Yuqi Wang

Nanyang Technological University, Singapore, Singapore

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Publications (11)7.43 Total impact

  • K.H. Low, Yuqi Wang
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    ABSTRACT: Purpose – To present a method to model woven fibre reinforced metal matrix composite for multilayer circuit boards. Design/methodology/approach – This paper presents a hybrid modelling method to model multilayer multimaterial composites with the combination of metallic and woven composite plies. Firstly, 3D unit cells of woven composite are idealized as orthotropic plies, while metallic layers are taken as isotropic plies. Secondly, the idealized composite plies and metallic plies are modelled into a 2D multilayer finite element (FE). Lastly, scalar damage parameters are used for damage modelling. Findings – Based on this method, static and dynamic analysis of multilayer composite can be performed at both micro and board levels. Meanwhile, the hybrid model illustrates a good agreement with the experimental results and good computational efficiency required for FE simulation. Conceptually, this study is aimed to provide an efficient damage modelling techniques for laminate composites and flexible modelling methodology for further development of new composite material systems. Research limitations/implications – Damaging testing and simulation is not involved, although damaging modelling method is presented. Originality/value – This model has high flexibility and efficiency: the micro structure and properties of reinforced fibres, polymer matrix and metallic plies can be changed conveniently in 3D mechanics unit-cell model; the 2D structure of geometry model provides a high-computational efficiency in the numerical simulation. The presented work also provides the damage modelling methods, multi-linear damage law and scalar damage parameters, to simulate damage behaviour after impact.
    Circuit World 05/2008; 34(2):12-20. · 0.60 Impact Factor
  • K.H. Low, Yuqi Wang
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    ABSTRACT: Purpose – The paper aims to present a modeling method for multi-layer, multi-material printed circuit boards (PCBs) in both micro-structure and board levels. Design/methodology/approach – The method incorporates a multilayer finite element model that is established in two parts: the first part is an elasto-plastic damaging model, which is presented to model metallic plies in the multi-layer PCBs, while the second is a bi-phase model for glass-fiber/epoxy-resin composite ply with fiber/matrix structure. Findings – Numerous composite parts and complex material properties of multi-layer PCBs complicate the reliability of the simulation. Therefore, the board level simulation and the micro-structure modeling cannot be performed at the same time. A multi-layer FEM code can solve this problem: with the use of bi-phase and elasto-plastic plies in this code, the micro-structure and board-level modeling for multi-layer PCBs can be incorporated. Research limitations/implications – With the implementation of a virtual boundary method, the current multi-layer model can be combined with the unit-cell modeling method to perform detailed analysis at the micro-structure level. Originality/value – This paper presents a method for multi-layer PCB modeling at both the micro-structure and board levels. It provides a way to individually design the fabric types and the properties of glass fibers, epoxy resin, and copper foil in PCBs, to meet specific reliability requirements. With the proposed modeling, the static and shock responses of optimized PCBs can be analyzed with less computation.
    Circuit World 08/2007; 33(3):9-20. · 0.60 Impact Factor
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    ABSTRACT: Multi-layered printed circuit boards (PCBs) contain a multi-layered structure that is suitable for high-speed and high-frequency applications. Hence, they are used extensively in electronic packaging assemblies for high-density applications. However, numerous composite parts and complex material properties of multi-layer PCBs complicate the reliability simulation of PCB model. This paper deals with a finite element analysis intended to describe numerically the behavior of multi-layered multi-materials PCB model (combination of metallic and composite plies) in the drop-impact performance. Through the comparison of physical drop test results, the fully multi-layered model illustrates higher accuracy if compared with that of the traditional simplified isotropic model and orthotropic model. The effects of material properties for the multi-layer PCB under drop-impact shock have also been investigated.
    Microelectronics Reliability 02/2006; · 1.21 Impact Factor
  • Yuqi Wang, K. H. Low
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    ABSTRACT: Dynamic loading often plays a critical role in the functional performance and mechanical reliability of packaged components and devices. The prediction of the drop-impact response of the structural element of electronic components becomes one of the important concerns in product design. The interaction response between the cushion system and its packed products is also focused. In the analysis of these dynamic responses, the cushion system is often simplified as a linear and un-damped system. However, in reality, the stiffness of the cushion system is nonlinear and the damping effect cannot be ignored in the drop-impact process. Therefore, an algorithm for the nonlinear response analysis of viscous damping models is presented in this study.The whole cushion buffer is first represented by a multi-degree-of-freedom system in this model. Nonlinear characteristics and viscous damping are included in the system. The developed mathematical model provides a practical and reliable method to predict the dynamic behaviors of nonlinear systems with viscous damping. The effects of nonlinear characteristics and viscous damping in the protection of packaged products are both discussed in this paper. The discussion provides a useful insight that both nonlinear characteristics and viscous damping can reduce “rigid impact” to certain level.
    Computers & Structures 07/2005; 83(19):1584-1594. · 2.18 Impact Factor
  • Yuqi Wang, K. H. Low
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    ABSTRACT: The ability to predict crashworthiness is helpful for the cushion design. This is to minimize the impact loading on packaged products, such as drop impact loading occurring during shipment or transportation. In addition, the nonlinear characteristic of cushion system would affect the crashworthiness of the packaged goods. Therefore, an accurate analysis for the nonlinear cushion system is crucial in reliability design. However if nonlinear analysis is performed, a large computation load is required for numerical approaches; on the other hand, there is a need to include higher transcendent functions within the analytical approaches. In this paper, an analytical linearization method is applied to obtain quantitative solution in the nonlinear analysis. This method is not a numerical method, meanwhile, no high transcendent functions are considered. Therefore, the crashworthiness for nonlinear drop-impact systems can be quickly evaluated. In practical application, this method also shows good efficiency and good agreement with the experimental results.
    ASME 2005 International Mechanical Engineering Congress and Exposition; 01/2005
  • Yuqi Wang, K. H. Low, K. H. Hoon
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    ABSTRACT: The materials used in the field of printed circuit boards (PCBs) are becoming increasingly complex as they are common to make use of numerous combination of metallic and composite plies in micro level. The potential for utilization is generally verified through the numerical simulation, especially for the multilayer PCBs with high electronic density. This paper presents a finite element model, bi-phase multilayer model, intended to numerically describe the behavior of multilayer multimaterial PCBs. Two parts for the finite element model are considered: one is elastic-plastic damaging model that is for the metallic ply; another one is bi-phase model that is for glass-fiber/epoxy-resin composite ply with fiber/matrix structure. These two plies are the basic components of multilayer PCBs. Finally, the numerical model is validated by the comparison with experimental results. The damage modeling is also discussed in the present study.
    ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference; 01/2005
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    ABSTRACT: Various rovers with robust locomotion design have been developed and documented. However, the rover locomotion design with omni-directional mobility has not been addressed commonly. Shrimp suspension system and parallel bogies are employed as robot locomotion. It adapts to the terrain profile passively and it has better climbing capability than other rovers. In this paper, a locomotion study of a wheeled mobile robot combining omni-directional mobility and climbing ability is presented. The models of the kinematics and dynamics of the locomotion are presented and they are essential for torque estimation and motion control. The paper also presents the design principle, kinematics, and motion studies. Experimental testings to verify the developed model are discussed.
    ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference; 01/2005
  • Yuqi Wang, K. H. Low, K. H. Hoon
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    ABSTRACT: The materials used in the field of printed circuit boards are becoming increasingly complex as they are common to make use of numerous combination of metallic and composite plies. The potential for utilization of circuit boards is generally verified through the numerical simulation, especially for the multilayer printed circuit boards with high electronic density. This paper provides a numerical model intended to describe numerically the behavior of multilayer multimaterial circuit boards. Two parts are considered in the developed model: one is elastic-plastic damaging model that is presented to describe the metallic ply in the multilayer circuit boards; another is degenerated bi-phase model that is presented to describe composite ply. With the combination of equivalent laminate (EQLAM) method, the degenerated bi-phase successfully models the woven glass-fiber/epoxy-resin composite ply. These two plies are the basic components of multilayer circuit boards. Meanwhile, with the verification of static tests and dynamic tests, the reliability of presented model is confirmed.
    ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference; 01/2005
  • K.H. Low, Yuqi Wang, K.H. Hoon, W.K. Wai
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    ABSTRACT: In this paper, an effective method using the concept of virtual boundary is incorporated into the drop/impact simulation. Drop/impact-induced damage is one of the most predominant modes of failure electronic devices suffer in their usage. Drop/impact performance testing is usually conducted to investigate and understand the detailed impact behavior and damage mechanism of the product. This assessment can be performed through a computer simulation. The finite element method (FEM) is one of such techniques to achieve solutions within reasonable computational time and cost. However, in the large-scale packaged electronic devices model, the packaging components outside the electronic devices sometime incur too much CPU time in a drop–impact simulation, and thus a long computational time. Especially the cushion buffers that protect the electronic devices usually have very complex shapes and they are often meshed as solid elements by the FEM software. This causes a large demand for CPU time for the model involving the cushion buffers. With the proposed virtual boundary method, the boundary field, which only accounts for about 10% of original CPU time, will replace those external components. Accordingly, the substantial CPU time on those components and elements will be saved, and designers can obtain the simulation results of electronic components in a much shorter time. In this study, the reliability and advantage of the virtual boundary method are illustrated through the analysis of a TV model. The application of the method to an electronic component, a printed circuit board in the TV model, is also briefly discussed.
    Advances in Engineering Software 08/2004; 35(8-9-35):537-551. · 1.42 Impact Factor
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    ABSTRACT: The drop test analysis by using finite element method (FEM) needs effective techniques to achieve solutions within reasonable computational time. Therefore a global-local (GL) model is suggested in this work to reduce the computation time of the whole solution process with a reasonable accuracy. The proposed GL method is used to analyze a large-scale finite element TV model with complex and detailed components. The possibility of partial breaking of TV undergoing impact-contact condition is discussed. It also shows that the impact problem of TV finite element model with complex and a large number of detailed components in impact problem can be solved with an existing software within reasonable computational time. The Hertz's theory is also used in this work to reduce the impact force of the original model by changing certain properties. The results obtained through different parameters are presented and discussed.
    Advances in Engineering Software 03/2004; 35(3):179-190. · 1.42 Impact Factor
  • K.H. Low, Yuqi Wang, K.H. Hoon, W.K. Wai
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    ABSTRACT: Modeling and simulation of printed circuit boards (PCB) during drop test are often performed for electronic device assemblies. As sensitive components in electronic devices, components on the PCB are easily damaged during a drop-impact process. While different PCB positions in the electronic devices can cause different stress and strain on the board, these impact behaviors can also make a difference to the force along the solders that connect the chips to the PCB. Through an existing FEA software tool, we can find an optimal position of the PCB on the electronic device to improve product quality. To illustrate the proposed method, the drop simulation of a PCB specimen mounted on a packaged TV product was performed. Dynamic modeling and simulation of drop test was established and presented. The position of the PCB was optimized through the proposed virtual boundary method. With the method, three optimization models were considered, and the designs were proven to successful by comparing the stress and deflection of concerned points on the PCB. It is also found that the method can quickly determine several PCB optimal positions in electronic devices directly by the magnitudes of the deflection and stress.
    Electronics Packaging Technology, 2003 5th Conference (EPTC 2003); 01/2004

Publication Stats

20 Citations
7.43 Total Impact Points

Institutions

  • 2005–2008
    • Nanyang Technological University
      • • School of Mechanical and Aerospace Engineering (MAE)
      • • School of Mechanical and Production Engineering
      Singapore, Singapore
    • Nanyang Normal University
      Nan-yang-shih, Henan Sheng, China