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Formulation of Reduction Rate for Ultimate Compressive Strength of stiffened panel Induced by Opening

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China Ocean Engineering 2014年第4期28卷 557-568页

作者：于昌利 LEE Joo-sung School of Naval Architecture and Ocean Engineering Harbin Institute of Technology School of Naval Architecture and Ocean Engineering University of Ulsan

The main objective of this study is to numerically investigate the characteristics of ultimate compressive strength of stiffened panels with opening and also to fit the design-oriented formulae. For this purpose, three series of well executed experimental data on longitudinally stiffened steel plates with and without opening subjected to the uniform axial in-pane load which is carried out to study the buckling and post-buckling up to the final failure are chosen. Also, a nonlinear finite element method capable of efficiently analyzing the large elasto-plastic deflection behavior of stiffened panels is developed and used for simulation. The feasibility of the present simulation process is confirmed by a good agreement with the experimental results. More case studies are developed employing the simulation process to analyze the influence of various design variables on the reduction rate of ultimate strength of stiffened panel induced by opening. Based on the computed results, two design formulae are fitted and the accuracy of design formulae is studied. Furthermore, the viability of the design formulae for practical engineering is proved.

关键词： stiffened panel opening reduction rate non-linear analysis formulae fitting

Guided wave propagation analysis in stiffened panel using time-domain spectral finite element method

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Chinese Journal of Aeronautics 2022年第10期35卷 208-221页

作者： Zexing YU Chao XU Jiaying SUN Fei DU School of Astronautics Northwestern Polytechnical UniversityXi'an 710072China Qingdao R&D Institute Northwestern Polytechnical UniversityQingdao 266200China

stiffened panels have been widely utilized in fuselages and wings as critical load-bearing components. These structures are prone to be damaged under long-term and extreme loads, and their health monitoring has been a common concern. The guided wave-based monitoring method is regarded as an efficient approach to detect the damage in stiffened plates because of its wide monitoring range and high sensitivity to micro-damage. Efficient simulation of wave propagation can theoretically demonstrate the detection mechanism of the method. In this study, a Time-Domain Spectral Finite Element Method(TD-SFEM) is adopted to study the wavefield in stiffened plates,where continuous Absorbing Layers with Increasing Damping(ALID) strategy is proposed to circumvent the disturbance of reflected waves on boundaries. After the convergence analysis, the developed TD-SFEM with ALID is validated by the finite element method first. Then, wave scattering and the influence of the stiffener are investigated in detail by comparing the results with the non-stiffened structure. Finally, the effects of the parameters of the stiffener, such as the height and width, on wave propagation are studied, respectively. The results illustrate that the proposed TDSFEM with ALID is an efficient approach to study the wave propagation in the stiffened plate and can reveal the mechanism of influence of the stiffener. It is found that the height of the stiffener changes the interference of wavefield in the plate, while the effects of the width are mainly in wave scattering and mode conversion.

关键词： Absorbing layers with increasing damping Guided waves stiffened panel Time-domain spectral finite element Wave propagation

Numerical Analysis of Static Performance Comparison of Friction Stir Welded versus Riveted 2024-T3 Aluminum Alloy stiffened panels

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 761-767页

作者： SHAO Qing HE Yuting ZHANG Teng WU Liming Aeronautics and Astronautics Engineering College Air Force Engineering University

Most researches on the static performance of stiffened panel joined by friction stir welding（FSW） mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method（FEM） is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted panel

关键词： friction stir welding rivet fastening stiffened panel stability performance finite element method(FEM)

Study on Ultimate Compressive Strength of Aluminium-Alloy Plates and stiffened panels

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Journal of Marine Science and Application 2020年第4期19卷 534-552页

作者： Bin Liu Van Tuyen Doan YGarbatov Weiguo Wu C.Guedes Soares Green&Smart River-Sea-Going Ship Cruise and Yacht Research CentreWuhan University of TechnologyWuhan 430063China Faculty of Shipbuilding Vietnam Maritime UniversityHaiphongVietnam Centre for Marine Technology and Ocean Engineering(CENTEC) Instituto Superior TécnicoUniversidade de Lisboa1049-001 LisbonPortugal

This work reviews the ultimate compressive strength of aluminium plates and stiffened *** effect of boundary condition,initial imperfection,welding-induced residual stress and heat-affected zone are *** the effect of manufacturing technology lacks in the literature,this effect is analysed employing the finite element method,considering the technology of welding and integrated *** numerical analyses have shown that the ultimate strength of the integrated extruded stiffened panel is relatively higher than the one of the traditional welded panel.

关键词： Ultimate strength Compressive load stiffened panel Aluminiumalloy Review

Review on residual stress and its effects on manufacturing of aluminium alloy structural panels with typical multi-processes

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Chinese Journal of Aeronautics 2023年第5期36卷 96-124页

作者： Yong LI Wanni GAN Wenbin ZHOU Dongsheng LI School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Shenzhen Institute of Beihang University Shenzhen 518057China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

In the aerospace industry,integrated aluminium alloy plates and stiffened panels with high accuracy and performance attract significant *** manufacture these panels as integrity with high accuracy,multiple processes need to be utilised,such as machining,welding and *** the whole manufacturing chain,residual stresses can be generated and redistributed in the components among different *** residual stress would significantly affect the shapes and properties of the final ***,these great effects are not well considered in the design and manufacturing *** paper aims to draw a general understanding of the residual stress generated in the pre-manufacturing processes and its effects on subsequent manufacturing *** mechanisms and distributions of residual stresses generated in typical premanufacturing processes of structural panels,including machining,welding and additive manufacturing(AM),are firstly *** detailed effects of generated residual stresses on distortion and application properties in subsequent manufacturing processes are then *** addition,current methods developed for the investigation of residual stress effect in multi-processes manufacturing are critically reviewed,including experimental,analytical,finite element(FE)and machine learning ***,the future development trend of methods for residual stress consideration and control in the design of manufacturing processes is summarised,providing comprehensive guidance to achieve the high accurate manufacturing of aluminium alloy structural components.

关键词： Residual stress stiffened panel Aluminium alloy Multi-processes manufacturing Machining Welding Additive manufacturing

Residual Strength of stiffened LY12CZ Aluminum Alloy panels with Widespread Fatigue Damage

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Chinese Journal of Aeronautics 2008年第1期21卷 48-52页

作者：李仲葛森吕国志陈莉丁惠良西北工业大学航空学院陕西西安710072

Experimental and analytical investigations on the residual strength of the stiffened LY12CZ aluminum alloy panels with widespread fatigue damage （WFD） are conducted. Nine stiffened LY12CZ aluminum alloy panels with three different types of damage are tested for residual strength. Each specimen is pre-cracked at rivet holes by saw cuts and subjected to a monotonically increasing tensile load until failure is occurred and the failure load is recorded. The stress intensity factors at the tips of the lead crack and the adjacent WFD cracks of the stiffened aluminum alloy panels are calculated by compounding approach and finite element method （FEM） respectively. The residual strength of the stiffened panels with WFD is evaluated by the engineering method with plastic zone linkup criterion and the FEM with apparent fracture toughness criterion respectively. The predicted residual strength agrees well with the experiment results. It indicates that in engineering practice these methods can be used for residual strength evaluation with the acceptable accuracy. It can be seen from this research that WFD can significantly reduce the residual strength and the critical crack length of the stiffened panels with WFD. The effect of WFD crack length on residual strength is also studied.

关键词： stiffened panel widespread fatigue damage (WFD) residual strength stress intensity factor plastic zone linkup criterion

A Study on the Effect of Welding Sequence in Fabrication of Large stiffened Plate panels

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Journal of Marine Science and Application 2011年第4期10卷 429-436页

作者： Pankaj Biswas D. Anil Kumar N.R.Mandal M.M.Mahapatra Department of Mechanical Engineering Department of Ocean Engineering & Naval Architecture

Welding sequence has a significant effect on distortion pattern of large orthogonally stiffened panels normally used in ships and offshore structures. These deformations adversely affect the subsequent fitup and alignment of the adjacent panels. It may also result in loss of structural integrity. These panels primarily suffer from angular and buckling distortions. The extent of distortion depends on several parameters such as welding speed, plate thickness, welding current, voltage, restraints applied to the job while welding, thermal history as well as sequence of welding. Numerical modeling of welding and experimental validation of the FE model has been carried out for estimation of thermal history and resulting distortions. In the present work an FE model has been developed for studying the effect of welding sequence on the distortion pattern and its magnitude in fabrication of orthogonally stiffened plate panels.

关键词： elasto-plastic analysis welding distortion 3-D finite element analysis stiffened panel weldingsequence

Amended disturbance observer design and its application in active vibration control for piezoelectric structure

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Amended disturbance observer design and its application in a...

Ultimate Strength Assessment of a Tanker Hull Based on Experimentally Developed Master Curves

第25届中国控制与决策会议

作者： Li shengquan Zhao Rong Li Juan Mo Yueping School of Energy and Power Engineering Yangzhou University School of Automation Southeast University

ISBN: (纸本)9781467355339

To improve the vibration suppression performance of LQR based real structural vibration control system, an amended disturbance observer design method was presented for an all-clamped stiffened panel with unmodeled error, harmonic effect and acceleration sensor noise. Then, a compound control strategy is proposed to suppress the structural vibration excited by external sinusoidal disturbance, via combing the amended DOB and the traditional LQR optimized by the chaos sequence. Both theory analysis and vibration control experiment results have shown good disturbances and measurement noise rejection performances of the proposed active vibration control strategy.

关键词： active vibration control disturbance observer (DOB) stiffened panel piezoelectric optimal control

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Journal of Marine Science and Application 2013年第2期12卷 127-139页

作者： Mingcai Xu Y. Garbatov C. Guedes Soares Centre for Marine Technology and Engineering (CENTEC) lnstituto Superior TOcnico Technical University of Lisbon Lisbon Portugal

A geometrically similar scaling was made from small-scale specimen to full-scale stiffened panels and then their collapse behaviour is investigated. It is considered that the stiffened panel compressive ultimate strength test was designed according to geometrical scaling laws so that the output of the test could be used as representative of the stiffened panels of the compressive zone of a tanker hull subjected to vertical bending moment. The ultimate strength of a tanker hull is analysed by a FE analysis using the experimentally developed master stress-strain curves which are obtained by the beam tension test and the compressive test of the stiffened panel, and are then compared with the result achieved by the progressive collapse method.

关键词： ship hull tanker hull stiffened panel ultimate strength scaling laws similitude analysis