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2012, 42(4): 365-365. doi: 10.6052/1000-0992-2012-4-20120401

Abstract(1018)

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ADVANCES AND TRENDS IN DYNAMICS AND CONTROL OF SPACECRAFTS

HUANG Wenhu, CAO Dengqing, HAN Zengyao

2012, 42(4): 367-394. doi: 10.6052/1000-0992-11-171

Abstract(4048)

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The research on dynamics and control of spacecrafts for the purpose of establishing effective strategies to ensure reliable operation of spacecrafts at each stage plays a prominent role in the developments of the space technology. The space technology is developing rapidly, and showing more and more diversities, in which functions and structures of the spacecrafts become more and more complicated. The appearance of large size space stations and micro-satellites, and the developments of deep space explorations have brought about multi-couplings, nonlinearities, extreme environments, and extremely high flexibilities. The research of dynamics and control of spacecrafts is developing thoroughly in several directions, including theoretical analysis, numerical simulations, and experimental simulations. In this paper, a review is given of foundamental problems and their recent developments in dynamics and control of the multi-spacecraft, the whole system, and the components of one single spacecraft. It is mainly focused on summarizing the existing methods and results of dynamic modeling, response analysis, and vibration control of spacecrafts in different application areas, and with different hierarchical structures. Moreover, some scientific problems in need of further study, and prospects for new development directions in this field are presented at the end of this paper.

RESEARCH EVOLUTION ON THE TEST VERIFICATION OF SPACECRAFT DYNAMIC MODEL

DING Jifeng, HAN Zengyao, MA Xingrui

2012, 42(4): 395-405. doi: 10.6052/1000-0992-10-012

Abstract(1962)

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Coupled Load Analysis (CLA) is a key step during spacecraft design process, the result of which is the most important reference to structure design, estimation of test force/acceleration specification and the approval of the spacecraft's flight, a test verified dynamic model of the spacecraft is the base of the Coupled Load Analysis. For complex spacecraft system, model verification task is a very challenge. Firstly, a systematic model verification process is presented. And then, several critical issues, including structure dynamics test, model correlation and model updating, are discussed. Finally, according to the space engineering requirement, some emphases that need to research in the future are proposed.

REVIEWS IN STRUCTURAL DYNAMICS ANALOGY TECHNIQUE OF LAUNCH VEHICLE

PAN Zhongwen, ZENG Yaoxiang, LIAN Yongzheng, XING Yufeng

2012, 42(4): 406-415. doi: 10.6052/1000-0992-12-063

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First in this paper, based on different kinds of launch vehicles, domestic and overseas overall modal analysis and experiments verification are respectively reviewed. Then dynamics modeling techniques are respectively summarized from three directions, such as dynamics modeling of cylindrical shell- stiffened, dynamics simulation of liquid propellant, prediction methods of local mode shape-slope. Finally, further research directions are suggested based on the development needs of structural dynamics of launch vehicles.

PROGRESSES IN RESEARCH ON COUPLED ANALYSIS TECHNOLOGY FOR SPACE VEHICLE AND LAUNCH VEHICLES

QIU Jibao, ZHANG Zhengping, LI Haibo

2012, 42(4): 416-436. doi: 10.6052/1000-0992-11-203

Abstract(2182)

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With focus laid on loads analysis, some progresses of structural dynamics in the field of space vehicle design are summarized. The paper first presented some fundamental ideas of load analysis which has been applied in space vehicle / launch vehicle coupling systems. And then load analysis methods were explored in the following three directions:1) Approximate initial load analysis methods by means of basis excitation theory in which coupling effects of the space vehicle / launch vehicles are neglected;2) A branch modes synthesis method for the coupled space vehicle / launch vehicle system with the coupling effects taken into account. Based on the interface acceleration of constraint modes mass, the load estimation of the space vehicle / launch vehicle coupled system was derived analytically. Furthermore, if only static constraints modes mass is considered, the reduced equation (as a special case of this method) is actually identical to the equation derived by Chen using FEM. Furthermore, a new technique for space vehicle load transient analysis was also established. With the technique, previous analyzing results of space vehicle / launch vehicle coupling systems can be extended to new coupling systems between the same launch vehicle and a new space vehicles;3) A modal synthesis method for the space launch / launch vehicle coupled systems. Several modal synthesis methods were studied, the fixed-interface modal synthesis method was first presented，and the method was applied to Ariane-5 launch vehicle dynamic response analysis, a new method for deriving dynamic response of the space launch / launch vehicle system was then given based on coupling interface synthesis;Finally, verification techniques of the load analysis methods were elucidated. After a brief discussion of the importance of the verification techniques, a new technology of structure dynamic test simulation is proposed to combine the experimental results with the theoretical analyzing results. This is a set of new techniques for updating mathematics model, which is named as synthesis techniques based on the substructure experimental modeling. The approach has been applied to the modeling of such complex structures as a large strap-on launch vehicle Long March 2E (LM-2E) and a 40 T shaker system.The proposed techniques were demonstrated with LM-2E as follows: the predicted modes were derived before the modal test of real full scale LM-2E launch vehicle; and the modes were then compared with actual test results obtained thereafter. The two results turned out to be highly consistent between each other. The experiment proves that the modal parameters of the LM-2E had been successfully reproduced by the proposed modal test simulation techniques，and the reliability of the proposed techniques is thus verified. The vibration test simulation techniques of a 40 T shaker were also discussed. Key simulation techniques for the vibration test are summarized, including the modification technique for the shaker FEA mathematics model; the simulation technique of the table-board control for vibrating tests of a 40 T shaker system and the simulation technique of D satellite shaker vibration tests.

ADVANCES IN STUDY ON JOINT BEHAVIOR OF CLAMP BAND AND DYNAMICS OF SPACECRAFT-LAUNCH VEHICLE-CLAMP BAND COUPLING SYSTEM

QIN Zhaoye, CHU Fulei, YAN Shaoze

2012, 42(4): 437-444. doi: 10.6052/1000-0992-11-035

Abstract(2173)

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Clamp band joint is widely used as the mechanical attachment of spacecraft to the launch vehicle in the aerospace industry. The loads are transmitted between the spacecraft and the launch vehicle through frictional contacts between the components of the clamp band joint to realize the connection under pretightening forces. The contact and friction behaviors vary along with the variation of external loads, leading to the nonlinearity of the clamp band joint stiffness and consequently affecting the load capability and the dynamic characteristics of the launching system. In this paper, the study on local nonlinearity of the clamp band joint and its effects on the dynamics of the launching system are reviewed. Firstly, researches related to the joint characteristics of the clamp band joint are examined, where the load capability and the joint stiffness are discussed in detail. Then, studies on the dynamics of the spacecraft-launch vehicle-clamp band coupling system is summarized with focus laid on the representation of the clamp band joint in the launching system model and its effects on the dynamics of the launching system. Finally, existing problems and certain topics in need of further studies are pointed out.

RESEARCH PROGRESS ON FULL-FREQUENCY PREDICTION TECHNIQUES OF SPACECRAFT'S MECHANICAL ENVIRONMENT

ZOU Yuanjie, HAN Zengyao, ZHANG Jin

2012, 42(4): 445-454. doi: 10.6052/1000-0992-11-075

Abstract(1828)

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The mechanical environment prediction technique of spacecraft is critical to spacecraft system design and structure design, especially to spacecraft for first launch, since it lacks telemetry data from similar spacecraft and thus could only rely on effective prediction means to establish the ground test scheme and related test requirements. No individual analysis method could get accurate prediction results for full-frequency bands currently, because spacecraft at launch experiences full-frequency dynamic loads, which bring about great discrepancy of structure responses at different frequencies. The full-frequency mechanical environment prediction technique is described regarding low-frequency, mid-frequency and high-frequency band, respectively. In the end, according to the requirement of domestic spacecraft engineering, the main research directions are presented for the full-frequency mechanical environment prediction.

RESEARCH ON THE ESTIMATION OF FORCE SPECIFICATIONS FOR FORCE-LIMITED VIBRATION TESTING

LI Zhengju, MA Xingrui, HAN Zengyao

2012, 42(4): 455-463. doi: 10.6052/1000-0992-12-043

Abstract(1968)

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In traditional vibration tests, the payload is mounted to a rigid fixture and the interface acceleration is controlled to a specified level based on a conservative estimate of the expected flight environment. The forcelimited vibration testing is developed to alleviate the over-testing associated with impedance differences between the flexible flight mounting and the rigid test fixture. Force-limited vibration testing technology is composed of the calculation method of force specifications and the force-limited control technology in vibration testing, and the calculation of the force specifications is the most critical step of the force-limited vibration testing. This paper presents force-limited vibration testing technology and the calculation method of force specifications, and surveys comprehensively the development of the technology. And finally, according to the requirement of domestic space engineering, several research directions in force-limited vibration testing technology are stressed.

AN OVERVIEW OF STRUCTURAL STRENGTH DESIGN METHODS FOR SPACECRAFTS IN RANDOM VIBRATION ENVIRONMENT

ZHANG Yumei, HAN Zengyao, ZOU Yuanjie

2012, 42(4): 464-471. doi: 10.6052/1000-0992-12-016

Abstract(2457)

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Random vibration is an important part of spacecraft structure design. Now, the main method used in the structural strength design of spacecrafts is equivalent static design method. Its equivalent principles include equivalent acceleration response, equivalent displacement response and equivalent stress response. Respective theories, methods, domestic and overseas research status, advantages and disadvantages and engineering applications are presented. The design method based on the peak values of displacement and stress response is recommended. And the problems in need of further research are finally suggested.

REVIEWS ON LIQUID SLOSHING DYNAMICS AND LIQUID-STRUCTURE COUPLING DYNAMICS IN LIQUID-FILLED SPACECRAFTS

LI Qing, WANG Tianshu, MA Xingrui

2012, 42(4): 472-481. doi: 10.6052/1000-0992-12-019

Abstract(2540)

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As the capacity of launch vehicles, the lifespan of satellites and the complexity of deep space missions increase, the mass proportions of liquid propellant in spacecrafts are enhanced accordingly. Sloshing of liquid propellant in spacecrafts might affect the motion stability and the attitude and orbit control system, which is of particular concern in spacecraft dynamics. The sloshing liquid in a liquid-filled spacecraft is a distributed parameter system which is theoretically infinite dimensional, however, a simplified and reduced model is preferred in engineering. Therefore, equivalent mechanical models for liquid sloshing are continually studied. Moreover, the fluid-structure interaction between liquid propellant and tanks has important effects on the structural dynamics of spacecrafts, which is also of concern in liquid-filled spacecraft dynamics. First in this paper, the liquid sloshing studies are respectively reviewed regarding theoretical researches, numerical studies, experimental investigations and equivalent mechanical models. Then the numerical methods and application programs in fluid-structural interaction modeling are summarized. Finally, further research directions are suggested based on the development needs of spacecraft engineering.

Review of dynamics and control of stratospheric airships

LI Zhibin, WU Lei, ZHANG Jingrui, LI Yong

2012, 42(4): 482-493. doi: 10.6052/1000-0992-11-092

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The developmental history and research status of airship are briefly presented. Compared with the traditional aircraft, spacecraft, submarines and low altitude airship, the flight principle of stratospheric airships is elaborated. From the point of view of basic motion model and the complex force condition, progresses in dynamics research are discussed systematically, including aerodynamics research, static analysis, thermodynamic analysis, flexible body dynamics and the study of fluid-solid coupling. Then the progress in airship control methods is reviewed, including the small disturbance linearization control, input output feedback linearization control, the Lyapunov nonlinear stability based control and other control method. Finally, it is proposed to reinforce research efforts in six directions in the field of stratospheric airship dynamics and control.

REVIEW OF《DIMENSIONAL ANALYSIS》

LU Xiaobing

2012, 42(4): 494-495. doi: 10.6052/1000-0992-2012-4-20120412

Abstract(1447)

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A BRIEF INTRODUCTION OF FINISHED KEY PROJECTS ON MECHANICS IN 2011

ZHAN Shige, ZHANG Panfeng, L? Shouqin, ZHANG Wenming

2012, 42(4): 496-500. doi: 10.6052/1000-0992-2012-4-20120413

Abstract(1035)

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