K. WISNIEWSKI and B.A. SCHREFLER
The stress recovery procedures discussed in the present paper refer to a multi‐layered element of assembled Timoshenko beam elements. Directly calculated stresses for a…
Abstract
The stress recovery procedures discussed in the present paper refer to a multi‐layered element of assembled Timoshenko beam elements. Directly calculated stresses for a multi‐layered beam model strongly depend on properties of the approximation functions, and are unrealistic. Thus, an enhanced procedure which circumvents the limitations of the interface variables model, and hierarchical model is proposed. Each material layer of the beam element is covered by one quadrilateral 9‐node element, providing a parabolic approximation of displacements. The stresses are evaluated using 2 × 2 Gauss points, projected to corner nodes, and smoothed within material layers. Numerical calculations show very good accordance of stresses yielded by this procedure with 2D results.
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The purpose of this paper is to estimate the size of the population of people with Down’s syndrome in Scotland in order to provide a basis for estimating likely numbers of people…
Abstract
Purpose
The purpose of this paper is to estimate the size of the population of people with Down’s syndrome in Scotland in order to provide a basis for estimating likely numbers of people with dementia in Down’s syndrome at a range of ages.
Design/methodology/approach
Recorded data were requested from all general practitioner (GP) services in Scotland on people with an identified READ code denoting Down’s syndrome. A statistical weighting model was then applied to account for non-response bias.
Findings
There were 3,261 people with Down’s syndrome estimated by the application of a statistical weighting model. Of these, 1,118 people (34 percent) were aged between 40 and 59. This age banding includes the age groups reported as having the highest incidence of early onset dementia in Down’s syndrome.
Research limitations/implications
It is not possible to apply a benchmark to the percentage of observed data which gives an indication of how accurate the estimates produced are. Rather, the quality of the estimates depends on the response rate itself and the extent to which response is correlated with the outcome variable. In short, the quality of the final weighted estimates depends on the extent to which the biasing effect is mitigated by the weighting. As a result, a different response rate to this survey would have resulted in variations in the weighting model and therefore provided a different set of estimates.
Social implications
Adults with Down’s syndrome have an elevated risk of developing dementia significantly earlier than the general population and require specific age appropriate supports and services to meet their needs both pre and post-diagnosis. The reality of this is currently not fully realized in either standard practice or national policy concerning the issue.
Originality/value
This is the first set of data collected from GP services in Scotland to examine this issue and attempt to identify the population of people with Down’s syndrome in Scotland as a whole.
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Krzysztof Wiśniewski and Robert L. Taylor
Numerical aspects of initial stability analysis of a cylindrical shell of non‐constant parameters along the generator and under non‐symmetrical loads are considered. A variational…
Abstract
Numerical aspects of initial stability analysis of a cylindrical shell of non‐constant parameters along the generator and under non‐symmetrical loads are considered. A variational approach based on Sanders' and Donnell's non‐linear equations of thin, elastic shells is applied. The problem is decomposed to determine: the stability vectors in the axial direction in the first step, and the critical load and the stability vector in the circumferential direction in the second step. The discretization is based on finite Fourier representations and the finite difference method. To find the approximate stability vector in the axial direction an auxiliary problem for axisymmetric loads is solved. The error of the method is defined and the effectiveness of the method is estimated. The decomposition leads to small and fast algorithms suitable for personal computers. Shells with constant and stepped thicknesses under wind loads are calculated as examples. Tested algorithms show considerable effectiveness and good accuracy of results.
James T Gayton and Justin Lawrence Lapp
Continuous fiber-reinforced thermoplastic composites are a class of materials highly valuable for structural applications and modeling of heat transfer within them is critical to…
Abstract
Purpose
Continuous fiber-reinforced thermoplastic composites are a class of materials highly valuable for structural applications and modeling of heat transfer within them is critical to the design of their processing methods. However, the fiber reinforcement leads to highly anisotropic thermal conduction. Among a variety of methods to account for anisotropic thermal conductivity, continuum models with effective media approximation thermal conductivity are computationally efficient and require minimal data to begin modeling a specific composite material. The purpose of this study is to evalute the utility of these models.
Design/methodology/approach
In this work, six potential effective media approximation models are evaluated against experimental heating data. Thick (>25 mm) glass fiber-reinforced polyethylene terephthalate glycol (PET-G) specimens with 40% fiber volume fraction were heated with embedded resistance heating to produce validation and testing data sets. A two-dimensional finite-difference solver was implemented using each of the six effective media approximation models. The accuracy of each model is compared.
Findings
The model developed by Cheng and Vachon was found to predict the experimental results most accurately. Fit statistics were similar in the testing and validation data sets. This model is recommended for simulation of transient heating in continuous fiber-reinforced thermoplastic composites with low-to-moderate fiber volume fractions.
Originality/value
There are a wide variety of mathematical models for effective media approximation thermal conductivity, though very few have been applied to continuous fiber-reinforced thermoplastic composites. This work shows that the simplest methods based on rules of mixtures are well outperformed by more modern and complex models, and should be incorporated for accurate prediction of heating during thermal processing of fiber-reinforced thermoplastic composites.
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During the last decade, we have witnessed a steady stream of research focusing on the nature of competition between different brand tiers (e.g. high‐priced brands vs low‐priced…
Abstract
During the last decade, we have witnessed a steady stream of research focusing on the nature of competition between different brand tiers (e.g. high‐priced brands vs low‐priced brands, national brands vs store label brands). Several interesting research findings have been reported in the literature. This article highlights the methodological issues associated with the research on price‐tier competition and delineates the connection between methodological issues and managerial implications of the substantive research findings.
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The nature of competition between different tiers (e.g. high‐tier vs low‐tier brands) has become an important research domain for academic researchers and marketing managers…
Abstract
The nature of competition between different tiers (e.g. high‐tier vs low‐tier brands) has become an important research domain for academic researchers and marketing managers. Although research on inter‐tier competition is growing at an increasing rate, there has not been a comprehensive attempt to summarize the research in this stream. The objective of this article is to synthesize the research on inter‐tier competition, extract the key findings, discuss managerial implications, and offer future research directions.
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This paper aims to offer an alternative explanation for asymmetric quality‐tier competition.
Abstract
Purpose
This paper aims to offer an alternative explanation for asymmetric quality‐tier competition.
Design/methodology/approach
A conceptual framework based on quality‐price tradeoff is used in the study to derive research hypotheses and scanner panel data are used for empirical validation.
Findings
The paper finds that the concept of tradeoffs offers a simple explanation for asymmetric competition in favor of high quality brands; as the quality differential increases, asymmetry increases; as the price differential increases, the asymmetry decreases.
Practical implications
The framework and findings can inform pricing strategies for brands in different quality tiers.
Originality/value
The paper offers an alternative explanation for asymmetric competition.
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Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
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This paper aims to describe the formulation of a displacement-based triangular membrane finite element with true drilling rotational degree of freedom (DOF).
Abstract
Purpose
This paper aims to describe the formulation of a displacement-based triangular membrane finite element with true drilling rotational degree of freedom (DOF).
Design/methodology/approach
The presented formulation incorporates the true drilling rotation provided by continuum mechanics into the displacement field by way of using the polynomial interpolation. Unlike the linked interpolation, that uses a geometric transformation between displacement and vertex rotations, in this work, the interpolation of the displacement field in terms of nodal drilling rotations is obtained following an unusual approach that does not imply any presumed geometric transformation.
Findings
New relationship linking the mid-side normal displacement to corner node drilling rotations is derived. The resulting new element with true drilling rotation is compatible and does not include any problem-dependent parameter that may influence the results. The spurious zero-energy mode is stabilized in a careful way that preserves the true drilling rotational degrees of freedom (DOFs).
Originality/value
Several works dealing with membrane elements with vertex rotational DOFs have been published with improved convergence rate, however, owing to the need for incorporating rotations in the finite element meshes involving solids, shells and beam elements, having finite elements with true drilling rotational DOFs is more appreciated.
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This article aims to extend the price‐quality trade‐off framework to derive new results for differential pricing strategies for brands in different brand tiers. The results are…
Abstract
Purpose
This article aims to extend the price‐quality trade‐off framework to derive new results for differential pricing strategies for brands in different brand tiers. The results are demonstrated for different market configurations.
Design/methodology/approach
A conceptual framework based on the quality‐price trade‐off from existing literature is used to analytically derive research hypotheses regarding pricing strategies. The results are demonstrated empirically by extending previously published results.
Findings
The study reveals that optimal pricing strategies are dependent on the tier to which the brands belong. Promotional pricing is better for high‐tier brands, while everyday low price is better for low‐tier brands. Similarly, deep and infrequent price promotions are better for high‐tier brands, while shallow and frequent promotions are better for low‐tier brands.
Practical implications
The findings offer some important implications of the brand‐tier competition framework for determining optimal pricing strategies and can inform pricing strategies for brands in different tiers.
Originality/value
Asymmetric inter‐tier competition is demonstrated for different market configurations, and the framework is used to derive optimal pricing strategy implications for brands in different tiers.