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A review of passive thermal management of LED module

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Journal of Semiconductors 2011年第1期32卷 57-60页

作者：叶怀宇 sau koh Henk van Zeijl A.W.J.Gielen 张国旗 Delft Institute of Microsystems and Nanoelectronics(Dimes) Delft University of Technology Materials Innovation Institute(M2i) Mekelweg 22628 CDDelftNetherlands Netherlands Organization for Applied Scientific Research(TNO) De Rondom 1 5612 APEindhovenNetherlands

Recently, the high-brightness LEDs have begun to be designed for illumination application. The increased electrical currents used to drive LEDs lead to thermal issues. Thermal management for LED module is a key design parameter as high operation temperature directly affects their maximum light output, quality, reliability and life time. In this review, only passive thermal solutions used on LED module will be studied. Moreover, new thermal interface materials and passive thermal solutions applied on electronic equipments are discussed which have high potential to enhance the thermal performance of LED Module.

关键词： HB LEDs LED module thermal management passive thermal solution thermal interface material

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先进SSL系统可靠性预测框架（英文）

先进SSL系统可靠性预测框架（英文）

Fundamental modeling issues on benchmark structure for structural health monitoring

第七届中国国际半导体照明论坛

作者： Cadmus Yuan L.J.M.G(Ardi)Dortmans A.W.J.Gielen sau koh Willem van Driel 张国旗荷兰应用科学研究组织代尔夫特理工大学计算机系统和纳米电子学学院

The smart lifetime approach is to manipulate material system in SSL system to achieve the designed *** one of the basic building block of smart lifetime,we propose a system reliability prediction framework for solid state lighting（SSL）,which is capable of predicting the performance of system reliability as well as the component level failure *** framework is based on the advanced statistic approaches,and consists of three major building blocks:fault tree,Bayesian Belief Net（BBN） and Markov *** the booming of the professional energy conservation service company（ESCO） and energy management contract（EMC） business,the demand of system reliability prediction with the detail information of the component failure distribution is foreseen,and this framework will be helpful for ESCOs to make a robust system maintenance plan.

关键词： Smart Lifetime:System Reliability Markov chain/process Energy management contract(EMC)

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Science China(Technological Sciences) 2009年第7期52卷 1999-2008页

作者： HU sau-Lon James Department of Ocean Engineering University of Rhode Island Narragansett RI 02882-1197 USA

The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems, and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detec- tion, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.

关键词： benchmark structural health monitoring damage detection modeling error

Employing incomplete complex modes for model updating and damage detection of damped structures

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Science China(Technological Sciences) 2008年第12期51卷 2244-2258页

作者： HU sau-Lon James Department of Ocean Engineering University of Rhode Island

In the study of finite element model updating or damage detection,most papers are devoted to undamped ***,their objective has been exclusively restricted to the correction of the mass and stiffness *** contrast,this paper performs the model updating and damage detection for damped structures.A theoretical contribution of this paper is to extend the cross-model cross-mode(CMCM) method to simultaneously update the mass,damping and stiffness matrices of a finite element model when only few spatially incomplete,complex-valued modes are *** studies are conducted for a 30-DOF(degree-of-freedom) cantilever beam with multiple damaged elements,as the measured modes are synthesized from finite element *** numerical results reveal that applying the CMCM method,together with an iterative Guyan reduction scheme,can yield good damage detection in *** the measured modes utilized in the CMCM method are corrupted with irregular errors,assessing damage at the location that possesses larger modal strain energy is less sensitive to the corrupted modes.

关键词： incomplete complex modes model updating damage detection CMCM damped structures

Refinement of reduced-models for dynamic systems

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Progress in Natural Science:Materials International 2008年第8期18卷 993-997页

作者： sau-Lon James Hu Department of Ocean Engineering University of Rhode Island Narragansett RI 02882-1197 USA

A refinement procedure for the reduced models of structural dynamic systems is presented in this article. The refinement procedure is to "tune"the parameters of a reduced model, which could be obtained from any traditional model reduction scheme, into an improved reduced model. Upon the completion of the refinement, the improved reduced model matches the dynamic characteristics-the chosen structural frequencies and their mode shapes-of the full order model. Mathematically, the procedure to implement the model refinement technique is an application of the recently developed cross-model cross-mode (CMCM) method for model updating. A numerical example of reducing a 5-DOF (degree-of-freedom) classical mass-spring (or shear-building) model into a 3-DOF generalized mass-spring model is demonstrated in this article.

关键词： Model reduction Model re?nement Finite element method Modal analysis Structural dynamics

Parametric Analysis of A Submerged Cylindrical Shell Subjected to Shock Waves

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China Ocean Engineering 2007年第1期21卷 125-136页

作者：李上明 FAN sau-Cheong Engineering Mechanics Research Center School of Civil Engineering and ArchitectureNanchang University Protective Technology Research Center School of Civil and Environmental EngineeringNanyang Technological University

In this study, an FEM-SBFEM （scaled boundary finite element method） coupling procedure proposed by Fan et al. （2005） is adopted to obtain the dynamic responses of a submerged cylindrical shell subjected to plane step or exponential acoustic shock waves. The coupling procedure can readily be applied to three-dimensional problem, however for clarity, the problems to be presented are hmited to two-dimeusional domain. In the analyses, the cylindrical shell is modeled by simple beam elements （using FEM）, while the effects of the surrounding infinite fluid is modeled by the SBFEM. In it, no free surface and seabed are involved. Compared with Fan and his co-authors＇ works, the FEM-SBFEM coupling procedure is further verified to be feasible for shock waves by benchmark examples. Furthermore, parametric studies are performed and presented to gain insight into effects of the geometric and material properties of the cylindrical shell on its dynamic responses.

关键词： cylindrical shell FEM-SBFEM coupling shock wave infinite fluid parametric study

The Optimal Design of TMD for Offshore Structures

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China Ocean Engineering 1999年第2期14卷 133-144页

作者： sau Lon James HU Tomotsuka TAKAYAMA Dept. of Ocean Engrg. University of Rhode Island RI02881 Professor Professor Disaster Prevention Res. Inst. Kyoto Univ. Gokasho Uji Kyoto 611-0011 Japan.

This paper presents the optimal design procedure of Tuned Mass Damper (TMD) for reducing vibration of an actual steel jacket offshore platform excited by random wave loading. In this study, a frequency domain is taken. The force on the structure is determined by use of the linearized Morison equation for an input Power Spectral Density (PSD) of wave elevation. The sensitivity of optimum values of TMD to characteristic parameters of random wave spectrum is analyzed. An optimized TMD design for the modeled platform is given based on design conditions and the findings of the study.

关键词： tuned mass damper design Morison equation power spectral density offshore structures

Optimal Active Control of Wave-Induced Vibration for Offshore Platforms

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China Ocean Engineering 2001年第1期16卷 1-14页

作者：李华军 sau-LonJamesHU TomotsukaTAKAYAMA College of Engineering Ocean University of Qingdao Department of Ocean Engineering University of Rhode Island Island 02882 USA Disaster Prevention Research Institute Kyoto University

An obvious motivation of this paper is to examine the effectiveness of the lateral vibration control of a jacket type offshore platform with an AMD control device, in conjunction with H-2 control algorithm, which is an optimal frequency domain control method based on minimization of H-2 norm of the system transfer function In this study, the offshore platform is modeled numerically by use of the finite element method, instead of a lumped mass model This structural model is later simplified to be single-degree-of-freedom (SDOF) system by extracting the first vibration mode of the structure. The corresponding 'generalized' wave force is determined based on an analytical approximation of the first mode shape function, the physical wave loading being calculated from the linearized Morison equation. This approach facilitates the filter design for the generalized force. Furthermore, the present paper also intends to make numerical comparison between H-2 active control and the corresponding passive control using a TMD with the same device parameters.

关键词： active control offshore platform vibration wave loading

A Novel Approach for Evaluating Nonstationary Response of Dynamic Systems to Stochastic Excitation

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Journal of Ocean University of China 2020年第4期19卷 781-789页

作者： CAO Qianying HU sau-Lon James LI Hewenxuan College of Engineering Ocean University of ChinaQingdao 266100China Department of Ocean Engineering University of Rhode IslandNarragansettRI 02882USA College of Engineering University of Rhode IslandKingstonRI 02881USA

The transient state of a dynamic system,such as offshore structures,to random excitation is always *** studies have contributed to evaluating response covariances at the transient state of a linear multi-degree-of-freedom(MDOF)system to random excitations,but a closed-form solution was not available unless the excitation was assumed to be a physically unrealizable white noise *** study derives explicit,closed-form solutions for the response covariances at the transient state by using a pole-residue(PR)approach operated in the Laplace domain when the excitations are assumed to be stationary random processes described by physically realizable spectral density *** using the PR method,we can analytically solve the triple integral in evaluating the nonstationary response *** this approach uses the poles and residues of system transfer functions,rather than the conventional mode superposition technique,the method is applicable to MDOF systems with non-classical damping *** application of the proposed method is demonstrated for multi-story shear buildings to stochastic ground acceleration characterized by the Kanai–Tajimi spectral density function model,and a numerical example is provided to illustrate the detailed *** numerical integrations are required for computing the response covariances as the exact closed-form solution has been *** correctness of the proposed method is numerically verified by Monte Carlo simulations.

关键词： linear systems transient state nonstationary response pole residue