bluuebunny/crossref_metadata_2025 huggingface dataset:
Criterion-Related Validity of Selected Achievement Measures in the Prediction of a Passing or Failing Criterion on the National Council Licensure Examination (NCLEX) for Nursing Students in a Two-Year Associate Degree Program
Authors: Drake Carolyn C. , Michael William B.
Published: March 2007

For a sample of nearly 350 nursing students in a 2-year associate degree program, estimates of the predictive validity coefficients in relation to a criterion of passing or failing the National Council Licensure Examination were found for (a) grades earned in each of 18 courses (eight nursing theory courses, six nursing laboratory courses, and four biology-related courses) as well as in composites of nursing theory and nursing laboratory courses, and (b) grade point averages received prior to admission to the program and in the community college itself. It was concluded that the most valid predictor was the grade point average earned in a composite of eight theory or didactic courses in nursing. Addition of other predictors to this one composite variable added no statistically significant contribution to validity. A factor analysis revealed a distinct separation in the performance requirements of nursing theory and nursing laboratory courses.
Dimensionality of the Measure of Ingratiatory Behaviors in Organizational Setiyings (MIBOS) Scale
Authors: Kacmar K. Michele , Valle Matthew
Published: March 2007

The present study examined the dimensionality of K. Kumar and M. Beyerlein's Measure of Ingratiatory Behaviors in Organizational Settings (MIBOS) scale, which is composed of four subscales: (a) Other Enhancement, (b) Opinion Conformity, (c) Self-Presentation, and (d) Favor Rendering. Confirmatory factor analysis using LISREL7 on data collected from 203 state government employees failed to confirm the Kumar and Beyerlein solution. Follow-up analyses using exploratory factor analysis highlight the difficulties involved in arriving at an unequivocal solution that adequately distinguishes scale items. Suggestions are offered to improve the psychometric properties of the MIBOS scale.
Test-Retest of the Myers-Briggs Type Indicator: An Examination of Dominant Functioning
Authors: Salter Daniel W. , Evans Nancy J. , Forney Deanna S.
Published: March 2007

A test-retest study of the Myers-Briggs Type Indicator over 20 months yielded findings similar to those in previous studies of the instrument. However, an additional examination of type dynamics using loglinear analyses indicated that dominant thinking and dominant sensing did not retest as well as did dominant intuition and feeling for this group of 99 master's students. Although the psychometric properties of the instrument could have been a factor, environmental presses appeared to have been the primary influence on these results.
Book Reviews
Authors: Levin Joel R.
Published: March 2007

The impressive 1997 edited volume What If There Were No Significance Tests? is reviewed. The book is applauded for its comprehensive consideration of the pros and cons of statistical hypothesis testing (and alternatives) in psychological and educational research. The highlights of each chapter are summarized along with each contributor's presumed stance on the focal to-test-or-not-to-test question. Also included is the reviewer's personal set of recommendations for transforming statistical hypothesis testing, as it is currently practiced, into an intelligent process that is capable of yielding more informative scientific retums.
TH-SCORE: A Program for Obtaining Ability Estimates Under Different Psychometric Models
Authors: Ferrando Pere J. , Lorenzo Urbano
Published: March 2007

A program for obtaining ability estimates and their standard errors under a variety of psychometric models is documented. The general models considered are (a) classical test theory, (b) item factor analysis for continuous-unlimited and continuous-censored responses, and (c) unidimensional and multidimensional item response theory (IRT) graded response models, which include models for binary items as particular cases. The program can be used to complement the various programs that are available commercially and that enable item parameters to be estimated.
Cultural Tolerance: Measurement and Latent Structure of Attitudes toward the Cultural Practices of Others
Authors: Gasser Michael B. , Tan Rowena N.
Published: March 2007

The goals of the present study were to construct a scale of cultural tolerance, examine the latent structure of this scale, and determine the relationship of the scale to measures of other relevant constructs. The scale was administered to three samples of students from the University of Minnesota. Results based on multidimensional scaling suggested that a two-dimensional structure was the most parsimonious solution. One dimension represented items assessing affect and belief at one pole and items assessing intention to behave at the other pole. The second dimension represented a continuum, with the items related to specific cultures. The components of the scale were shown to correlate differentially with measures of personality constructs.
Transit Map Color Coding and Street Detail
Authors: Garland Howard C. , Haynes John J. , Grubb Grover C.
Published: March 2007

An experiment was performed in which subjects were asked to plan a three-legged trip within a city using one of four different transit maps. These maps were varied with respect to color coding and level of street detail. Dependent variables of interest were planning time, accuracy, perceived difficulty, frustration, and confidence. Results indicated that when street detail was high, color coding of transit routes led to greater trip planning accuracy, less perceived difficulty, less frustration and higher confidence. When color coding was absent, greater street detail led to lower trip planning accuracy, greater perceived difficulty, greater frustration and lower confidence.
User Participation in Planning Environments
Authors: Wandersman Abraham
Published: March 2007

In this article, a conceptual framework of user participation in planning environments is proposed. The major elements of the framework include the parameters of participation (including type of participation), the effects of participation, mediators, and the role of individual difference variables as moderator variables and predictors of participation. Some potential uses of a framework of participation to researchers and planners are discussed. Participation as a value and as a technique is differentiated.
Environmental Effects Upon the Mobility of Older People
Authors: Carp Frances M.
Published: March 2007

This is a study of environmental determinants of mobility among older people, comparing mobility behaviors and attitudes among residents of two cities of similar size but markedly different in physical characteristics including size, shape, topography and climate, as well as distribution of facilities and services. Respondents were representative samples of 709 retired people in San Antonio, Texas, and 899 residents of San Francisco, California, aged 65 and older. Predictions of behavior and attitude based upon similarities and differences in environmental variables were confirmed. The data support the conclusion that urban environments strongly affect the mobility of their older residents and suggest that the design of cities can have a major and beneficial effect upon the quality of life in later years.
Room Utilization and Dimensions of Density
Authors: Mandel David R. , Baron Reuben M. , Fisher Jeffrey D.
Published: March 2007

Students in a high rise dormitory complex were surveyed to investigate the effects of floor height, view, and sex on perceptions of spaciousness and lightness of a room and evaluations of its decor. Height, and not view per se, was related to perceived spaciousness of one's room, with women on higher floors reporting their rooms more spacious than those on lower floors. Opposite results were obtained for men. Further, there were fewer posters and wall hangings on the upper floors than on the lower floors, and women were found to spend more time in their rooms and to decorate them more than men. Of related interest: while men showed no preference for a social or spatial definition of crowding, women significantly preferred a spatial definition. These findings are related to an optimal level of stimulation model and to sex differences in the dormitory literature.
Environmental Learning and Cognitive Mapping
Authors: Evans Gary W. , Marrero David G. , Butler Patricia A.
Published: March 2007

Microgenetic aspects of adult cognitive representations of large scale environments were examined for two samples. Multivariate analyses of variance revealed stable, parallel shifts in map construction for both samples. Landmarks appear to be used as initial anchor points in the environment with path structures elaborated subsequently within the initial landmark network. Further-more, basic ordinal accuracy of landmarks did not shift with experience, but exact location in space improved. The value of multidimensional scaling techniques and other multivariate techniques were also demonstrated.
Residential Satisfaction
Authors: Galster George C. , Hesser Garry W.
Published: March 2007

A theory of residential satisfaction is developed and used in the specification of a path model wherein compositional characteristics of households and the context of the dwelling and neighborhood in which they live influence various dimensions of satisfaction. Relationships are estimated for 767 households sampled in Wooster, Ohio, in 1975, using two-stage least-squares techniques. Results show that certain households demonstrate less satisfaction in any residential context, and that certain dwelling and neighborhood contexts elicit dissatisfaction across the full sample. Only a few such contextual factors prove significant in most compositional subsamples, indicating that different household types differently evaluate and/or adapt to similar contexts.
Has Public Housing Gotten a Bum Rap?
Authors: Farley John E.
Published: March 2007

Data were obtained from police on the incidence of crime in multiblock areas containing ten public housing developments in the city of St. Louis. The data covered eight FBI index crimes, and were obtained for seven years, 1971 through 1977. Crime rates per 100,000 population were computed. Seven of the public housing developments were large (over 500 units). There was a mix of lowrise and highrise developments, and conventionally and tenant-managed developments. The data indicate that the crime rates per 1000,000 population in and near the public housing developments are not significantly higher than in the city as a whole, nor are they higher than would be expected based on citywide relationships of crime to demographic and locational predictors. While there is more variation in the incidence of crimes in smaller developments than in larger ones, there is no evidence to support the belief that crime rates are, overall, higher than average in either type of development. It is also not possible from these data to identify any relationship between tenant management and crime rates, though other research has indicated that tenants feel safer in tenant-managed projects.
Professor Proxemics
Authors: Hensley Wayne E.
Published: March 2007

Investigating the use of office space as a nonverbal message, this study hypothesized that desk placement is used as a corroborating message rather than a predictive message. Measured educational attitudes on the part of university professors supported this hypothesis. In addition, situational demands, e.g., number of students taught and number of advisees, also seemed to affect desk placement. Regression analysis revealed an interaction among the variables making any simple classification schema hazardous. It was concluded that desk placement is a complex activity resulting from a host of personality orientations and job-related activities.
Crowding Perceptions, Attitudes, and Consequences among the Chinese
Authors: Loo Chalsa , Ong Paul
Published: March 2007

This article examines crowding in San Francisco's Chinatown and the attitudes and perceptions of its residents, using self-reported interview survey data. The objectives of the study were to test the validity of conjectures prevalent in the literature about the Chinese and crowding, to test Wirth's theory that crowding is related to psychological stress and social conflict, and to provide a fuller understanding of the nature of crowding and of density. Findings were contrary to the beliefs held about Chinese attitudes toward crowding; Chinatown residents evaluated crowding as undesirable and harmful. Personal effects of crowding included environmental health problems, social conflict, and psychological stress. Simultaneously, for a disadvantaged population, Wirth's theory was supported. Also, cultural background and environmental referent significantly predicted perceived crowding at the neighborhood level but did not affect perceptions of crowding at the dwelling level. Perceptions of dwelling crowding were instead heavily influenced by objective indices, that is, number of persons and number of rooms. Findings suggested that extended exposure to crowding breeds greater dislike for crowding at the micro level and that crowding in a primary environment is deemed more undesirable than crowding in a secondary environment.
Perception of Social Diversity and Fear of Crime
Authors: Kennedy Leslie W. , Silverman Robert A.
Published: March 2007

This article examines the influence of perceived social diversity on fear of crime among residents of urban neighborhoods. Perception of social diversity may lead to feelings of uncertainty in the environment, which in turn leads to increased levels of fear. Urban planning issues raised by perceived heterogeneity are addressed as are issues raised in the fear of crime literature. For purposes of analysis age is treated as a covariate and fear levels are related to both age groupings and to demographic and perception of diversity variables. Analysis reveals that levels of fear vary by age grouping and that the perceived social diversity variables affect the age groupings differentially.
Litter in a University Cafeteria
Authors: Durdan Catherine A. , Reeder Glenn D. , Hecht Peter R.
Published: March 2007

Litter behavior in a university cafeteria was studied. The research examined the effectiveness of various written behavioral prompts that urged patrons not to litter. Prompting resulted in a significant decrease in the litter. Of greater interest, positively worded prompts were more effective than negatively worded prompts. The specificity of the prompt, however, had no reliable effect. Several demographic variables were also examined. Persons in larger groups littered more than those in smaller groups, and males littered more than females. Also, prior to the introduction of the prompts, persons 25 years of age and older littered (nonsignificantly) more than younger persons. When prompts were in effect, however, this tendency was reversed, with older persons littering much less than younger persons. Finally, littering generally decreased as a function of the convenience of disposal facilities.
Neighborhood Satisfaction and Safety
Authors: Loo Chalsa
Published: March 2007

The aims of this study were (1) to test theories related to neighborhood satisfaction and safety and (2) to address planning and policy questions raised by a proposal for controls on development in San Francisco's Chinatown. Findings of an interview sample survey supported the urban scale, compositional, quality of local conditions, and urban anonymity perspectives. Results revealed a relationship between high population density/commercial development and lowered levels of neighborhood satisfaction as well as a relationship between increased building density and lesser feelings of safety in one's neighborhood. Increased development would be expected to exacerbate undesirable environmental qualities of the area and potentially destroy the ethnic enclave nature of the community. The margin of "affordable error" was judged to be small given the following factors: (1) lack of alternatives for this low income, nonmobile, immigrant, and Chinese monolingual population, (2) lower level of neighborhood satisfaction among Chinatown residents than U.S. residents overall, and (3) the greater neighborhood satisfaction experienced by the older, poorer, and nonaspiring and those whose neighboring relations constitute a form of community.
The Overseas Assignment Preferences of Japanese Managers
Authors: Everett James E. , Stening Bruce W.
Published: March 2007

The overseas assignment preferences of 76 Japanese managers being trained for overseas postings are analyzed, together with their assessments of ten potential destination cities on ten relevant evaluation criteria. A clear preference for Western postings is evident. Discriminant analysis based on the evaluation criteria is used to map the cities, and the discriminant map almost completely explains the mean preferences for the ten cities. The Japanese managers are found to be homogeneous in their preferences and assessments of overseas postings. The mean preferences for the cities are strongly related (over 98% explained variance) to the mean assessments on the evaluation criteria. In contrast, individual differences in preferences for the cities are only weakly related (7% explained variance) to individual differences in assessments on the evaluation criteria.
Evaluation of a Conceptual Model of Architectural Legibility
Authors: O'Neill Michael J.
Published: March 2007

Architectural legibility is the degree to which the designed features of the environment aid people in creating an effective mental image, or "cognitive map" of the spatial relationships within a building, and the subsequent ease of wayfinding within the environment. However, little research has attempted to operationalize legibility by examining the relationship between objective measures of the physical environment, the cognitive map, and observational measures of wayfinding performance. This article empirically assesses the effects of one environmental variable, topological floor plan complexity, on the cognitive mapping and wayfinding performance of 63 participants within three building settings. The study finds that this objective measure of floor plan complexity significantly influences cognitive mapping and observed wayfinding. Given these results, a conceptual model of one aspect of architectural legibility was developed and empirically tested. Path analysis was used to assess the relationship between topological plan configuration, four convergent measures of the cognitive map, and observational measures of human wayfinding performance. Analysis of these data provide support for the conceptual model. The model suggests that the complexity of topological plan configuration influences legibility. The evidence also indicates that the relationship between plan configuration and wayfinding is mediated by the accuracy of the cognitive map.
Risk-Taking Behaviors of College Students
Authors: Schneider Dona , Morris Joyce
Published: March 2007

It has been suggested that relaxed rules in dormitories encourage college students to engage in risky behaviors because they are free from the moral supervision of parents. Those who live off campus comprise another segment of students generally free from parental supervision. The authors surveyed 250 dormitory and 250 commuting students at Rutgers University and examined student patterns of risk-taking behavior. The survey contained questions on race, gender, academic standing, and multiple questions about risky behaviors. Four of those behaviors are discussed here in detail: smoking, alcohol abuse, drug abuse, and sexual behavior.
The Intrusion of Industrial Time and Space into the Inuit Lifeworld
Authors: Goehring Brian , Stager John K.
Published: March 2007

For the Inuit of the Arctic regions of Canada, contact with the "outside" world has been characterized by great changes both within their culture and in the ways their cultural values have been altered to incorporate perceptions of the rapidly changing world around them. In many ways, traditional conceptions of time and space have been readjusted to meet the demands of externally imposed industrial time and space. This article examines the nature of these changes and their impact on Inuit society. The implications of the experiencing of dramatic time-space compression, combined with rapid technological change are explored from a behavioral perspective. A reformulation of the culturally acceptable perceptions of the changing time and space parameters of imposed modernity characterizes Inuit society today, as individuals struggle to come to terms with the challenges of moving from preindustrial to postmodernist societies within the span of a single lifetime.
Placemaking by Design
Authors: Day Linda L.
Published: March 2007

This study of how people respond to design strategies for making new construction contextually compatible with the older buildings of a historic district is based on Amos Rapoport's theory of place meaning. The objective was to learn what elements of architecture help people find meaning in the built environment and to suggest ways that architects and policymakers can use this knowledge. Seventy-three people who were encountered in a public square across from a new megastructure were asked to do a multiple sort task using criteria of their own choice with 6 photos. Photos included an old facade that was used in the new building, other elevations of the new building, and old buildings around the square. The ways the old facade differed from the other elevations of the new building were noticed giving support to Rapoport's conclusion that people respond to the associations a place has with their own experience but they have to notice differences in what they see before they can make the association. The idea that place meaning would be effectively communicated by an obvious link to the community's past was not supported. Evidence of care being taken with the design of a building having an inviting public nature is more important than explicit links to the past.
Office Relocation and Environmental Change
Authors: Spreckelmeyer Kent F.
Published: March 2007

As office environments become more subject to rapid and continuous change, strategies must be developed to manage the resulting effects of increased levels of stress and dislocation on the part of office workers. Specifically, design strategies should be found that tend to minimize the impacts of environmental change and that enhance the nature of work itself. A postoccupancy evaluation (POE) measures the effects of environmental change within a single case study that used a number of behavioral and management techniques to improve worker satisfaction during the relocation of a governmental agency. Findings from the POE are compared to a national survey of office workers, and the results of the case study tend to reinforce the importance of small-scale attributes (lighting at the workstation, size of individual work surfaces, and office privacy) in contributing to positive ratings of occupant satisfaction in the workplace.
Beyond Design Review
Authors: Thiel Philip
Published: March 2007

Preconstruction public evaluation of proposed interventions in the physical environment (and postoccupancy evaluations of built projects) involve the lay public to an unprecedented degree as both virtual participants in the design process and as preeminent factors in the design considerations. The implications of these developments include the necessity for more specific identification of user groups and more experientially oriented means of performance specifications, environmental representation, and user response elicitation. The consequences will significantly affect design practice, education, and research as well as provide an empirical basis fordesign theory.
Chronic Noise Exposure and Reading Deficits
Authors: Evans Gary W. , Maxwell Lorraine
Published: March 2007

First- and second-grade schoolchildren chronically exposed to aircraft noise have significant deficits in reading as indexed by a standardized reading test administered under quiet conditions. These findings indicate that the harmful effects of noise are related to chronic exposure rather than interference effects during the testing session itself. We also provide evidence that the adverse correlation of chronic noise with reading is partially attributable to deficits in language acquisition. Children chronically exposed to noise also suffer from impaired speech perception, which, in turn, partially mediates the noise-exposure-reading deficit link. All of these findings statistically controlled for mother's education. Furthermore, the children in this study were prescreened for normal hearing by a standard audiometric examination.
Social Structural and Social Psychological Bases of Environmental Concern
Authors: Dietz Thomas , Stern Paul C. , Guagnano Gregory A.
Published: March 2007

Efforts to explain environmental concern as a function of social structure have revealed some weak but reliable associations. Stronger associations have been found between environmental concern and social psychological variables including attitudes, beliefs, and worldviews. The authors used the 1993 General Social Survey to explore a conceptual framework that postulates four causal levels: social structural factors and early socialization experiences; general worldview and ideology about humanity and the environment; specific attitudes, beliefs, and cognitions about environmental issues; and environmentally relevant behavior. Each class of variable has explanatory power beyond that given by other classes of variables, with the social psychological variables generally adding more explanatory power than the structural variables. The patterns are different, however, for the five behavioral indicators. Efforts to explain the structural influences as indirect, operating through the social psychological variables, were mainly unsuccessful.
The Affective Structure of Consumer Situations
Authors: Foxall Gordon , Greenley Gordon
Published: March 2007

Mehrabian and Russell argue that approach-avoidance behaviors in physical and social environments are determined by pleasure, arousal, and dominance. However, consumer research has not provided convincing evidence for the role of all three affective variables, largely because researchers used ad hoc settings, which failed to provide a theoretically coherent array of test environments. This study's authors used the Behavioral Perspective Model to examine the relationship between the affective and behavioral variables. Consumers (N = 561) responded to stimuli describing consumer situations, yielding data on 4,488 cases. The role of pleasure, arousal, and dominance as determinants of consumer behavior is demonstrated, and Mehrabian and Russell's finding of an important interaction between pleasure and arousal is confirmed. The importance of theoretically based research on consumer environments is substantiated, and dominance is shown to be a predictable response of consumers across relatively open (consumer-controllable) and relatively closed (marketer-controlled) settings.
Sociopolitical Transformation and the Media Environment
Authors: Tomaselli Keyan , Shepperson Arnold
Published: March 2007

In this article the authors develop a critical strategic analysis of the term `African Renaissance', which has become current in the discourse since first enunciated by Nelson Mandela. With the inauguration of Thabo Mbeki as Mandela's successor, the idea of an African Renaissance has taken root in the South African intellectual realm. The article considers the differences between `Renaissance' as a retrospective reconstruction of a specific history of modernity, and the idea of `Renaissance' as a projective strategy. Using the transformation of elements within South Africa's newspaper media from the 1980s into the period after 1994, the article argues that within the larger global transformation after 1988 there has arisen a need to reconceptualize modernity in terms of people's consciousness of a record. Comparing South Africa's transition from apartheid with Iran's transition to Islamic Republic, the authors conclude that without a multivocal media landscape the seeds of democratic government will wither.
Dutch Television Soap Opera, Ethnicity and Girls' Interpretations
Authors: de Bruin Joost
Published: March 2007

This article analyses the results of four exploratory group interviews with girls of Turkish, Surinamese and indigenous Dutch ethnic backgrounds. The groups watched a constructed episode of the Dutch soap opera Geode Tijden, Slechte Tijden ( Good Times, Bad Times), in which relational conflicts between parents and children were the central theme. The results show that the girls compared situations in the episode to their own lives and also referred to primordial `life values'. They actively negotiated with each other about what they would have done in a similar situation and what would have been the best way to behave. There were remarkable similarities across ethnic groups.
Language in Human Rights
Authors: Skutnabb-Kangas Tove , Phillipson Robert
Published: March 2007

Languages are today being killed at a much faster pace than ever before in human history and linguistic diversity is disappearing relatively faster than biological diversity. Still, linguistic diversity is as necessary for the existence of our planet as biodiversity, and the two are correlated. Linguistic human rights are a necessary (but not sufficient) prerequisite for the maintenance of linguistic diversity. Violations of linguistic human rights, especially in education, may lead to both ethnically articulated conflict and to reduction of linguistic and cultural diversity on our planet. The article analyses to what extent present linguistic human rights, especially in education, are sufficient to protect and maintain linguistic diversity and to function as the necessary corrective to the `free' market.
Media Literacy
Authors: Dyson Rose A.
Published: March 2007

As a critical component for communication in the coming years, media literacy means different things to different people. In the past decade, the emerging curriculum in schools has tended to include emphasis on decoding and deconstructing the meanings and messages in mass media in order to enable students to read between and beneath the lines and images. While there is much of importance and value in these initiatives, they continue to lack inculcation of child development and socializing theory in ways that would discourage defence of counterproductive themes in popular culture for children. At the same time, they underscore the need for a broader definition and more pervasive application of the concept.
Taking the Linguistic Turn in Organizational Research
Authors: Alvesson Mats , Kärreman Dan
Published: March 2007

This article takes the linguistic turn, or turns, in the social sciences as its point of departure and discusses the implications for methodology, empirical research, and field practices in social and organizational studies. Various responses can be identified: grounded fictionalism, giving up the hope of making substantive, empirical claims in terms of research texts capturing social phenomena; data-constructionism, where the ambiguous and constructed nature of empirical material gives space for a more relaxed, freer, and bolder way of interacting with empirical material; and discursivism, in which the researcher concentrates on the details of empirical material that lends itself to representations in the form of language, for example, conversations and texts. The article develops some ideas for a more reflective way of dealing with language issues in empirical social research. It argues for a more discourse-near but not discourse-exclusive approach to organizational research and refers to this as discursive pragmatism.
The Supermarxists and Pan-Africanism
Authors: Agyeman Opoku
Published: March 2007

I still feel it (Marxism) has been one of the most important phenomena in history and one of the greatest catalysts for change and transformation of society. The mistake of orthodox Marxists was to assume that the Manifesto, published in 1847, contained immutable scientific truth [Djilas, 1976]. I think I have said enough to make it understood that it is neither Marxism or Communism that I renounce, but it is the use that certain people have made of Marxism and Communism of which I disapprove. What I want is Marxism and Communism to be placed in the service of the black peoples and not the black peoples in the service of Marxism and Communism [Cesaire, 1956].
The Context and Development of Ola Rotimi at the Ori Olokun Theater
Authors: Coker Adeniyi
Published: March 2007

In ultimate terms, the writer and his matter belong to the people from whose cultural matrix his being and that matter derive. Herein lies the infinite sense of his relevance and lasting meaning of his matter. (Rotimi, personal conversation, 1990)
Strain Rate Effect on the Ultimate Tensile Stress of Fiber Epoxy Strands
Authors: Chiao T.T. , Moore R.L.
Published: March 2007

The strain rate effect on composite performance has been the subject of many arguments. This note points out some of the problems involved in measuring strain rate effect and presents our tensile data on some simple unidirectional composites.
Theoretical Post-Yielding Behavior of Composite Laminates Part I—Inelastic Micromechanics
Authors: Foye R.L.
Published: March 2007

This paper and a subsequent one will present the results of an investiga tion which analytically relates the fiber/matrix nonlinearities to the post- yielding behavior of symmetric laminates made from unidirectional plies. This first paper is primarily concerned with the behavior of the single ply and the means for anticipating its response within a laminate. Boron and carbon/epoxies are considered along with a metal matrix composite. The qualitative features of the response of these unidirectional materials to normal, shear, and combined loads are discussed. The analysis (based on triangular finite element idealizations of regularly-spaced inclusion arrays) anticipates the level of nonlinearity that has been observed in composite shear and transverse tensile tests. Also, it reveals a nonlinear coupling that may exist between the combined shear and normal stress response.
The Stochastic Finite Element Simulation of Parallel Fiber Composites
Authors: Larder Richard A. , Beadle Charles W.
Published: March 2007

A method is presented of simulating the randomly occurring damage in a parallel fiber composite subject to static loading. A three-dimensional finite element is used for the matrix material and a two-node truss element for the fibers. Individual fiber strengths vary randomly along their lengths and a series of problems are solved, successively accounting for the failure of the lowest strength remaining fiber. Stress concentration effects intro duced by fiber failure are considered. Force-deflection curves are obtained. Failure stress of the entire model can be estimated by observing the num ber of fiber failures per load increment.
Plastic Flow Rule of Laminated Composites
Authors: Pei Chi Chou  , Chou David K.
Published: March 2007

A plastic flow rule for laminated media is derived. It is based on a three-dimensional lamination theory which has been used previously to provide an effective elastic stress-strain relation and an anisotropic yield condition. For layers that are isotropic and follow a piece-wise linear flow rule, an explicit anisotropic plastic stress-strain relation for the equivalent composite is obtained. The general form of this flow rule may also be applied to other homogeneous but anisotropic materials. It is concluded that anisotropic flow rules should be governed by tensor quantities, the symmetry of flow may be different from that of yielding, and plastic flow may occur under hydrostatic loading.
Stresses Around Pin-Loaded Holes in Elastically Orthotropic or Isotropic Plates
Authors: De Jong Theo
Published: March 2007

The stress distribution round a pin-loaded hole in an elastically ortho tropic or isotropic plate is investigated. The hole is loaded frictionless on only a part of its edge by an infinitely rigid pin of the same diameter. The loading force is carried over on the edge by normal stresses, represented by a sine series. It is shown that these stresses depend strongly on the material properties. Infinite plate results are used to estimate the stresses in plates nite width. Numerical results are shown graphically for three laminates n fibre reinforced plastic and for three ratios of width of plate to mole diameter.
Stress Field Induced by Transient Moisture Sorption in Finite-Width Composite Laminates
Authors: Crossman Frank W. , Wang A.S.D.
Published: March 2007

To describe the moisture sorption process in a long, finite-width com posite laminate, the two-dimensional diffusion equation is solved using a finite element method. The solution which describes the time-varying moisture concentration profile in the solid, is then incorporated in the calculation of the elastic stress field induced by moisture swelling. Time- varying stress concentrations are found present near the free edge region. The moisture sorption history is shown to be important in the evaluation of the laminate's residual stress field.

This is the concluding paper in a series of three by the authors, which study the hygrothermal and mechanical aspects of free-edge effects in composite laminates by means of elastic finite element analysis.
Finite Element Microscopic Stress Analysis of Cracked Composite Systems
Authors: Ko William L.
Published: March 2007

This paper considers the stress concentration problems of two types of cracked composite systems: (1) a composite system with a broken fiber (a penny-shaped crack problem), and (2) a composite system with a cracked matrix (an annular crack problem).

The cracked composite systems are modeled with triangular and trap ezoidal ring finite elements. Using NASTRAN (NASA Structural Analysis) finite element computer program, the stress and deformation fields in the cracked composite systems are calculated. The effect of fiber-matrix mate rial combination on the stress concentrations and on the crack opening displacements is studied.
Investigation of Angle-Ply Delamination Specimen For Interlaminar Strength Test
Authors: Harris Alexander , Orringer Oscar
Published: March 2007

The use of fiber composite laminates in many structural applications requires that the designer be provided with accurate information about interlaminar strength. In particular, a knowledge of interlaminar tensile strength may be important in some cases. The delamination coupon, a specially designed angle-ply laminate developed by other investigators, is considered here in the role of an interlaminar tension test specimen. Exper imental results obtained with the delamination coupon suggest that the current procedure for design of such specimens must be changed to reduce the effect of interlaminar shear stress on the results, and that more accur ate analysis must be used before interlaminar tensile strength can be pre dicted with confidence.
The Predicted and Experimental Natural Modes of Free-Free CFRP Plates
Authors: Cawley Peter , Adams Robert D.
Published: March 2007

This paper describes an investigation into the natural modes of free-free laminated composite plates. Theoretical and experimental natural fre quencies and mode shapes are presented for the first six flexural modes of a square aluminium plate and for square CFRP plates of different ply orientations; results are also given for a trapezoidal CFRP plate. The the oretical predictions were made by using an 8-node, 40 degree of freedom shell finite element which allows for transverse shear deformation. The agreement between theoretical and experimental frequencies is good, the worst error being 6.3 per cent. The results indicate that the element pro vides a useful tool in the analysis of laminated composite structures.
The Natural Modes of Graphite/Epoxy Cantilever Plates and Shells
Authors: Crawley Edward F.
Published: March 2007

The natural frequencies and mode shapes of a number of Graphite/ Epoxy and Graphite/Epoxy-Aluminum plates and shells were experimen tally determined. The samples tested include 8 ply Graphite/Epoxy plates, cyclindrical shell sections, and Graphite/Epoxy-Aluminum hybrid plates of various laminates and aspect ratio. Fabrication and test procedures are described. Natural frequency and mode shape results are compared with those calculated by a finite element analysis. Agreement between calcu lated and observed mode shapes is excellent; while reasonable agreement is found for frequencies. Among the sources of this discrepancy in frequency results is the possibility of a difference between dynamic-flexural moduli and static in-plane moduli.
The Thermal Expansion Behavior of Unidirectional and Bidirectional Kevlar/Epoxy Composites
Authors: Strife James R. , Prewo Karl M.
Published: March 2007

The coefficients of thermal expansion, α, of unidirectionally and bi directionally reinforced Kevlar 49/PR-286 composites are reported for the temperature range 25-150°C. Composite thermal expansion is shown to be highly anisotropic with the variation in α considerably greater for multi- axially reinforced composites than for unidirectional composites. Compar ison with data for HTS graphite/epoxy composites demonstrates that the thermal expansion behavior of Kevlar/epoxy composites is considerably more anisotropic.

Elastic properties are also reported and coupled with the thermal expan sion data, calculations based on various models for predicting thermal expansion behavior are presented. It is shown that calculated values of thermal expansion are in close agreement with those measured.
Moisture Absorption of Polyester-E Glass Composites
Authors: Loos Alfred C. , Springer George S. , Sanders Barbara A. , Tung Randy W.
Published: March 2007

Moisture absorption of polyester-E glass composites immersed in liquids and in humid air were investigated. The weights of the composites as a function of exposure time and temperature were measured for three differ ent types of materials. Tests were performed a) with the materials im mersed in distilled water, in saturated salt water, in No. 2 diesel fuel, in jet A fuel, in synthetic aviation lubricant, in gasoline, and b) with the materi als exposed to humid air. The apparent maximum moisture contents and the apparent diffusivities were deduced from the data.
A Dynamic Explanation of The Hybrid Effect
Authors: Xing JI , Hsiao George C. , Chou Tsu-Wei
Published: March 2007

A theoretical analysis has been performed to evaluate the dynamic stress concentration factor in hybrid composites composed of low elongation (LE) and high elongation (HE) fibers. At a fracture of a fiber, the present model predicts two stress waves propagating along each fiber in the hybrid. The phase difference of the dynamic responses contributed by these waves at the middle section of a fiber immediately adjacent to a fiber breakage is controll ed by the fiber mass per unit length. The magnitude of the dynamic responses is determined by the fiber extensional stiffness. The study concludes that hybrid effect always exists in a beneficial manner and the case of the parent LE fiber composite provides the upper bound for the dynamic stress concen tration factor in hybrids. The validity of the approximations made in the derivations has been examined.
Interlaminar Fracture of Composite Materials
Authors: Jurf Robert A. , Pipes R. Byron
Published: March 2007

Interlaminar fracture characteristics of a graphite/epoxy composite material (AS1/3501-6) are investigated under the opening, shearing and mix ed mode conditions. The Arcan test fixture was modified to accomodate the composite specimen containing an embedded interlaminar crack. Both critical stress intensity factor and strain energy release rate data were deter mined and the quadratic interaction for mixed mode behavior was compared to experimental data. Results of over sixty tests showed that the test fixture yielded results which compare favorably with results from contemporary test fixtures. Critical fracture parameters for the opening and shearing modes were shown to differ by a factor of 9.1. Further, the test results showed general agreement with the quadratic interaction relation.
Optimal Design of High Speed Rotating Graphite/Epoxy Shafts
Authors: Bauchau Oliver A.
Published: March 2007

An important problem in the design of a high speed rotating shaft of significant span is the lateral stability. With light weight Graphite/Epoxy material it is relatively easy to meet the torsional stiffness and strength requirements using a thin walled tube, but this might lead to a shaft which is sensitive to lateral buckling. This paper will address the following question: Is it possible to increase the first natural bending frequency of the shaft through an adequate tapering of the wall thickness? A numerical procedure using a generalized criterion of optimality is outlined. The shaft was modeled using a beam formulation including shear deformation and rotary inertia. The optimization was done under constant volume constraint. Different configurations are studied for various number of plies and orientation angle. In the optimal configuration the natural frequency increased by about 21 to 44%, and the bending stress decreased by about 48 to 59%.
The Effect of Geometry on Interlaminar Stresses of [0/90]s Composite Laminates with Circular Holes
Authors: Lucking W.M. , Hoa S.V. , Sankar T.S.
Published: March 2007

The effect of the radius to thickness ratio R/t on the interlaminar stresses around the hole in a [0/90]s composite laminate containing a circular hole and loaded in uniaxial tension was investigated. Three dimensional finite elements with a technique that is similar to substructuring were used for the analysis. The results show that as the ratio R/t increases, the magnitude of the tangential interlaminar shear stress on the interface between the crossed plies and near the hole edge increases. Also, as the ratio R/t in creases, the maximum of the interlaminar normal stress on the midplane near the hole increases and its position on the hole edge shifts towards the transverse axis where other stresses are also maximum.
The Effect of Laminate Configuration on Characteristic Lengths and Rail Shear Strength
Authors: Chang Fu-Kuo , Scott Richard A. , Springer George S.
Published: March 2007

Tests were performed measuring the characteristic lengths in tension and in com pression and the rail shear strength of Fiberite T300/1034-C graphite epoxy com posites. The results show the effects of geometry on the characteristic lengths. The results also indicate the variability of rail shear strength with the volume fraction of zero degree plies in the laminate.
Non-Destructive Evaluation of Fatigue Damage in Alumina Fiber Reinforced Aluminum
Authors: Tsangarakis N. , Gruber J.J. , Nunes J.
Published: March 2007

Thermography, ultrasonic and limited x-ray radiography techniques were employed to identify fatigue damage in alumina fiber reinforced aluminum plates with a centered circular hole. Metallographic examination identified the damage as longitudinal and transverse cracks, which were frequently associated with striation markings in the metal matrix. These striation markings suggest that the aluminum matrix was plastically deformed within a damage zone adjacent to the hole. The length of the cracks iden tified by the ultrasonic techniques varied between 0.40-6.50 mm. There are indications that the size and the location of the fatigue damage may be assessed thermographically.