AbstractThis paper presents an experimental study that investigated the physical, mechanical, and durability characteristics of newly developed vinylester- and polyester-based glass-fiber-reinforced ...polymer (GFRP) dowels through a collaboration research project with the Ministry of Transportation of Québec (MTQ). Durability performance was first evaluated with a preliminary set of conditionings in different solutions. The long-term performance was then assessed under harsh alkaline exposure simulating the concrete environment. The alkaline exposure was achieved by immersing the dowels in an alkaline solution at elevated temperatures to accelerate the effects. Thereafter, the properties were assessed and compared with the unconditioned reference values. The test parameters were (1) type of resin (vinylester and polyester), (2) diameter of GFRP dowels (25.4–44.8 mm), (3) temperature (23, 50, and 60°C), and (4) conditioning time (30, 60, and 180 days). The test results revealed that the vinylester-based GFRP dowels were stable and did not show significant changes in their properties after being subjected to an alkaline solution for 180 days at 60°C. The long-term predictions revealed that the transverse shear-strength retention of vinylester- and polyester-based GFRP dowels would decrease by 10 and 26%, respectively, after 100 years at 10°C. Based on the findings of this research, a new material specification for GFRP dowels was formulated by the MTQ in order to ensure product performance and longevity.
Based on years of airworthiness regulations research, combined with the experience of airworthiness certification of civil aviation products, the airworthiness requirement to materials for civil ...aviation products was analyzed. The key airworthiness requirement for materials is that materials should conform to some material specification to ensure their having the strength and other properties adopted in the design data. The shortcomings of domestic airworthiness management methods for civil aviation materials was discussed and three recommendations for improvement were proposed:(1) conduct individual airworthiness management for civil aviation materials according to CCAR 21.351 through 371 and CCAR 37; (2) develop and promote statistical-based material specification developing methods, to establish material specifications which could ensure material having the strength and other properties adopted in the design data; (3) establish a cooperation mechanism for developing material design value data base for civi
Abstract
Die Normenreihe DIN 18204 „Bauteile aus textilen Flächengebilden und Folien” wurde in den letzten zwei Jahren umfassend überarbeitet. Neben der Aktualisierung von Normenbezügen wurde die ...Struktur grundlegend geändert, so dass sie in zukünftig zu entwickelnden weiteren Normenteilen neben den Zelthallen weitere Strukturen aus textilen Flächengebilden und Folien regeln kann. Die Materialspezifikationen wurden entschlackt und auf neue Prüfnormen angepasst. Des Weiteren wurde das Bemessungskonzept behutsam überarbeitet. Der vorliegende Beitrag beschreibt die Hintergründe, zeigt detailliert die Änderungen zur Vorgängernorm und gibt einen Ausblick auf die endgültige Fassung.
Abstract
Tents and halls made of PVC‐coated polyester fabric according to the updated standard series DIN 18204.
The standard series DIN 18204 ”Components for enclosures made of textile fabrics and plastic films (awnings)“ has been extensively reviewed in the last two years. Alongside with updates of normative references, the structure has been fundamentally changed so that the standard can also cover additional textile and plastic structures in new parts to be developed in future. Material specifications have been purified and adapted to new test standards. Moreover, the design concept has been gently revised. The present contribution describes the background, illustrates the changes compared to the previous edition and provides an outlook to the final version.
Die Normenreihe DIN 18204 „Bauteile aus textilen Flächengebilden und Folien” wurde in den letzten zwei Jahren umfassend überarbeitet. Neben der Aktualisierung von Normenbezügen wurde die Struktur ...grundlegend geändert, so dass sie in zukünftig zu entwickelnden weiteren Normenteilen neben den Zelthallen weitere Strukturen aus textilen Flächengebilden und Folien regeln kann. Die Materialspezifikationen wurden entschlackt und auf neue Prüfnormen angepasst. Des Weiteren wurde das Bemessungskonzept behutsam überarbeitet. Der vorliegende Beitrag beschreibt die Hintergründe, zeigt detailliert die Änderungen zur Vorgängernorm und gibt einen Ausblick auf die endgültige Fassung.
Tents and halls made of PVC‐coated polyester fabric according to the updated standard series DIN 18204. The standard series DIN 18204 ”Components for enclosures made of textile fabrics and plastic films (awnings)“ has been extensively reviewed in the last two years. Alongside with updates of normative references, the structure has been fundamentally changed so that the standard can also cover additional textile and plastic structures in new parts to be developed in future. Material specifications have been purified and adapted to new test standards. Moreover, the design concept has been gently revised. The present contribution describes the background, illustrates the changes compared to the previous edition and provides an outlook to the final version.
This study proposes that the impact of the built environment on the natural environment can be mediated by adopting a sustainable approach to building material selection and specification, ...particularly when articulated at the design stage of the building process. The aim is to identify the main drivers and barriers to sustainable material specification by built environment design professionals. This study carried out for Cyprus where attempts have been made to uncover the attitudes of Cypriot built environment design professionals towards the natural environment, identify the process employed in specifying building materials, and the extent to which they draw inspirations from the natural environment.
Additive manufacturing (AM) maintains a wide process window that enables complex designs otherwise unattainable via conventional production technologies. However, the lack of confidence in qualifying ...AM parts that leverage AM process–structure–property–performance (PSPP) relationships stymies design optimization and adoption of AM. While continuing efforts to map fundamental PSPP relationships that cover the potential design space, we first need pragmatic and then long-term solutions that overcome challenges associated with qualifying AM-designed parts. Two pragmatic solutions include: (1) AM material specifications to substantiate process reproducibility, and (2) component risk categorization to associate system risk relative to part performance and required part quality. A novel qualification paradigm under development involves efficient prediction of part performance over wide-ranging PSPP relationships through targeted testing and computational simulation. Here this paper describes projects at Sandia National Laboratories on PSPP relationship discovery, these pragmatic approaches, and the novel qualification approach.
Abstract
The harsh Australian environment makes the use of steel reinforcement in concrete structures problematic on account of corrosion. The probability of corrosion damage will significantly ...increase in the years to come and will become a major problem not only in coastal regions but also in inland parts of Australia due to increasing carbon dioxide concentration, temperature, and relative humidity as a consequence of climate change. In the last two decades, glass fiber-reinforced polymer (GFRP) composite bars have become an alternative to steel reinforcement for reinforcing concrete structures exposed to harsh environments. The reinforcing material is noncorrodible, nonmagnetic, lightweight, and has high tensile strength, thus making it a viable reinforcing material for concrete structures. This paper provides the state-of-the-practice in the research, development, and application of GFRP bars, with the aim of properly informing the engineering community about this alternative, noncorrodible reinforcing technology. The paper also presents a strategy toward the development of fiber-reinforced polymer bar material specifications with the aim to ensure quality use and application of the GFRP material in a wide range of applications in Australia in the years to come. Moreover, the best practices and data presented in this paper will be very useful in the development of unified international standards and specifications for GFRP bars.
► Introduce literature on extraction, processing & specification of soft materials. ► Examine soft materials’ esthetic, functional, economical & environmental criteria. ► Conduct a survey involving ...manufactures, designers & end-users of soft materials. ► Generate response rates, boxplots & ANOVA to study data interaction & variation. ► Conclude samples’ marginal consideration of environmental factors in soft materials.
Sustainable soft materials in design applications should aim to have less resources depletion and pollution, plus inevitably less toxicity for the entire ecosystem. The outcome would result in environmental benefits, particularly with the production, specification and usage of proper materials. For this purpose, the paper conducted a survey among manufactures, designers and end-users to explore the concerns related to the inconsequential consideration of environmental factors associated with the extraction, processing, fabrication, and selection process of soft materials. Four criteria, including aesthetical, functional, economical, and environmental, were examined based on a comprehensive set of 33 governing factors. The analysis concludes criteria response rates that capture the intensity of the respondents experience using a three-point Likert scale. Analysis of Variance (ANOVA) was further considered to determine differences and interaction between independent and dependent variables. Results show that the main effect for criteria is not significant, but there are mean differences in consideration of criteria when respondents are evaluating factors based on the rating scale. Overall, the interaction variation and plots highlight the statistically significant differences between criteria. The environmental criterion is of marginal importance to all populations.
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