Development of smart transducer with embedded sensor for automatic process control of ultrasonic wire bonding

Or, Siu Wing,Chan, Helen Lai Wa,Liu, Peter Chou Kee Techno-Press 2005 Smart Structures and Systems, An International Jou Vol.1 No.1

A ring-shaped lead zirconate titanate (PZT) piezoceramic sensor has been integrated with the Langevin-type piezoceramic driver of an ultrasonic wire-bonding transducer to form a smart transducer for in-situ measurement of three essential bonding parameters: namely, impact force, ultrasonic amplitude and bond time. This sensor has an inner diameter, an outer diameter and a thickness of 12.7 mm, 5.1 mm and 0.6 mm, respectively. It has a specifically designed electrode pattern on the two major surfaces perpendicular to its thickness along which polarization is induced. The process-test results have indicated that the sensor not only is sensitive to excessive impact forces exerted on the devices to be bonded but also can track changes in the ultrasonic amplitude proficiently during bonding. Good correlation between the sensor outputs and the bond quality has been established. This smart transducer has good potential to be used in automatic process-control systems for ultrasonic wire bonding.

Design optimization of vibration isolation system through minimization of vibration power flow

Shilin Xie,Siu Wing Or,Helen Lai Wa Chan,Ping Kong Choy,Peter Chou Kee Liu 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

Cross-sectional analysis of arbitrary sections allowing for residual stresses

Tian-Ji Li,Siu-Lai Chan,Si-Wei Liu 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.4

The method of cross-section analysis for different sections in a structural frame has been widely investigated since the 1960s for determination of sectional capacities of beam-columns. Many handcalculated equations and design graphs were proposed for the specific shape and type of sections in precomputer age decades ago. In design of many practical sections, these equations may be uneconomical and inapplicable for sections with irregular shapes, leading to the high construction cost or inadequate safety. This paper not only proposes a versatile numerical procedure for sectional analysis of beam-columns, but also suggests a method to account for residual stress and geometric imperfections separately and the approach is applied to design of high strength steels requiring axial force-moment interaction for advanced analysis or direct analysis. A cross-section analysis technique that provides interaction curves of arbitrary welded sections with consideration of the effects of residual stress by meshing the entire section into small triangular fibers is formulated. In this study, two doubly symmetric sections (box-section and H-section) fabricated by high-strength steel is utilized to validate the accuracy and efficiency of the proposed method against a hand-calculation procedure. The effects of residual stress are mostly not considered explicitly in previous works and they are considered in an explicit manner in this paper which further discusses the basis of the yield surface theory for design of structures made of high strength steels.

Design optimization of vibration isolation system through minimization of vibration power flow

Xie, Shilin,Or, Siu Wing,Chan, Helen Lai Wa,Choy, Ping Kong,Liu, Peter Chou Kee Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

Sequential pattern load modeling and warning-system plan in modular falsework

Peng, Jui-Lin,Wu, Cheng-Lung,Chan, Siu-Lai Techno-Press 2003 Structural Engineering and Mechanics, An Int'l Jou Vol.16 No.4

This paper investigates the structural behavior of modular falsework system under sequential pattern loads. Based on the studies of 25 construction sites, the pattern load sequence modeling is defined as models R (rectangle), L and U. The study focuses on the system critical loads, regions of largest reaction forces, discrepancy between the pattern load and the uniform load, and the warning-system plan. The analysis results show that the critical loads of modular falsework systems with sequential pattern loads are very close to those with the uniform load used in design. The regions of largest reaction forces are smaller than those calculated by the uniform load. However, the regions of largest reaction forces of three models under sequential pattern loads can be considered as the crucial positions of warning-system based on the measured index of loading. The positions of the sensors for the warning-system for these three different models are not identical.

Experimental Study on Load-Bearing Capacities of Frame-Type Scaff olds Used in Precast Construction

Jui-LinPeng,Pao-Li Wang,Siu-Lai Chan,Po-Kai Wu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.2

In precast construction, because the precast beams are broader and the frame-type steel scaffolds need to bear more weight, such as that of the precast slabs and precast beams, the dimensions and load-bearing capacities of the frame-type steel scaffolds are different from those of traditional door-type steel scaffolds. The results of this study show that based on the load-bearing capacities of the five different combined setups of frame-type steel scaffolds used in this study, the horizontal members of the square-type and rectangle-type steel scaffolds are able to enhance the load-bearing capacities of the combined setups of the frame-type steel scaffolds. Therefore, when adopting combined setups of frame-type steel scaffolds, it is advisable to refrain from using only door-type steel scaffolds on construction sites. The ability of jack bases to enhance the load-bearing capacities of frame-type steel scaffolds is not significant. Under the condition of an eccentric load located at one-third of both the x-axis and y-axis, the load-bearing capacity of the frame-type steel scaffolds reduces to 60% of that when no eccentric load is involved. When a lateral force is applied, the critical load of frame-type steel scaffolds decreases with increasing lateral forces.

Curved-quartic-function elements with end-springs in series for direct analysis of steel frames

Si-Wei Liu,Jake Lok Yan Chan,Rui Bai,Siu-Lai Chan 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.5

A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is explicitly integrated into the element formulation, and, therefore, the <i>P</i>-<i>δ</i> effect can be directly captured in the analysis. The series of zero-length springs are placed at the element ends to model the effects of semi-rigid joints and material yielding. One-element-per-member model is adopted for design bringing considerable savings in computer expense. The incremental secant stiffness method allowing for large deflections is used to describe the kinematic motion. Finally, several problems are studied in this paper for examining and validating the accuracy of the present formulations. The proposed element is believed to make DA simpler to use than existing elements, which is essential for its successful and widespread adoption by engineers.

A force-based element for direct analysis using stress-resultant plasticity model

Zuo-Lei Du,Yao-Peng Liu,Siu-Lai Chan 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.2

The plastic hinge method and the plastic zone method are extensively adopted in displacement-based elements and force-based elements respectively for second-order inelastic analysis. The former enhances the computational efficiency with relatively less accurate results while the latter precisely predicts the structural behavior but generally requires more computer time. The displacement-based elements receive criticism mainly on plasticity dominated problems not only in accuracy but also in longer computer time to redistribute the forces due to formation of plastic hinges. The multi-element-per-member model relieves this problem to some extent but will induce a new problem in modeling of member initial imperfections required in design codes for direct analysis. On the contrary, a force-based element with several integration points is sufficient for material yielding. However, use of more integration points or elements associated with fiber section reduces computational efficiency. In this paper, a new force-based element equipped with stress-resultant plasticity model with minimal computational cost is proposed for second-order inelastic analysis. This element is able to take the member initial bowing into account such that one-element-per-member model is adequate and complied with the codified requirements of direct analysis. This innovative solution is new and practical for routine design. Finally, several examples demonstrate the validity and accuracy of the proposed method.

Divergence-free algorithms for moment-thrust-curvature analysis of arbitrary sections

Liang Chen,Si-Wei Liu,Siu-Lai Chan 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.5

Moment-thrust-curvatures (M-P-Φ curves) are fundamental quantities for detailed descriptions of basic properties such as stiffness and strength of a section under axial loads required for accurate computation of the deformations of reinforced concrete or composite columns. Currently, the finite-element-based methods adopting small fibers for analyzing a section are commonly used for generating the M-P-Φ curves and they require large amounts of computational time and effort. Further, the conventional numerical procedure using the force-control method might encounter divergence problems under high compression or tension. Therefore, this paper proposes a divergence-free approach, combining the use of the displacement-control and the Quasi-Newton scheme in the incremental-iterative procedure, for generating the M-P-Φ curves of arbitrary sections. An efficient method for computing the strength from concrete components is employed, where the stress integration is executed by layerbased algorithms. For easy modeling of residual stress, cross sections of structural steel components are meshed into fibers for strength resultants. The numerical procedure is elaborated in detail with flowcharts. Finally, extensive validating examples from previously published research are given for verifying the accuracy of the proposed method.

Study on stability and design guidelines for the combined system of scaffolds and shores

Jui-Lin Peng,Chung-Sheng Wang,Shu-Hong Wang,Siu-Lai Chan 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.3

Since the scaffold is composed of modular members, the total height of multi-story scaffolds does not often meet with the headroom of construction buildings. At this time, other supporting members need to be set up on the top of scaffolds. However, the mechanical behaviors of the combined system of scaffolds and other supporting members have seldom been discussed. This study explores the stability of the combined system of scaffolds and shores. The loading tests conducted in the laboratory show that the critical load of the combined system of two-story scaffolds and wooden shores is about half that of the three-story scaffold system with the same height. In the failure of both the “scaffold system” and the “combined system of scaffolds and shores’ after loading, the deformation mainly occurs in the in-plane direction of the scaffold. The outdoor loading test shows that no failure occurs on any members when the combined system fails. Instead, the whole system buckles and then collapses. In addition, the top formwork of the combined system can achieve the effect of lateral support reinforcement with small lateral support forces in the outdoor loading test. This study proposes the preliminary design guidelines for the scaffolding structural design.