Synthetic double sampling np control chart for attributes

The quality of a product, based on the number of non-conforming items can be controlled using the np chart. This paper proposes a synthetic double sampling (DS) np chart which comprises two sub-charts, i.e. the DS np and conforming run length (CRL) sub-charts. For the zero-state case, the synthetic DS np chart surpasses its standard counterpart, i.e. the synthetic np and the basic DS np chart, and other np type charts like the standard np, combined synthetic and np (Syn-np), variable sample size (VSS) np, exponentially weighted moving average (EWMA) np and cumulative sum (CUSUM) np charts, for detecting increases in the fraction of non-conforming items p, for most shift sizes. The synthetic DS np chart also performs reasonably well in the steady-state case in comparison with other charts mentioned above. Thus, among the competing charts, the synthetic DS np chart stands out as one of the best charts.     

如切如磋,如琢如磨——与医院业主在设计理念上的互动

本文侧重对医院设计前期业主和建筑师共同关注的重要问题进行分类探讨,同时对建筑师应该发挥的作用进行探讨与分析,概括与业主之间的五种互动关系,并结合具体的实例进行说明、论证,以探索在医疗建筑设计中实现设计价值的一些方法,以及如何通过这些方法达到各方共赢的结果。     

一个乡村旅游地的前世今生——绍兴大香林风景区规划设计札记

以复杂性科学为指导,从场地条件解析与景区结构的生成、游赏功能解析与景观单元的构建、历史文化解析与景观意向的升华等三个方面阐述了绍兴大香林风景区的规划设计过程.通过分析建设过程中的得与失,总结了复杂的整合设计策略与"自然是基础,人为目标"的规划设计理想.     

New method for graded mesh generation of all hexahedral finite elements

Mapping method is widely applied by most of commercial mesh generators because of its efficiency, mesh quality. One of the obstacles to apply the mapping method and generate a graded all hexahedral mesh of high quality in an arbitrarily three-dimensional domain is the generation of hexahedral parent elements on a super-element that allows for gradations in three co-ordinate directions. This paper presents a pattern module’s method to generate the graded mesh of all hexahedral elements in a cube and thus improves the mapping method. The method requires few calculations.     

Characterization of the contact between a punch and a half-infinite substrate in a fretting situation

This paper analyzes the behavior of a mechanical system formed by a flat punch with square edges at 90 over a half-infinite substrate made of the same material under normal reversible constant and tangential loads, typical of a fretting situation. Based on previous studies of the behavior of such a system, both static and cyclic behavior are analyzed. The analysis is carried out using both analytical and numerical solutions, the latter being obtained with finite and/or boundary element codes. The kinematic behavior of the contact zone is studied (slipping, separation, or adherence), as well as the stress state of the substrate in the area surrounding the edges of the punch. The very same analyses have been made of a system equal to the latter but replacing the contact by continuity. The comparison of the solutions of the two systems gives the validity range of different continuous models, easier to use in representing the behavior of the punch–substrate system.     

Reduced dependence on loading parameters in almost conforming contacts

In cases of completely conforming frictionless contact, the contact area generally either decreases or stays the same under load, in which case the extent of the contact area is subsequently independent of load and the stress and displacement fields vary linearly with the loading parameter. Dundurs and Stippes describe such cases as receding contact problems. Here, we demonstrate that similar results apply in the presence of Coulomb friction, in which case the extent of the stick and slip zones and the local direction of sliding are independent of load. We also show that if there is a small initial gap or interference throughout the potential contact area, the extent of the contact area and the stress and displacement fields will approach those of the corresponding receding contact problem as the applied load is increased. If the interface conditions permit adhesion between the contacting surfaces, the extent of the adhesion zone shrinks to zero as the load increases without limit. Progress of the contact configuration towards the limit is governed solely by a dimensionless load factor involving the ratio between the applied load and the initial clearance or interference. This permits results for a variety of initial geometries (due to tolerance variations) to be obtained from a set of finite element results for a single case. Some of these characteristics are demonstrated using a finite element solution of a connecting rod/bushing/gudgeon pin contact. Other interesting applications are those with complex geometries, ranging from biomechanics, as in prostheses, to the design of multiple fasteners.     

A Note on the Lower-Sided Synthetic Chart for Exponentials

The synthetic control chart for exponential data is discussed and an expression is derived for its average run length, as well as its design parameters. The synthetic control chart for exponentials is shown analytically to be a two-in-a-row rule. This chart is compared with the Shewhart chart for individuals and with the worst-case, lower-sided exponential EWMA and CUSUM charts. While the synthetic control chart for exponentials outperforms the Shewhart chart for individuals, the EWMA and CUSUM charts are shown to be far superior in detecting decreases in the exponential mean.     

A generalized Conforming Run Length control chart for monitoring the mean of a variable

The attribute Conforming Run Length (CRL) control chart has attracted increasing research interests in Statistical Process Control (SPC). It decides the process status based on the interval or distance between two nonconforming units. This article proposes a Generalized CRL chart (namely GCRL chart) for monitoring the mean of a measurable quality characteristic x under 100% inspection. To run a GCRL chart, each unit will be classified as a passing or nonpassing unit depending on whether the sample value of x falls within or beyond a pair of lower and upper inspection limits LIL and UIL. When a nonpassing unit is detected, the GCRL chart checks the distance between the current and last nonpassing units in order to determine the process status (in control or out of control). The inspection limits LIL and UIL are determined by an optimization design. The GCRL chart not only solves a dead-corner problem suffered by the conventional CRL chart, but also considerably outperforms the latter for detecting mean shifts. The most interesting finding is that the attribute GCRL chart excels the variable X chart to a significant degree in SPC for variables. It suggests that the simple attribute chart may replace the variable chart in some SPC applications. The design of the GCRL chart has to be carried out by a computer program, but the design can be completed almost in no time in a personal computer.     

用简单高效的矩形广义协调元分析薄板的振动

本文介绍一种在薄板振动分析中很简单,而且很实用的广义协调矩形元,将其应用于薄板固有振动分析中,求解前几阶的固有频率。文中算例表明,该单元简易,程序通用,且精度高。同时,它还可以与平面应力单元组合,构成平板型壳单元,用以分析某些壳体(如柱壳、折板等)的振动,同样简单实用。