the vibration response due to the excitation was evaluated as a power spectral density(PSD)graph.The goal of the housing redesign was to decrease the vibrations at all measuring points in the frequency range 1000 to 3000 Hz.2.6 Results of the noise measurements The noise and vibration measurements described in section 2.3 were performed after optimizing the gears and transmission housing.The total sound power level decreased by 4 dB.2.7 Discussion and conclusions It seems to be possible to decrease the gear noise from a transmission by

decreasing the static loaded transmission error and/or optimizing the housing.In the present study, it is impossible to say how much of the decrease is due to the gear optimization and how much to the housing optimization.Answering this question would have required at least one more noise measurement, but time and cost issues precluded this.It would also have been interesting to perform the noise measurements on a number of transmissions, both before and after optimizing the gears and housing, in order to determine the scatter of the noise of the transmissions.Even though the goal of decreasing the gear noise by 10 dB was not reached, the goal of reducing the gear noise in the wheel loader cab to 15 dB below the overall noise was achieved.Thus the noise optimization was successful.3 SUMMARY OF APPENDED PAPERS 3.1 Paper A: Gear Noise and Vibration – A Literature Survey This paper presents an overview of the literature on gear noise and vibration.It is divided into three sections dealing with transmission error, dynamic models, and noise and vibration measurement.Transmission error is an important excitation mechanism for gear noise and vibration.It is defined as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate” [1].The literature survey revealed that while most authors agree that transmission error is an important excitation mechanism for gear noise and vibration, it is not the only one.Other possible time-varying noise excitation mechanisms include friction and bending moment.Noise produced by these mechanisms may be of the same order of magnitude as that produced by transmission error, at least in the case of gears with low transmission error [4].The second section of the paper deals with dynamic modeling of gearboxes.Dynamic models are often used to predict gear-induced vibrations and investigate the effect of changes to the gears, shafts, bearings, and housing.The literature survey revealed that dynamic models of a system consisting of gears, shafts, bearings, and gearbox casing can be useful in understanding and predicting the dynamic behavior of a gearbox.For

relatively simple gear systems, lumped parameter dynamic models with springs, masses, and viscous damping can be used.For more complex models that include such elements as the gearbox housing, finite element modeling is often used.The third section of the paper deals with noise and vibration measurement and signal analysis, which are used when experimentally investigating gear noise.The survey shows that these are useful tools in experimental investigation of gear noise because gears create noise at specific frequencies related to the number of teeth and the rotational speed of the gear.3.2 Paper B: Gear Test Rig for Noise and Vibration Testing of Cylindrical Gears Paper B describes a test rig for noise testing of gears.The rig is of the recirculating power type and consists of two identical gearboxes, connected to each other with two universal joint shafts.Torque is applied by tilting one of the gearboxes around one of its axles.This tilting is made possible by bearings between the gearbox and the supporting brackets.A hydraulic cylinder creates the tilting force.Finite element analysis was used to predict the natural frequencies and mode shapes for individual components and for the complete gearbox.Experimental modal analysis was carried out on the gearbox housing, and the results showed that the FE predictions agree with the measured frequencies(error less than 10%).The FE model of the complete gearbox was also used in a harmonic response analysis.A sinusoidal force was applied in the gear mesh and the corresponding vibration amplitude at a point on the gearbox housing was predicted.3.3 Paper C: A Study of Gear Noise and Vibration Paper C reports on an experimental investigation of the influence of gear finishing methods and gear deviations on gearbox noise and vibration.Test gears were manufactured using three different finishing methods and with different gear tooth modifications and deviations.Table3.3.1 gives an overview of the test gear pairs.The surface finishes and geometries of the gear tooth flanks were measured.Transmission error was measured using a single flank gear tester.LDP software from Ohio State University was used for transmission error computations.The test rig described in Paper B was used to measure gearbox noise and vibration for the different test gear pairs.The measurements showed that disassembly and reassembly of the gearbox with the same gear pair might change the levels of measured noise and vibration.The rebuild variation was sometimes of the same order of magnitude as the differences between different tested gear pairs, indicating that other factors besides the gears affect gear noise.In a study of the influence of gear design on noise, Oswald et al.[5] reported rebuild variations of the same order of magnitude.Different gear finishing methods produce different surface finishes and structures, as well as different geometries and deviations of the gear tooth flanks, all of which influence the transmission error and thus the noise level from a gearbox.Most of the experimental results can be explained in terms of measured and computed transmission error.The relationship between predicted peak-to-peak transmission error and measured noise at a torque level of 500 Nm is shown in Figure 3.3.1.There appears to be a strong correlation between computed transmission error and noise for all cases except gear pair K.However, this correlation breaks down in Figure 3.3.2, which shows the relationship between predicted peak to peak transmission error and measured noise at a torque level of 140 Nm.The final conclusion is that it may not be possible to identify a single parameter, such as peak-to-peak transmission error, that can be directly related to measured noise and vibration.3.4 Paper D: Gearbox Noise and Vibration −Influence of Bearing Preload The influence of bearing endplay or preload on gearbox noise and vibrations is investigated in Paper D.Measurements were carried out on a test gearbox consisting of a helical gear pair, shafts, tapered roller bearings, and a housing.Vibration measurements were carried out at torque levels of 140 Nm and 400 Nm with 0.15 mm and 0 mm bearing endplay and with 0.15 mm bearing preload.The results shows that the bearing endplay or preload influence gearbox vibrations.Compared with bearings

with endplay, preloaded bearings show an increase in vibrations at speeds over 2000 rpm and a decrease at speeds below 2000 rpm.Figure 3.4.1 is a typical result showing the influence of bearing preload on gearbox housing vibration.After the first measurement, the gearbox was not disassembled or removed from the test rig.Only the bearing preload/endplay was changed from 0 mm endplay/preload to 0.15 mm preload.Therefore the differences between the two measurements are solely due to different bearing preload.FE simulations performed by Sellgren and Åkerblom [6] show the same trend as the measurements here.For the test gearbox, it seems that bearing preload, compared with endplay, decreased the vibrations at speeds below 2000 rpm and increased vibrations at speeds over 2000 rpm, at least at a torque level of 140 Nm.3.5 Paper E: Gear Geometry for Reduced and Robust Transmission Error and Gearbox Noise In Paper E, gearbox noise is reduced by optimization of gear geometry for decreased transmission error.The optimization was not performed strictly mathematically.It was done by calculating the transmission error for different geometries and then choosing a geometry that seemed to be a good compromise considering not only the transmission error, but also other important characteristics.Robustness with respect to gear deviations and varying torque was considered in order to find gear geometry with low transmission error in the appropriate torque range despite deviations from the nominal geometry due to manufacturing tolerances.Static and dynamic transmission error as well as noise and housing vibrations were measured.The correlation between dynamic transmission error, housing vibrations, and noise was investigated in a speed sweep from 500 to 2500 rpm at constant torque.No correlation was found between dynamic transmission error and noise.4 DISCUSSION AND CONCLUSIONS Static loaded transmission error seems to be strongly correlated to gearbox noise.Dynamic transmission error does not seem to be correlated to gearbox noise in speed

sweeps in these investigations.Henriksson [7] found a correlation between dynamic transmission error and gearbox noise when testing a truck gearbox at constant speed and different torque levels.The different test conditions, speed sweep versus constant speed, and the different complexity(a simple test gearbox versus a complete truck gearbox)may explain the different results regarding correlation between dynamic transmission error and gearbox noise.Bearing preload influences gearbox noise, but it is not possible to make any general statement as to whether preload is better than endplay.The answer depends on the frequency and other components in the complex dynamic system of gears, shafts, bearings, and housing.To minimize noise, the gearbox housing should be as rigid as possible.This was proposed by Rook [8], and his views are supported by the results relating to the optimization of a transmission housing described in section 2.5.Finite element analysis is a useful tool for optimizing gearbox housings.5 FUTURE RESEARCH It would be interesting to investigate the correlation between dynamic transmission error and gearbox noise for a complete wheel loader transmission.One challenge would be to measure transmission error as close as possible to the gears and to avoid resonances in the connection between gear and encoder.The dropbox gears in a typical wheel loader transmission are probably the gears that are most easily accessible for measurement using optical encoders.See Figure 5.1.1 for possible encoder positions.Modeling the transmission in more detail could be another challenge for future work.One approach could be to use a model of gears, shafts, and bearings using the transmission error as the excitation.This could be a finite element model or a multibody system model.The output from this model would be the forces at the bearing positions.The forces could be used to excite a finite element model of the housing.The housing model could be used to predict noise radiation, and/or vibration at the attachment points for the gearbox.This approach would give absolute values, not just relative levels.REFERENCES [1] Welbourn D.B., “Fundamental Knowledge of Gear Noise −A Survey”, Proc.Noise & Vib.of Eng.and Trans., I Mech E., Cranfield, UK, July 1979, pp 9–14.[2] MackAldener M., “Tooth Interior Fatigue Fracture & Robustness of Gears”, Royal Institute of Technology, Doctoral Thesis, ISSN 1400-1179, Stockholm, 2001.[3] Ohio State University, LDP Load Distribution Program, Version 2.2.0, http://www.xiexiebang.com/ , 2007.[4] Borner J., and Houser D.R., “Friction and Bending Moments as Gear Noise Excitations”,SAE Technical Paper 961816.[5] Oswald F.B.et al., “Influence of Gear Design on Gearbox Radiated Noise”, Gear Technology, pp 10–15, 1998.[6] Sellgren U., and Åkerblom M., “A Model-Based Design Study of Gearbox Induced Noise”, International Design Conference – Design 2004, May 18-21, Dubrovnik, 2004.[7] Henriksson M., “Analysis of Dynamic Transmission Error and Noise from a Two-stage Gearbox”, Licentiate Thesis, TRITA-AVE-2005:34 / ISSN-1651-7660, Stockholm, 2005.[8] Rook T., “Vibratory Power Flow Through Joints and Bearings with Application to Structural Elements and Gearboxes”, Doctoral Thesis, Ohio State University, 1995.

第三篇：论文中英文摘要

论文中英文摘要

作者姓名：毛建猛

论文题目：Pushover分析方法的改进研究

作者简介：毛建猛，男，1983年10月出生，2005年8月师从于中国地震局工程力学研究所谢礼立教授，于2008年8月获博士学位。

中文摘要

如何选择合适的工程结构抗震分析和设计方法一直是地震工程领域引人关注的重要问题。随着基于性态抗震设计思想的提出和发展，作为一种简化的实现性态设计分析的方法，Pushover方法引起了广大学者和工程人员的兴趣，并得到了广泛的研究。本文针对以往Pushover方法的研究中存在的缺点和不足，对Pushover方法进行了改进，主要包括对模态Pushover方法的改进、对钢筋混凝土框架结构Pushover位移反应的修正、Pushover荷载模式与结构性态指标相关性的探讨、基于模态Pushover分析方法确定结构滞回耗能计算四个方面的问题。本论文主要研究内容和成果包括以下几个方面：

1.模态Pushover分析方法的一个重要假定是，结构在强震作用下进入非线性状态时，作用于结构的Pushover荷载模式保持不变；可是众所周知，结构发生屈服后，结构的动力特性会发生改变，结构遭受的地震荷载也会发生变化，因此各阶振型采用固定不变荷载模式的模态Pushover方法存在不足。本文提出将结构的第一振型荷载模式改进为两阶段加载模式，高阶振型荷载模式保持固定不变，对结构进行改进的模态Pushover分析。

2.建议了一种计算钢筋混凝土框架结构动力弹塑性位移反应的简便方法。通过对5个不同高度的钢筋混凝土框架结构在四类场地上80条地震动作用下的动力和静力弹塑性位移反应进行统计分析，给出了结构由静力弹塑性方法得到的目标位移估计动力时程方法得到的目标位移的修正公式。结果表明：场地条件对钢筋混凝土框架结构静力弹塑性位移反应和动力时程位移反应之间的关系影响显著；对于II类和III类场地，可以直接采用结构的静力弹塑性方法计算结果替代动力时程计算结果；对于I类场地和IV类场地，须采用修正公式对结构的静力弹塑性结果进行修正。

3.通过对4个不同高度的钢筋混凝土结构，分别进行了中等硬度场地上15条地震动作用下的非线性动力时程分析和不同荷载模式下的静力弹塑性分析，求解了结构的几个重要反应指标，包括能力曲线、顶端位移角及层间位移角、以及塑性铰分布，探讨了不同荷载模式对钢筋混凝土低层和高层结构反应指标的影响程度，建议了适用于钢筋混凝土低层和高层结构的Pushover荷载模式。

4.提出基于模态Pushover分析的结构滞回耗能计算方法。首先采用模态

Pushover分析计算结构各阶模态单自由度体系的特征参数，然后计算结构各阶模态单自由度体系对应的滞回耗能，并将其进行线性组合进而确定结构的滞回耗能，并与结构通过动力时程分析计算得到的滞回耗能进行比较，从而给出一种物理概念简单、计算操作方便的确定结构滞回耗能的方法。另外，为了便于计算结构各阶模态单自由度体系的滞回耗能，本文选取了国内外四类场地土上总计320条强震记录作为地震记录数据库，在统计分析的基础上，给出了对应于不同场地土和不同烈度区的单自由度体系等强度滞回耗能设计谱。

关键词：Pushover方法；能力谱方法；模态Pushover分析；水

平荷载模式；滞回耗能

Improvements on Pushover Analysis Procedure

Mao Jianmeng

ABSTRACT

How to select the adequate procedure for seismic analysis and design of structures is an essential problem in earthquake engineering field.With the development of Performance-based Seismic Design, Pushover Analysis procedure has attracted many scientists’ and engineers’ attentions and been widely used for its conceptual simplicity and computational attractiveness.To overcome the limitation of Pushover Analysis procedure, some improvements on this procedure were performed in this paper, including the improvement on Modal Pushover Analysis, the revision of target displacement from the pushover analysis for reinforced concrete frame, the correlation of structural response parameters with different lateral load patterns, and the computation of the structural hysteretic energy based on Modal Pushover Analysis etc.The main contents of this dissertation are as follows.1.There is an important assumption that the pushover load patterns keep unchanged even after the structure yields in Modal Pushover Analysis procedure.Recognized the adoption of invariable lateral force distributions in the Modal Pushover Analysis procedure, an improved modal pushover analysis procedure is presented in this paper to estimate the seismic demands of structures, considering the redistribution of inertia forces.It is suggested that after establishing the idealized bilinear curve, a pushover analysis is once again conducted for the first mode in two phases: before and after the structure yields.For the two phases, the structural elastic natural mode and the floor displacement vector at the initial yielding point are used as the displacement shape vector, respectively.2.The approximately estimating method of displacement of reinforced concrete(RC)frame from static pushover analysis(POA)is developed with that from non-linear response history analysis(RHA).Based on the statistic analyses of the RHA and POA results for five RC frames with different height under 80 ground motions recorded at four site conditions, the revised formula of displacements from POA is presented from RHA.The results show that the site soil condition has an important effect on the relation between RHA and POA response results.And the POA results for I and IV site condition should be revised with the formula given in this study while the POA results for II and III site condition can be approximately considered as same to the RHA results.3.The RHA under 15 ground motions recorded on the medium site condition and POA with different lateral load patterns are performed for four RC structures with different height.Several important response quantities are obtained from the RHA and POA, including capacity curves, top displacement ratios and story drift ratios, and location of plastic hinges.The influence of different load patterns on the structural performance demands is discussed for the low-and the high-wise structures.And the rational load patterns for the low-and the high-wise structures are also suggested.4.A simple procedure is presented in this paper for estimating hysteretic energy demands of MDOF systems based on the modal pushover analysis(MPA).Firstly, the characteristic parameters of the modal SDOF systems of structures are computed, and the hysteretic energy is calculated for the modal SDOF systems, then the hysteretic energy demand of structures is obtained by combining these modal demands.In addition, with statistic results of nonlinear analysis of SDOF for 320 ground motions recorded at four site conditions, the equal-strength hysteretic energy design spectra are presented for different site condition and intensity regions.Key words: pushover analysis procedure, capacity spectrum method, the

modal pushover analysis, lateral load patterns, hysteretic

energy

第四篇：论文-中英文摘要

摘要

随着信息时代的到来，信息高速公路的兴起，全球信息化进入了一个新的发展时期。人们越来越认识到计算机强大的信息模块处理功能，使之成为信息产业的基础和支柱。

车辆管理系统用计算机管理机动车辆的档案，运营管理以及驾驶员信息的一种计算机应用技术的创新，在计算机还未普及之前车辆管理都是由工作人员手工抄写的方式来操作的。现在一般的车辆管理都是采用计算机作为工具的实用的计算机智能化车辆管理程序来帮助工作人员进行更有效的机动车辆管理。车辆管理系统是典型的信息管理系统(MIS)，其开发主要包括后台数据库的建立和维护以及前端应用程序的开发两个方面。对于前者要求建立起数据一致性和完整性强、数据安全性好的库。而对于后者则要求应用程序功能完备，易使用等特点。经过分析，我们使用 MICROSOFT公司的 VISUAL BASIC开发工具,利用其提供的各种面向对象的开发工具，尤其是数据窗口这一能方便而简洁操纵数据库的智能化对象，首先在短时间内建立系统应用原型，然后，对初始原型系统进行需求迭代，不断修正和改进，直到形成用户满意的可行车辆管理系统系统。

关键字: 车辆管理系统;数据库;信息管理系统;智能化

Abstract

Along with the rise, world information that coming of information ages, information superhighway entered a new development period.People more and more know the mighty information of calculator to handle the function, and make the foundation that it become information industry with pillar.Vehicle Management System Computer used motor vehicles archives management, operation and management of a driver information computer applications innovation, Management has not yet popular in the computer before the vehicles are from the staff manual transcription to operate.Now the general management of the vehicles are used as a tool for computer computer intelligent vehicle management procedures to help staff more effective management of motor vehicles.Vehicle management system is a typical management information system(MIS), including its main development background to the establishment and maintenance of the database and front-end application development two.The request for the establishment of strong data consistency and integrity, good for the security of the data.For the latter request applications functions, such as easy to use features.After analysis, we use Microsoft visual basic development tool companies, the use of its various object-oriented development tools, especially data that can be easily accessible and concise window manipulation database intelligent objects, the first prototype application system in a short time and then, computation of the initial prototype system needs to constantly revise and improve until the formation of a viable system of user satisfaction.keywords :Vehicle management system;database;information management system;intelligentize

第五篇：论文中英文摘要格式

附件6

校优博、优硕学位论文中英文摘要格式 作者姓名：张三（宋体 四号）

论文题目：xxxxxxxxxxxx的研究（宋体 四号）

作者简介：：张三，男，xxxx年xx月出生，xxxx年xx月师从于xx大学xxx教授，于xxxx年xx月获博士学位。

中文摘要

在XXXXXXXXX技术中，具有较强XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.其研制和开发有了长足的进展。„„„„„„„

（正文：宋体 小四，博士约三千字，硕士约2千字）

关键词：（宋体 四号）

Study on the …(英文题目 字号：“Times New Roman” 三号)

Zhang San(姓名拼音 字号：“Times New Roman” 四号)

ABSTRACT

The only high temperature superconductorxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx..This is sufficient for ………….…

（正文字号：“Times New Roman” 小四，约三千字）

Key borad:(字号：“Times New Roman” 四号)