S.L. Chan

A dynamic decision support system to predict the value of customer for new product development

In recent years, firms have focused on how to enter markets and meet customer requirements by improving product attributes and processes to boost their market share and profits. Consequently, market-driven product design and development has become a popular topic in the literature. However, past research neither covers all of the major influencing factors that together drive customers to make purchase decisions, nor connects these various influencing factors to customer purchasing behavior. Past studies further fail to take the time value of money and customer value into consideration. This study proposes a decision support system to (a) predict customer purchasing behavior given certain product, customer, and marketing influencing factors, and (b) estimate the net customer lifetime value from customer purchasing behavior toward a specific product. This will not only enable decision-makers to compare alternatives and select competitive products to launch on the market, but will also improve the understanding of customer behavior toward particular products for the formulation of effective marketing strategies that increase customer loyalty and generate greater profits in the long term. Decision-makers can also make use of the system to build up confidence in new product development in terms of idea generation and product improvement. The application of the proposed system is illustrated and confirmed to be sensible and convincing through a case study.

Column buckling of structural bamboo

Abstract Bamboo scaffolding is widely used in construction in the South East Asia, in particular, the Southern China and Hong Kong for many decades. However, bamboo scaffolds are generally erected by scaffolding practitioners based on their intuition and experiences without any structural design. In general, column buckling is considered to be one of the critical modes of failure in bamboo scaffolds, often leading to their overall collapse. This paper presents a research and development project for structural bamboo where the column buckling behaviour of two structural bamboo species, namely Bambusa pervariabilis (or Kao Jue) and Phyllostachys pubescens (or Mao Jue) were investigated. A total of 72 column buckling tests with bamboo culms of typical dimensions and properties were executed to study the column buckling behaviour of structural bamboo. Furthermore, a limit state design method against column buckling of structural bamboo based on modified slenderness was established and carefully calibrated against test data. It is shown that for Kao Jue, the average model factors of the proposed design method are 1.63 and 1.86 for natural and wet conditions, respectively. Similarly, the average model factors of the proposed design method for Mao Jue are 1.48 and 1.67 for natural and wet conditions, respectively. Consequently, the proposed design method is shown to be adequate. With the availability of design data on the dimensions and the mechanical properties of structural bamboo together with the proposed column buckling design rule, structural engineers are encouraged to take the advantage offered by bamboo to build light and strong bamboo structures to achieve enhanced economy and buildability.

High clearance scaffold systems during construction —I. Structural modelling and modes of failure

The highest risk to structures during their lifetime is generally during the construction phase. This is evidenced by the fact that most structural failures occur during the placement of fresh concrete in construction rather than after the structure is completed and is in service. A scaffold support system, often a combination of modular steel scaffolds and wooden shores, is typically used for temporary support during the construction of high-clearance concrete buildings in Asia. Such temporary support systems are often used because they are convenient, versatile and relatively inexpensive. No guidelines exist, however, for the design and use of these temporary structures during construction. This paper focuses on the development of a computer model based on actual construction practices which is then used to provide a description of likely causes of scaffold support system collapse during construction. An examination of the effect of combining wooden shores with modular steel scaffolds on the performance of temporary support structures then follows.

Out-of-plane advanced analysis of steel structures

Abstract Attempts to extend practical advanced analyses of the in-plane behaviour of 2-D steel frames under in-plane loading to out-of-plane behaviour have been largely unsuccessful because of difficulties in modeling the effects of yielded zones, load heights, interactions between twist and axial force and moments, and end warping restraints. Advanced analyses need to be able to account for the influences of moment and axial force distributions, load heights, and end restraints on elastic and inelastic lateral buckling, and to be consistent with the code formulations of beam and column out-of-plane strengths. This paper reviews extensions of methods of advanced analysis beyond those for the in-plane behaviour of 2-D frames for which local buckling is prevented towards the behaviour of 3-D frames under general loading. An early step towards this goal is the development of an advanced analysis for the out-of-plane behaviour of 2-D frames under in-plane loading. It has been proposed that this should be simplified by first carrying out an in-plane analysis using one of the presently available plastic hinge methods, and then by using a practical advanced analysis of the out-of-plane behaviour which is based on an inelastic lateral buckling analysis which includes allowances for residual stresses and initial crookednesses and twists. This paper discusses some of the difficulties to be overcome in the development of such a method, so that future attempts to develop advanced analyses for the lateral buckling of 2-D frames for which local buckling is prevented can systematically assess these difficulties and develop methods of overcoming them. Suggestions are also made for testing and benchmarking these analyses.

High clearance scaffold systems during construction - II. Structural analysis and development of design guidelines

A simplified structural analysis procedure for high-clearance scaffold systems based on a ‘set’ concept is presented. The validity of this simplified procedure is confirmed by comparing the results with the more refined computer model developed in part one of this paper (Engng Struct. 1996, 18, 247–257). The effect of bamboo cross-braces on increasing the stiffness of the scaffold system is also investigated. On the basis of the analysis results, a simplified procedure for estimating the critical loads for scaffold systems and some recommendations for practical design are presented. Both the simplified analysis procedure and the recommended guidelines have the potential for use by engineers in the actual design of scaffold systems during construction.

Modeling supply chain performance and stability

Purpose – The purpose of this paper is to propose an integrated approach to modeling and measuring supply chain performance and stability using system dynamics (SD) and the autoregressive integrated moving average (ARIMA).Design/methodology/approach – SD and ARIMA models were developed, respectively, for modeling and measuring supply chain performance and for further analyzing and projecting supply chain stability for long‐term management. A case study from a typical semiconductor equipment manufacturing company is used to illustrate and validate the proposed method.Findings – Effectiveness and efficiency, with six corresponding indicators (product reliability, employee fulfillment, customer fulfillment, on‐time delivery, profit growth, and working efficiency), were found to be the most significant factors in the performance of the supply chain. The results of the combined model provide evidence that supply chain performance of the case company is up to standard (average OPIN=0.64) and is considered stabl...

Numerical analysis of composite frames with partial shear–stud interaction by one element per member

Abstract A numerical plastic-layer procedure based on a simplified finite element method is proposed for the analysis of composite flooring frames in a serviceability deflection limit state which allows for the spread of concrete cracks along the length of a beam. It allows for a very important effect of partial interaction between the steel beam and the concrete slab. In the proposed method, discrete shear connectors are assumed to be continuous along the beam–slab interface. Thus, the entire composite beam is modelled by a single element with a hybrid mixed-shape function for the transverse deformation which is superior to the currently used polynomial displacement functions. The application of the proposed method is demonstrated through a number of worked examples. When using the proposed numerical integration technique and associated mixed-formed element for modelling of material cracking and yielding, a single element per member is already adequate for large deflection analysis of composite frames with arbitrarily distributed concrete cracks.

Transient response of moment-resistant steel frames with flexible and hysteretic joints

Abstract A robust method for geometrically nonlinear analysis of flexibly connected steel frames with hysteretic connection subjected to dynamic loads is presented. The proposed method revises the available monotonic moment vs rotation curves for typical connections to include the hysteretic loop characteristics for dynamic analysis of semi-rigid frames. Using this simple and efficient computer method of analysis, the influence of the nonlinear hysteretic loop for connection over the structural response in a large deflection range of a steel frame is studied. The extent of such an effect is quantified. It was found that neither the rigid nor the linear semi-rigid connection can predict accurately the response of moment frames where damping at connections is significant. Also, the use of several common connection models will generate similar load-deflection curves, indicating that the choice of these models may not be essential.

Stability analysis of semirigid steel scaffolding

Abstract Skeletal structures with members under high axial loads, defined as brittle structures, are widely used in practice. Structures in this category include space frames, transmission towers, and steel and bamboo scaffolding. The collapse of this type of structure is considerably more frequent than that of the conventional beam-column type of steel building. The structure may fail by a series of members buckling which may be initiated by a single member failure or, by global snap-through instability. In both cases, the connection stiffness plays an important role in affecting the buckling capacity of the structure. The linear analysis of this type of brittle structure is basically not different from the conventional analysis of the beam-column type of structure. However, in nonlinear analysis, their methods of analysis differ since the former requires a careful consideration of the second-order effect due to axial load. This paper details the method specially designed for elastic buckling analysis of scaffolding systems where failure is controlled by instability. Theinfluence of the connection stiffness is included in the analysis by the concept of effective length. The application of the proposed method is demonstrated in a number of worked examples.

Non-linear behavior and design of steel structures

Abstract Frames are possibly the most common forms of man-made engineering structures. They are formed by joining one-dimensional members together. Since the early work of Euler, engineers started to realize that the strength of a member under compression does not only depend on the material yield stress, but also on the Young’s modulus of elasticity. The introduction of steel material and other metals makes the consideration more important because of their relatively slender dimensions. From the vision of the current computer age, this paper is addressed to a review and summary of the work conducted on the non-linear analysis and design of steel frames in the past few decades.