A three-dimensional shoulder protector based on ergonomics for workers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ran-i Eom ◽  
Yejin Lee
Keyword(s):  
Body Shape ◽  
Three Dimensional ◽  
Health And Safety ◽  
The Body ◽  
Construction Sites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Functional Studies ◽  
Work Posture ◽  
Dimensional Printing

PurposeThe use of shoulder protectors is strongly recommended when carrying objects on the shoulder to ensure the health and safety of workers. Thus, this study aimed to develop and verify an ergonomic shoulder protector that considers human body shape and carrying posture from an ergonomic perspective. Ultimately, this study will present a shoulder protector with enhanced fit and safety for carrying workers at construction sites.Design/methodology/approachThe shoulder protector was designed and printed using three-dimensional printing technology with variable side neck points and shoulder point heights to reflect the human body's shoulder line shape and to position the carried object stably on the shoulder. The developed shoulder protectors were evaluated in terms of their fit according to the work posture of the carrier, adherence upon motion and durability through structural analysis.FindingsThe design of the shoulder protector for carrying workers followed the shoulder line. It is best placed above the side neck point by 1.0 cm and above the shoulder point by 2.0 cm. Its length is slightly shorter than the human shoulder for superior fit and safety.Originality/valueThe final shoulder protector (FSP) for carrying workers reflects the body curvature while enhancing fit and safety by considering activity and protective factors. As functional studies and evaluations on the need for protectors are scarce, this study provides fundamental data in the evaluation of protective gears.

Rapid manufacturing of copper-graphene composites using a novel rapid tooling technique

2020 ◽  
Vol 26 (4) ◽  
pp. 765-776 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak Mohan Pandey
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Rate Coefficient ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Dimensional Printing

Purpose The purpose of this study is to study the mechanical, tribological and electrical properties of the copper-graphene (Cu-Gn) composites fabricated by a novel rapid tooling technique consist of three-dimensional printing and ultrasonic-assisted pressureless sintering (UAPS). Design/methodology/approach Four different Cu-Gn compositions with 0.25, 0.5, 1 and 1.5 per cent of graphene were fabricated using an amalgamation of three-dimensional printing and UAPS. The polymer 3d printed parts were used to prepare mould cavity and later the UAPS process was used to sinter Cu-Gn powder to acquire free-form shape. The density, hardness, wear rate, coefficient of friction and electrical conductivity were evaluated for the different compositions of graphene and compared with the pure copper. Besides, the comparison was performed with the conventional method. Findings Cu-Gn composites revealed excellent wear properties due to higher hardness, and the lubrication provided by the graphene. The electrical conductivity of the fabricated Cu-Gn composites started increasing initially but decreased afterwards with increasing the content of graphene. The UAPS fabricated composites outperformed the conventional method manufactured samples with better properties such as density, hardness, wear rate, coefficient of friction and electrical conductivity due to homogeneous mixing of metal particles and graphene. Originality/value The fabrication of Cu-Gn composite freeform shapes was found to be difficult using conventional methods. The novel technique using a combination of polymer three-dimensional printing and UAPS as rapid tooling was introduced for the fabrication of freeform shapes of Cu-Gn composites and mechanical, tribological and electrical properties were studied. The method can be used to fabricate optimized complex Cu-Gn structures with improved wear and electrical applications.

A review of 3D concrete printing systems and materials properties: current status and future research prospects

2018 ◽  
Vol 24 (4) ◽  
pp. 784-798 ◽  
Author(s):  
Suvash Chandra Paul ◽  
Gideon P.A.G. van Zijl ◽  
Ming Jen Tan ◽  
Ian Gibson
Keyword(s):  
Three Dimensional ◽  
Current Status ◽  
Future Research ◽  
Structural Elements ◽  
Construction Time ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Materials Research ◽  
Printing System ◽  
Dimensional Printing

Purpose Three-dimensional printing of concrete (3DPC) has a potential for the rapid industrialization of the housing sector, with benefits of reduced construction time due to no formwork requirement, ease of construction of complex geometries, potential high construction quality and reduced waste. Required materials adaption for 3DPC is within reach, as concrete materials technology has reached the point where performance-based specification is possible by specialists. This paper aims to present an overview of the current status of 3DPC for construction, including existing printing methods and material properties required for robustness of 3DPC structures or structural elements. Design/methodology/approach This paper has presented an overview of three categories of 3DPC systems, namely, gantry, robotic and crane systems. Material compositions as well as fresh and hardened properties of mixes currently used for 3DPC have been elaborated. Findings This paper presents an overview of the state of the art of 3DPC systems and materials. Research needs, including reinforcement in the form of bars or fibres in the 3D printable cement-based materials, are also addressed. Originality/value The critical analysis of the 3D concrete printing system and materials described in this review paper is original.

scholarly journals Remanufacturing of end-of-life glass-fiber reinforced composites via UV-assisted 3D printing

2019 ◽  
Vol 26 (6) ◽  
pp. 981-992
Author(s):  
Andrea Mantelli ◽  
Marinella Levi ◽  
Stefano Turri ◽  
Raffaella Suriano
Keyword(s):  
Mechanical Properties ◽  
Circular Economy ◽  
Three Dimensional ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Glass Fiber Reinforced ◽  
Complex Shapes ◽  
Dimensional Printing

Purpose The purpose of this study is to demonstrate the potential of three-dimensional printing technology for the remanufacturing of end-of-life (EoL) composites. This technology will enable the rapid fabrication of environmentally sustainable structures with complex shapes and good mechanical properties. These three-dimensional printed objects will have several application fields, such as street furniture and urban renewal, thus promoting a circular economy model. Design/methodology/approach For this purpose, a low-cost liquid deposition modeling technology was used to extrude photo-curable and thermally curable composite inks, composed of an acrylate-based resin loaded with different amounts of mechanically recycled glass fiber reinforced composites (GFRCs). Rheological properties of the extruded inks and their printability window and the conversion of cured composites after an ultraviolet light (UV) assisted extrusion were investigated. In addition, tensile properties of composites remanufactured by this UV-assisted technology were studied. Findings A printability window was found for the three-dimensional printable GFRCs inks. The formulation of the composite printable inks was optimized to obtain high quality printed objects with a high content of recycled GFRCs. Tensile tests also showed promising mechanical properties for printed GFRCs obtained with this approach. Originality/value The novelty of this paper consists in the remanufacturing of GFRCs by the three-dimensional printing technology to promote the implementation of a circular economy. This study shows the feasibility of this approach, using mechanically recycled EoL GFRCs, composed of a thermoset polymer matrix, which cannot be melted as in case of thermoplastic-based composites. Objects with complex shapes were three-dimensional printed and presented here as a proof-of-concept.

Classification of body shape characteristics of women's torsos using angles

2010 ◽  
Vol 22 (4) ◽  
pp. 297-311 ◽  
Author(s):  
Wookyung Lee ◽  
Haruki Imaoka
Keyword(s):  
Body Shape ◽  
Three Dimensional ◽  
The Body ◽  
Data Set ◽  
Content Type ◽  
Body Sizes ◽  
Body Shapes ◽  
Three Body ◽  
Shape Characteristics

PurposeThe purpose of this paper is to classify body shapes using angular defects instead of sizes.Design/methodology/approachA large amount of dimensional data from a national anthropometry survey was analysed, and a basic pattern and its polyhedron were also used to create a three‐dimensional body shape from three body sizes. Using this method, the sizes were converted into nine angular defects.FindingsThe authors could define the factors explaining body shape characteristics and classify the body shapes into four groups. The four groups could be characterised by two pattern making difficulties of the upper and lower parts of the body as well as by two proportions, of waist girth to bust girth and bust girth to back length. Furthermore, depending on the age, the authors could understand body shape by the angle made.Originality/valueUsing a polyhedron model, the angles could be calculated using an enormous existing data set of sizes. An angular defect serves as an index to indicate the degree of difficulty for developing a flat pattern. If an angular defect of the bust is large, it is difficult to make a paper pattern of a bust dart. On the other hand, if an angular defect of the waist is large, it is easy to make a paper pattern of a waist dart. Thus, each body shape could be simultaneously characterized by two difficulty indices and two proportions of sizes.

Barriers to the implementation of COVID-19 safety regulations: insight from Ghanaian construction sites

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fredrick Simpeh ◽  
Emmanuel Bamfo-Agyei ◽  
Christopher Amoah
Keyword(s):  
Health And Safety ◽  
The Body ◽  
Snowball Sampling ◽  
Construction Sites ◽  
Content Type ◽  
Implementation Challenges ◽  
Construction Firms ◽  
Body Of Knowledge ◽  
Safety Regulations ◽  
Data Collection Instrument

Purpose The new normal introduced by COVID-19 has ushered in new safety regulations that are required to be implemented by all organisations, including the construction industry. The implementation of the COVID-19 regulations, like any health and safety regulation, is not without hindrances. Consequently, this study aims to explore factors hindering the implementation of COVID-19 safety regulations at construction sites in Ghana. Design/methodology/approach The study adopted a qualitative research method using an open-ended questionnaire as a data collection instrument. The set of questionnaires were distributed by means of purposive and snowball sampling methods. The collected data were analysed by means of the thematic analysis technique. Findings It became evident that several factors militate against implementing COVID-19 safety regulations at construction sites. Cost of implementing COVID-19 safety measures, lack of compliance and ignorance were identified as the most hindering factors, whereas superstition, lack of personal protective equipment supply and theft of COVID-19 materials were reported by fewer respondents. Research limitations/implications The set of questionnaires were limited to small construction firms who were operating on site within the Central, Western and Greater Accra regions of Ghana during the second wave of the COVID-19 pandemic. However, the findings may be applicable to firms outside these regions because most of the small construction firms in the country share similar characteristics. Practical implications The recommendations proffered could help construction organisations devise strategies to overcome the barriers that hamper the implementation of COVID-19 safety regulations on site. Moreover, the findings could inform policymakers on what is required to enforce compliance on site. Originality/value COVID 19 is still new, and as a result, the body of knowledge is at the infancy stage. This article contributes to advancing the body of knowledge in the area of COVID-19 implementation challenges on construction sites.

Classification of challenges in 3D printing for combined electrochemical and microfluidic applications: a review

2019 ◽  
Vol 25 (7) ◽  
pp. 1328-1346 ◽  
Author(s):  
Arivarasi A. ◽  
Anand Kumar
Keyword(s):  
Manufacturing Sector ◽  
Three Dimensional ◽  
Cost Effective ◽  
Scientific Output ◽  
Integrated Process ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Cost Effective Approach ◽  
Dimensional Printing ◽  
Process Material

Purpose The purpose of this paper is to describe, review, classify and analyze the current challenges in three-dimensional printing processes for combined electrochemical and microfluidic fabrication areas, which include printing devices and sensors in specified areas. Design/methodology/approach A systematic review of the literature focusing on existing challenges is carried out. Focused toward sensors and devices in electrochemical and microfluidic areas, the challenges are oriented for a discussion exploring the suitability of printing varied geometries in an accurate manner. Classifications on challenges are based on four key categories such as process, material, size and application as the printer designs are mostly based on these parameters. Findings A key three-dimensional printing process methodologies have their unique advantages compared to conventional printing methods, still having the challenges to be addressed, in terms of parameters such as cost, performance, speed, quality, accuracy and resolution. Three-dimensional printing is yet to be applied for consumer usable products, which will boost the manufacturing sector. To be specific, the resolution of printing in desktop printers needs improvement. Printing scientific products are halted with prototyping stages. Challenges in three-dimensional printing sensors and devices have to be addressed by forming integrated processes. Research limitations/implications The research is underway to define an integrated process-based on three-dimensional Printing. The detailed technical details are not shared for scientific output. The literature is focused to define the challenges. Practical implications The research can provide ideas to business on innovative designs. Research studies have scope for improvement ideas. Social implications Review is focused on to have an integrated three-dimensional printer combining processes. This is a cost-oriented approach saving much of space reducing complexity. Originality/value To date, no other publication reviews the varied three-dimensional printing challenges by classifying according to process, material, size and application aspects. Study on resolution based data is performed and analyzed for improvements. Addressing the challenges will be the solution to identify an integrated process methodology with a cost-effective approach for printing macro/micro/nano objects and devices.

Vanillin-based thiol-ene systems as photoresins for optical 3D printing

2019 ◽  
Vol 26 (2) ◽  
pp. 402-408 ◽  
Author(s):  
Aukse Navaruckiene ◽  
Sigita Kasetaite ◽  
Jolita Ostrauskaite
Keyword(s):  
Mechanical Properties ◽  
Real Time ◽  
Design Methodology ◽  
Three Dimensional ◽  
Insoluble Fraction ◽  
Content Type ◽  
Three Dimensional Printing ◽  
First Time ◽  
Dimensional Printing ◽  
Kinetics Of

Purpose This study aims to present a design and investigation of novel vanillin-based thiol-ene photocurable systems as candidate materials for optical three-dimensional printing. Design/methodology/approach Two vanillin acrylates, vanillin dimethacrylate and vanillin diacrylate, were tested in thiol-ene photocurable systems with 1,3-benzenedithiol. The kinetics of photocross-linking was investigated by real-time photorheometry using two photoinitiators, diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide or ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate in different quantities. The dependencies of rheological properties of resins on the used vanillin derivative, photoinitiator, and the presence of a solvent, as well as structure, thermal and mechanical properties of the selected polymers were investigated. Findings The most rigid polymers were obtained from vanillin diacrylate-based resins without any solvent. The vanillin diacrylate-based polymer possessed higher values of cross-linking density, the yield of insoluble fraction, thermal stability and better mechanical properties in comparison to the vanillin dimethacrylate-based polymer. Originality/value The kinetics of photocross-linking of vanillin-based thiol-ene systems was investigated by real-time photorheometry for the first time. The designed novel photocurable systems based on vanillin acrylates and 1,3-benzenedithiol are promising renewable photoresins for optical three-dimensional printing on demand.

Friction and wear characteristics of polylactic acid (PLA) for 3D printing under reciprocating sliding condition

2019 ◽  
Vol 72 (4) ◽  
pp. 533-539
Author(s):  
Peng Zhang ◽  
Zhichao Hu ◽  
Huanxiong Xie ◽  
Gwang-Hee Lee ◽  
Chul-Hee Lee
Keyword(s):  
Polylactic Acid ◽  
Oscillation Frequency ◽  
Friction And Wear ◽  
Three Dimensional ◽  
Wear Properties ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Friction And Wear Properties ◽  
Dimensional Printing ◽  
Friction And Wear Characteristics

Purpose This paper aims to study the different infill, printing direction against sliding direction and various load condition for the friction and wear characteristics of polylactic acid (PLA) under reciprocating sliding condition. Design/methodology/approach The tests were performed by applying the load of 1, 5, 15 and 10 N with sliding oscillation frequency of 10 Hz for the duration of 10 min at room temperature. Findings The results show that the friction and wear properties of PLA specimen change with a different infill density of printed parts. The oscillation frequency is 10 Hz and the infill density of plate is 50 per cent that shows the best friction and wear properties. Originality/value The potential of this research work is to investigate the tribological characteristics of three-dimensional printing parts with different infill percentage to provide a reference for any parts in contact with each other to improve friction and wear performance. There will be many opportunities exist for further research and the advancement of three-dimensional printing in the field of tribology.

Process capability study of three dimensional printing as casting solution for non ferrous alloys

2016 ◽  
Vol 22 (3) ◽  
pp. 474-486 ◽  
Author(s):  
Rajesh Kumar ◽  
Rupinder Singh ◽  
IPS Ahuja
Keyword(s):  
Research Work ◽  
Three Dimensional ◽  
Process Capability ◽  
Dimensional Accuracy ◽  
Ferrous Alloy ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Casting Solution ◽  
Measuring Machine ◽  
Dimensional Printing

Purpose The purpose of this paper is to investigate the process capability of three-dimensional printing (3DP)-based casting solutions for non-ferrous alloy (NFA) components. Design/methodology/approach After selection and design of benchmark, prototypes for six different NFA materials were prepared by using 3DP (ZCast process)-based shell moulds. Coordinate measuring machine has been used for calculating the dimensional tolerances of the NFA components. Consistency with the tolerance grades of the castings has been checked as per IT grades. Findings The results of process capability investigation highlight that the 3DP process as a casting solution for NFA component lies in ±5sigma (s) limit, as regards to dimensional accuracy is concerned. Further, this process ensures rapid production of pre-series industrial prototypes for NFA. Final components prepared are also acceptable as per ISO standard UNI EN 20,286-I (1995). Originality/value This research work presents capability of the 3DP process supported with experimental data on basis of various process parameters for the tolerance grade of NFA castings. These statistics can help to enhance the application of 3DP-based NFA casting process in commercial foundry industry.

Effects of mixture ingredients on interlayer adhesion of concrete in Contour Crafting

2018 ◽  
Vol 24 (3) ◽  
pp. 584-592 ◽  
Author(s):  
Babak Zareiyan ◽  
Behrokh Khoshnevis
Keyword(s):  
Empirical Model ◽  
Design Methodology ◽  
Large Scale ◽  
Three Dimensional ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Contour Crafting ◽  
Model Condition ◽  
Dimensional Printing ◽  
Significant Factors

Purpose This paper aims to investigate the strength at interlayer of specimens fabricated using Contour Crafting (CC) to develop a concrete mixture for large-scale three-dimensional printing. Design/methodology/approach The collected data from several experiments were analyzed to understand significant factors and their interactions. After developing the empirical model, condition for maximum desirability was identified and the model was validated. Findings The experimental investigation of varied combination of concrete components introduced an empirical model which can predict the strength at interface. Moreover, an optimized mixture within constrains of the CC nozzle was developed and validated. Originality/value Several experimental samples were tested, and the derived empirical model was validated after more than 600 h of work.

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