Search results

1 – 10 of 874
Article
Publication date: 5 November 2020

Nan Zhang, Lichao Zhang, Senlin Wang, Shifeng Wen and Yusheng Shi

In the implementation of large-size additive manufacturing (AM), the large printing area can be established by using the tiled and fixed multiple printing heads or the single…

Abstract

Purpose

In the implementation of large-size additive manufacturing (AM), the large printing area can be established by using the tiled and fixed multiple printing heads or the single dynamic printing head moving in the xy plane, which requires a layer decomposition after the mesh slicing to generate segmented infill areas. The data processing flow of these schemes is redundant and inefficient to some extent, especially for the processing of complex stereolithograph (STL) models. It is of great importance in improving the overall efficiency of large-size AM technics software by simplifying the redundant steps. This paper aims to address these issues.

Design/methodology/approach

In this paper, a method of directly generating segmented layered infill areas is proposed for AM. Initially, a vertices–mesh hybrid representation of STL models is constructed based on a divide-and-conquer strategy. Then, a trimming–mapping procedure is performed on sliced contours acquired from partial surfaces. Finally, to link trimmed open contours and inside-signal square corners as segmented infill areas, a region-based open contour closing algorithm is carried out in virtue of the developed data structures.

Findings

In virtue of the proposed approach, the segmented layered infill areas can be directly generated from STL models. Experimental results indicate that the approach brings us the good property of efficiency, especially for complex STL models.

Practical implications

The proposed approach can generate segmented layered infill areas efficiently in some cases.

Originality/value

The region-based layered infill area generation approach discussed here will be a supplement to current data process technologies in large-size AM, which is very suitable for parallel processing and enables us to improve the efficiency of large-size AM technics software.

Details

Rapid Prototyping Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Open Access
Article
Publication date: 5 March 2020

Fredrik Brunes, Cecilia Hermansson, Han-Suck Song and Mats Wilhelmsson

This paper aims to analyze how nearby property prices are affected by new construction projects in Stockholm. If there is an impact on property prices, the authors endeavor to…

3004

Abstract

Purpose

This paper aims to analyze how nearby property prices are affected by new construction projects in Stockholm. If there is an impact on property prices, the authors endeavor to investigate whether the effects vary among different areas within the municipality, for different groups of inhabitants and for different types of housing (i.e. public versus private housing).

Design/methodology/approach

The authors use a difference-in-difference specification in a hedonic model, and the sample consists of more than 90,000 observations over the period 2005-2013.

Findings

The results are robust and indicate that house prices in nearby areas increase following the completion of infill development. The results also indicate that infill development has a positive spillover effect on nearby dwelling prices only in areas with lower incomes, more public housing units and more inhabitants born abroad.

Originality/value

It provides an analysis on how nearby property prices are affected by new construction projects by creating a restricted control area, so as to make the treatment group and the control group more homogeneous. Thus, it mitigates any potential problems with spatial dependency, which can cause biased standard errors.

Details

Journal of European Real Estate Research , vol. 13 no. 1
Type: Research Article
ISSN: 1753-9269

Keywords

Article
Publication date: 13 July 2022

Şenol Şirin, Enes Aslan and Gülşah Akincioğlu

The purpose of this study is the investigation of the friction performance of 3D-printed polylactic acid (PLA) at different infill densities.

812

Abstract

Purpose

The purpose of this study is the investigation of the friction performance of 3D-printed polylactic acid (PLA) at different infill densities.

Design/methodology/approach

PLA samples were printed with fused filament fabrication (FFF). Friction performance test of PLA samples were performed under 18 N load at 20 min, 40 min and 60 min using a pin-on-disc tester. Diameter deviation, hardness of 3D-printed PLA, weight variation, coefficient of friction, temperature and wear images were chosen as performance criteria.

Findings

The hardness values of the samples with 30%, 50% and 70% infill density were determined as 93.9, 99.93 and 102.67 Shore D, respectively. The friction of coefficient values obtained in these samples at 20 min, 40 min and 60 min were measured as 0.5737, 0.4454 and 0.3824, respectively. The least deformation occurred in the sample with 50% occupancy rate and during the test period of 20 min.

Practical implications

The aim of this study was to determine the best friction performance of 3D-printed biodegradable and biocompatible PLA with different infill densities.

Originality/value

In the literature, several studies can be found on the mechanical characteristics of 3D-printed parts produced with PLA. However, investigations on the wear characterisation of these parts are very limited. In this regard, the friction coefficient results obtained from different infill density of 3D-printed PLA used in this study will significantly contribute to the literature.

Details

Rapid Prototyping Journal, vol. 29 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 April 2022

Hu Chen, Kenan Ma, Yongsheng Zhou, Yong Wang and Yuchun Sun

This in vitro study aims to explore the effects of selective laser melting (SLM) process parameters on the accuracy of the intaglio surface of cobalt–chromium alloy (Co–Cr)…

Abstract

Purpose

This in vitro study aims to explore the effects of selective laser melting (SLM) process parameters on the accuracy of the intaglio surface of cobalt–chromium alloy (Co–Cr), commercially pure titanium (CP Ti) and titanium alloy (Ti–6Al–4V) maxillary removable partial denture (RPD) frameworks and optimize these process parameters.

Design/methodology/approach

Maxillary RPD framework specimens designed on a benchmark model were built. The process parameters, including contour scan speed and laser power, infill scan speed and laser power, hatch space, build orientation and metallic powder type, were arranged through the Taguchi design. Three-dimensional deviations of the clasps area, connector area and overall area of maxillary RPD frameworks were analyzed by using root mean square (RMS) as a metric. One-way analyses of variance with the above RMSs as the dependent variable were carried out (α = 0.05).

Findings

Maxillary RPD frameworks built horizontally had a more accurate intaglio surface than those built at other orientation angles; CP Ti or Ti–6Al–4V maxillary RPD frameworks had a more accurate intaglio surface than Co–Cr ones; the Maxillary RPD framework built with a higher infill scan speed and lower infill laser power had the more accurate intaglio surface than the one built with other levels of these two process parameters.

Originality/value

A novel benchmark model for evaluating the accuracy of the intaglio surface of maxillary RPD frameworks manufactured by SLM is proposed. The accuracy of the intaglio surface of maxillary RPD frameworks can be improved by adjusting SLM process parameters. The optimal setting of process parameters concerning the accuracy of the intaglio surface of maxillary RPD frameworks was given.

Details

Rapid Prototyping Journal, vol. 28 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Open Access
Article
Publication date: 8 May 2018

Rolf Barlindhaug and Berit Irene Nordahl

This paper aims to investigate whether developers’ ask lower prices on homes in redevelopment sites than they do on similar units in smaller developments completed over a shorter…

2991

Abstract

Purpose

This paper aims to investigate whether developers’ ask lower prices on homes in redevelopment sites than they do on similar units in smaller developments completed over a shorter time span. It also investigates whether developers price units differently at different stages of the redevelopment process. The development of designated redevelopment areas often consists of multiple projects spread across several years, some in parallel, some sequential. New units are put on the market in a piecemeal fashion, and infrastructure, shared green spaces and shared facilities are installed successively.

Design/methodology/approach

A hedonic price model is used to analyse sales prices of 7,000 new apartments in Oslo sold between 2011 and 2015, all else being equal. The paper distinguishes between infill as one-stage projects, and multi-staged competitive and multi-staged monopolistic redevelopments.

Findings

Dwellings in redevelopment projects sell at a lower price than similar dwellings in infill projects. In competitive redevelopments, those in charge of the last projects put a slightly higher price on apartments. In redevelopments involving only one developer, the last stages ask the lowest prices.

Research limitations/implications

This research expands our understanding of developers’ pricing behaviour. Developers supplying housing for the private market through redevelopments land are willing to take risks particularly in the initial stage.

Practical implications

The findings indicate that credit institutions financing developers’ projects need to take into account the structure of selling prices, including lower prices and higher risk of pursuing redevelopment projects.

Social implications

Gaining a better understanding of developers’ pricing behaviour deepens our insights into the dynamics of market-led urban brownfield developments; this knowledge may moreover inform policies on sustainable urban growth.

Originality/value

An original investigation of housing transactions in urban brownfield sites in Oslo provides fresh insights into developers’ pricing behaviour.

Details

Journal of European Real Estate Research, vol. 11 no. 1
Type: Research Article
ISSN: 1753-9269

Keywords

Article
Publication date: 3 September 2020

Morteza Jamshidi, Heydar Dashti NaserAbadi and Mohammadreza Oliaei

The high heat induced by fire can substantially decrease the load-bearing capacity, which is more critical in unprotected steel structures than concrete reinforced structures. One…

Abstract

Purpose

The high heat induced by fire can substantially decrease the load-bearing capacity, which is more critical in unprotected steel structures than concrete reinforced structures. One of the conventional steel structures is a steel-plate shear wall (SPSW) in which thin infill steel plates are used to resist against the lateral loads. Due to the small thickness of infill plates, high heat seems to dramatically influence the lateral load-bearing capacity of this type of structures. Therefore, this study aims to provide an investigation into the performance of SPSW with reduced beam section at high temperature.

Design/methodology/approach

In the present paper, to examine the seismic performance of SPSW at high temperature, 48 single-span single-story steel frames equipped with steel plates with the thicknesses of 2.64 mm, 5 mm and 7 mm and yield stresses of 85 MPa, 165 MPa, 256 MPa and 300 MPa were numerically modeled. Furthermore, their behavioral indices, namely, strength, stiffness, ductility and hysteresis behavior, were studied at the temperatures of 20, 458, 642 and 917? The simulated models in the present paper are based on the experimental specimen presented by Vian and Bruneau (2004).

Findings

The obtained results revealed that the high heat harshly diminishes the seismic performance of SPSW so that the lateral strength is reduced even by 95% at substantially high temperatures. Therefore, SPSW starts losing its strength and stiffness at high temperature such that it completely loses its capacity of strength, stiffness and energy dissipation at the temperature of 917? Moreover, it was proved that by separating the percentage of their participations variations of the infill plate in SPSW, their behavior and the bare frame can be examined even at high temperatures.

Originality/value

To the best of the authors’ knowledge, the seismic performance of SPSW at different temperatures has not been evaluated and compared yet.

Details

Journal of Structural Fire Engineering, vol. 11 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 1 March 2015

Kazunobu Minami

Apartment houses in Japan now face many serious problems. Japanese society is aging, resulting in 1 or 2 elderly people now living in houses built for larger households consisting…

Abstract

Apartment houses in Japan now face many serious problems. Japanese society is aging, resulting in 1 or 2 elderly people now living in houses built for larger households consisting of 3 or more people. This has distorted the structure of the population residing in apartments, so they do not function as district communities. To ensure the future effective utilization of our housing stock, we must tackle one fundamental challenge, namely developing methods of flexibly upgrading the existing housing stock to respond to change of the makeup of the population of regional societies and to changing life styles. Housing production and supply systems that enable residents to personally plan and decide specifications must be introduced to establish infill upgrading as an effectively functioning part of the future housing market.

Details

Open House International, vol. 40 no. 1
Type: Research Article
ISSN: 0168-2601

Keywords

Article
Publication date: 3 October 2016

Antti Tapio Kurvinen and Jaakko Vihola

Even as multi-story apartment building development proposals in existing neighbourhoods represent a substantial component of policy debate at local planning boards, there is…

1159

Abstract

Purpose

Even as multi-story apartment building development proposals in existing neighbourhoods represent a substantial component of policy debate at local planning boards, there is limited evidence for the impact of such residential developments on surrounding apartment values. This paper aims to address the void in knowledge, and the impact of multi-story apartment building developments on apartment values in residential high-rise areas located outside city and district centres is investigated in Helsinki Metropolitan Area, Finland.

Design/methodology/approach

Whether a multi-story apartment building development is followed by an increase in housing values depends on both positive and negative externalities. To specify valuation effects of proximate development projects, advanced research design combining matched sample methodology and hedonic-based difference-in-difference approach is used.

Findings

It appears from the analysis that completion of a single multi-story apartment building has an immediate positive impact on apartment values within 300 metre radius, while there is no statistically significant impact on price trend.

Research limitations/implications

This paper studies apartment values only in Helsinki Metropolitan Area, Finland, and it is important to notice that local regulations and market conditions may have a notable impact on the outcomes.

Originality/value

This study is the first of its kind to provide with statistically significant evidence for positive impacts from multi-story apartment building development in Finnish residential high-rise areas and may have a crucial role in helping to dispel prejudices related to such developments.

Details

International Journal of Housing Markets and Analysis, vol. 9 no. 4
Type: Research Article
ISSN: 1753-8270

Keywords

Article
Publication date: 12 July 2021

Matt Schmitt and Il Yong Kim

In furthering numerical optimization techniques for the light-weighting of components, it is paramount to produce algorithms that closely mimic the physical behavior of the…

Abstract

Purpose

In furthering numerical optimization techniques for the light-weighting of components, it is paramount to produce algorithms that closely mimic the physical behavior of the specific manufacturing method under which they are created. The continual development in topology optimization (TO) has reduced the difference in the optimized geometry from what can be physically realized. As the reinterpretation stage inevitably deviates from the optimal geometry, each progression in the optimization code that renders the final solution more realistic is beneficial. Despite the efficacy of material extrusion (MEx) in producing complex geometries, select manufacturing constraints are still required. Thus, the purpose of this paper is to develop a TO code which demonstrates the incorporation of MEx specific manufacturing constraints into a numerical optimization algorithm.

Design/methodology/approach

A support index is derived for each element of the finite element mesh that is used to penalize elements, which are insufficiently supported, discouraging their existence. The support index captures the self-supporting angle and maximum allowable bridging distance for a given MEx component. The incorporation of the support index into a TO code is used to demonstrate the efficacy of the method on multiple academic examples.

Findings

The case studies presented demonstrate the methodology is successful in generating a resulting topology that is self-supporting given the manufacturing parameters specified in the code. Comparative to a general TO problem formulation, the optimal material distribution results in a minimally penalized design on a compliance normalization metric while fully adhering to the MEx specific parameters. The methodology, thus, proves useful in generating an infill geometry is fully enclosed regions, where support material extraction is not a possibility.

Originality/value

The work presented is the first paper to produce a novel methodology that incorporates the manufacturing-specific constraint of bridging distance for MEx into TO code. The results generated allow for the creation of printed components with hollow inclusions that do not require any additional support material beyond the intended structure. Given the advancement, the numerical optimization technique has progressed to a more realistic representation of the physical manufacturing method.

Details

Rapid Prototyping Journal, vol. 27 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 November 2019

Christopher J. Whitman, Oriel Prizeman, Pete Walker and Julie Amanda Gwilliam

The energy retrofit of the existing building stock, and specifically the thermal upgrading of the buildings’ envelopes, has been identified as a key action for both the…

Abstract

Purpose

The energy retrofit of the existing building stock, and specifically the thermal upgrading of the buildings’ envelopes, has been identified as a key action for both the decarbonisation of the built environment and the reduction in fuel poverty. When considering the energy retrofit of heritage buildings it is, however, important to recognise both the technical issues that this entails and the potential impact on their cultural value and the emotional responses to it. The purpose of this paper is to focus on the thermal upgrading of historic timber-framed buildings in the UK.

Design/methodology/approach

The paper begins by exploring the cultural significance of this form of building construction, before examining three case studies using both quantitative and qualitative methodologies.

Findings

The results show that whilst the application of energy retrofit actions to this emblematic typology may have limited success, the emotional connection of the buildings’ occupants often results in the work resulting in higher user satisfaction than would otherwise be expected.

Research limitations/implications

Although limited in number, the three case studies provide an insight into the complex issues surrounding the low energy retrofit of historic timber-framed buildings. Further research into this area is encouraged.

Practical implications

The paper contains the monitoring of specific retrofit details, the results of which should inform future projects.

Social implications

The review of the cultural significance of historic timber-frame buildings in the UK underlines the importance of the conservation and continuing survival of these buildings.

Originality/value

Previous heritage retrofit research in the UK has focussed on solid wall construction with little investigation into the issues surrounding the retrofit of historic timber-frame buildings. This paper explores this previously under-researched area. Additionally, this paper begins to explore the possible links between occupants’ emotional connection to historic buildings and their perceived levels of comfort.

Details

International Journal of Building Pathology and Adaptation, vol. 38 no. 2
Type: Research Article
ISSN: 2398-4708

Keywords

1 – 10 of 874