scholarly journals Optimization of design variables for carbon/glass hybrid composites laminates using the Taguchi Technique

2020 ◽  
Vol 17 (2) ◽  
pp. 309-323
Author(s):  
Sagar Dnyandev Patil ◽  
Yogesh J. Bhalerao ◽  
Adik Takale
Keyword(s):  
Mechanical Properties ◽  
Composite Laminate ◽  
Hybrid Composites ◽  
Carbon Layer ◽  
Stacking Sequence ◽  
Strengthening Effect ◽  
Content Type ◽  
Design Variables ◽  
Laminate Thickness ◽  
The Impact

Purpose The purpose of this paper is to analyze the significance of disparate design variables on the mechanical properties of the composite laminate. Four design variables such as stacking sequence, stacking angle, types of resins and thickness of laminate have been chosen to analyze the impact on mechanical properties of the composite laminate. The detailed investigation is carried out to analyze the effect of a carbon layer in stacking sequence and investigate the impact of various resins on the fastening strength of fibers, stacking angles of the fibers and the thickness of the laminate. Design/methodology/approach The Taguchi approach has been adopted to detect the most significant design variable for optimum mechanical properties of the hybrid composite laminate. For this intend, L16 orthogonal array has been composed in statistical software Minitab 17. To investigate an effect of design variables on mechanical properties, signal to noise ratio plots were developed in Minitab. The numerical analysis was done by using the analysis of variance. Findings The single parameter optimization gives the optimal combination A1B1C4D2 (i.e. stacking sequence C/G/G/G, stacking angle is 00, the type of resin is newly developed resin [NDR] and laminate thickness is 0.3 cm) for tensile strength; A4B2C4D2 (i.e. stacking sequence G/G/G/C, stacking angle is 450, the type of resin is NDR and laminate thickness is 0.3 cm) for shear strength; and A2B3C4D2 (i.e. stacking sequence G/C/G/G, stacking angle is 900, the type of resin is NDR and thickness is 0.3 cm) for flexural strength. The types of resins and stacking angles are the most significant design variables on the mechanical properties of the composite laminate. Originality/value The novelty in this study is the development of new resin called NDR from polyethylene and polyurea group. The comparative study was carried out between NDR and three conventional resins (i.e. polyester, vinyl ester and epoxy). The NDR gives higher fastening strength to the fibers. Field emission scanning electron microscope images illustrate the better fastening ability of NDR compared with epoxy. The NDR provides an excellent strengthening effect on the RCC beam structure along with carbon fiber (Figure 2).

scholarly journals Multi-objective optimization of carbon/glass hybrid composites with newly developed resin (NDR) using gray relational analysis

2020 ◽  
Vol 16 (6) ◽  
pp. 1709-1729
Author(s):  
Sagar Dnyandev Patil ◽  
Yogesh J. Bhalerao
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Hybrid Composites ◽  
Research Work ◽  
Optimum Combination ◽  
Gray Relational Analysis ◽  
Stacking Sequence ◽  
Content Type ◽  
Relational Analysis ◽  
Design Variables

PurposeIt is seen that little amount of work on optimization of mechanical properties taking into consideration the combined effect of design variables such as stacking angle, stacking sequence, different resins and thickness of composite laminates has been carried out. The focus of this research work is on the optimization of the design variables like stacking angle, stacking sequence, different resins and thickness of composite laminates which affect the mechanical properties of hybrid composites. For this purpose, the Taguchi technique and the method of gray relational analysis (GRA) are used to identify the optimum combination of design variables. In this case, the effect of the abovementioned design variables, particularly of the newly developed resin (NDR) on mechanical properties of hybrid composites has been investigated.Design/methodology/approachThe Taguchi method is used for design of experiments and with gray relational grade (GRG) approach, the optimization is done.FindingsFrom the experimental analysis and optimization study, it was seen that the NDR gives excellent bonding strength of fibers resulting in enhanced mechanical properties of hybrid composite laminates. With the GRA method, the initial setting (A3B2C4D2) was having GRG 0.866. It was increased by using a new optimum combination (A2B2C4D1) to 0.878. It means that there is an increment in the grade by 1.366%. Therefore, using the GRA approach of analysis, design variables have been successfully optimized to achieve enhanced mechanical properties of hybrid composite laminates.Originality/valueThis is an original research work.

scholarly journals Effect of Secondary Carbon Nanofillers on the Electrical, Thermal, and Mechanical Properties of Conductive Hybrid Composites Based on Epoxy Resin and Graphite

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4169
Author(s):  
Marcel Zambrzycki ◽  
Krystian Sokolowski ◽  
Maciej Gubernat ◽  
Aneta Fraczek-Szczypta
Keyword(s):  
Mechanical Properties ◽  
Specific Surface ◽  
Epoxy Resin ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hybrid Composites ◽  
Department Of Energy ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Secondary Carbon

In this work, we present a comparative study of the impact of secondary carbon nanofillers on the electrical and thermal conductivity, thermal stability, and mechanical properties of hybrid conductive polymer composites (CPC) based on high loadings of synthetic graphite and epoxy resin. Two different carbon nanofillers were chosen for the investigation—low-cost multi-layered graphene nanoplatelets (GN) and carbon black (CB), which were aimed at improving the overall performance of composites. The samples were obtained by a simple, inexpensive, and effective compression molding technique, and were investigated by the means of, i.a., scanning electron microscopy, Raman spectroscopy, electrical conductivity measurements, laser flash analysis, and thermogravimetry. The tests performed revealed that, due to the exceptional electronic transport properties of GN, its relatively low specific surface area, good aspect ratio, and nanometric sizes of particles, a notable improvement in the overall characteristics of the composites (best results for 4 wt % of GN; σ = 266.7 S cm−1; λ = 40.6 W mK−1; fl. strength = 40.1 MPa). In turn, the addition of CB resulted in a limited improvement in mechanical properties, and a deterioration in electrical and thermal properties, mainly due to the too high specific surface area of this nanofiller. The results obtained were compared with US Department of Energy recommendations regarding properties of materials for bipolar plates in fuel cells. As shown, the materials developed significantly exceed the recommended values of the majority of the most important parameters, indicating high potential application of the composites obtained.

COMPUTATIONAL MODELING OF EPOXY-BASED HYBRID COMPOSITES REINFORCED WITH CARBON FIBERS AND FUNCTIONALIZED GRAPHENE NANOPLATELETS

2021 ◽  
Author(s):  
HASHIM AL MAHMUD ◽  
, MATTHEW RADUE ◽  
WILLIAM PISANI ◽  
GREGORY ODEGARD
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Hybrid Composites ◽  
Graphene Nanoplatelets ◽  
Pristine Graphene ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Aspect Ratios ◽  
The Impact ◽  
Nanoscale Level

The impact on the mechanical properties of unidirectional carbon fiber (CF)/epoxy composites reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and Functionalized Graphene Oxide (FGO) are investigated in this study. The localized reinforcing effect of each of the graphene nanoplatelet types on the epoxy matrix is predicted at the nanoscale-level by molecular dynamics. The bulk-level mechanical properties of unidirectional CF/epoxy hybrid composites are predicted using micromechanics techniques considering the reinforcing function, content, and aspect ratios for each of the graphene nanoplatelets. In addition, the effect of nanoplatelets dispersion level is also investigated for the pristine graphene nanoplatelets considering a lower dispersion level with four layers of graphene nanoplatelets (4GNP). The results indicate that the shear and transverse properties are significantly affected by the nanoplatelet type, loading and aspect ratio. The results of this study can be used in the design of hybrid composites to tailor specific laminate properties by adjusting nanoplatelet parameters.

Improving service employee work affect: the transformative potential of work design

2014 ◽  
Vol 28 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Steven W. Rayburn
Keyword(s):  
Self Determination Theory ◽  
Psychological Needs ◽  
Work Design ◽  
Self Determination ◽  
Interactive Effects ◽  
Specific Work ◽  
Content Type ◽  
Design Variables ◽  
Work Affect ◽  
The Impact

Purpose – The purpose of this article is to employ Self-Determination Theory to explain the mediated impact of work design – empowerment and serial and investiture socialization – on employee work affect. The theory proposes fulfilment of three psychological needs – autonomy, competence, and relatedness – will mediate individuals' ability to achieve contextually relevant well-being. An empirical study tests this claim and exposes the structure of the mediating effects. Design/methodology/approach – Survey responses were collected from a sample of 239 front-line service employees using snowball data collection. SEM was used to test hypotheses. Findings – Findings suggest that empowerment and serial and investiture socialization are significantly differentially related to need fulfilment. Additionally, all forms of need fulfilment do not directly influence employee affect. Instead, there are both direct and interactive effects that work simultaneously to influence employees' positive work affect. Practical implications – This study exposes specific work design levers managers can manipulate to benefit employees. This research highlights the different effects of specific work design variables on employee work affect. Originality/value – This paper extends understanding of Self-Determination Theory by exposing the direct and interactive effects of need fulfilment on work affect for service workers. Also, it delivers a deeper exploration of the impact of work design on employees by modelling multiple work design variables as well as process variables simultaneously to provide a more detailed picture of how work design influences employee work affect.

Assessment of the mechanical properties of different textile materials used for outer shell of bulletproof vest: woven fabrics for military applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
A.I.H. Fayed ◽  
Y.A. Abo El Amaim ◽  
Ossama Ramy ◽  
Doaa H. Elgohary
Keyword(s):  
Mechanical Properties ◽  
Woven Fabrics ◽  
Outer Shell ◽  
Common Mechanism ◽  
Content Type ◽  
Textile Materials ◽  
Steel Core ◽  
Materials Used ◽  
Bulletproof Vest ◽  
The Impact

Purpose This paper aims to investigate the performance of four different textile materials used as an outer shell of the bulletproof vest. Design/methodology/approach In this paper, four different textile materials were used, polyurethane treatment was applied as a surface coating for the woven samples. Mechanical properties were conducted for all samples; scanning electron microscope and X-ray energy disperse spectroscopy were executed to show the surface morphology of samples and the chemical composition of the coating material. Findings One-way ANOVA was used to statistically analyse the results, which proved that all variables were highly significantly affected by using different textile materials, despite the stiffness variable being not significantly affected by textile materials. An overall evaluation was done using radar chart, demonstrated that Cordura material accomplished the best functional performance, using two types of calibres 7.62 × 54 mild steel core and 7.62 × 54 armour piercing incendiary; the common mechanism was localized burn because of the incendiary effect of the projectile in addition to tearing mechanism starting from inside because of penetration effect of the steel core. Originality/value This work was addressed to analyse the impact of using four different materials on its performance as the outer shell of bulletproof vest to achieve the desired degree of protection.

Effect of layer thickness on irreversible thermal expansion and interlayer strength in fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 943-953 ◽  
Author(s):  
Anthony A. D’Amico ◽  
Analise Debaie ◽  
Amy M. Peterson
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Layer Thickness ◽  
Fused Deposition Modeling ◽  
Thermal Strain ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
The Impact

Purpose The aim of this paper is to examine the impact of layer thickness on irreversible thermal expansion, residual stress and mechanical properties of additively manufactured parts. Design/methodology/approach Samples were printed at several layer thicknesses, and their irreversible thermal expansion, tensile strength and flexural strength were determined. Findings Irreversible thermal strain increases with decreasing layer thickness, up to 22 per cent strain. Tensile and flexural strengths exhibited a peak at a layer thickness of 200 μm although the maximum was not statistically significant at a 95 per cent confidence interval. Tensile strength was 54 to 97 per cent of reported values for injection molded acrylonitrile butadiene styrene (ABS) and 29 to 73 per cent of those reported for bulk ABS. Flexural strength was 18 to 41 per cent of reported flexural strength for bulk ABS. Practical implications The large irreversible thermal strain exhibited that corresponding residual stresses could lead to failure of additively manufactured parts over time. Additionally, the observed irreversible thermal strains could enable thermally responsive shape in additively manufactured parts. Variation in mechanical properties with layer thickness will also affect manufactured parts. Originality/value Tailorable irreversible thermal strain of this magnitude has not been previously reported for additively manufactured parts. This strain occurs in parts made with both high-end and consumer grade fused deposition modeling machines. Additionally, the impact of layer thickness on tensile and flexural properties of additively manufactured parts has received limited attention in the literature.

Experimental Investigation on Mechanical Properties of Carbon-Flax-Glass Hybrid Composites

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Dinesh ◽  
R. Asokan ◽  
S. Vignesh ◽  
Chitikena Phani Kumar ◽  
Rajulapati Ravichand
Keyword(s):  
Mechanical Properties ◽  
Thermal Load ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Natural Fibers ◽  
Thermal Exposure ◽  
Stacking Sequence ◽  
Specific Strength ◽  
Hybrid Laminates ◽  
Fiber Materials

Over the years, application of composite materials has got wider. So there is a necessity for development of new materials to satisfy the environmental requirements. It is viable through the process of hybridization of natural fibers to synthetic fibers. This investigation is carried out to determine the tensile and flexural strength of hybrid composites with various fiber combinations and stacking sequence. Thus it is easy to identify the natural fiber hybrid combination with high mechanical properties under static and varying thermal load conditions. The various fiber materials are meticulously chosen and three conventional and six different hybrid laminates were fabricated with various stacking sequences of selected fibers using hand layup technique. The tensile and flexural properties are determined through mechanical testing and compared with conventional materials. The failure morphologies are captured and investigated with zoom optical cameras. On analyzing the results, it is observed that carbon-flax hybrid composites exhibit nearly equivalent specific strength at a reduced cost compared to the carbon/glass fiber hybrid composites and also the effect of the stacking sequence in mechanical properties is elucidated through this study. Varying thermal load analysis reveals that there is a considerable loss in mechanical properties due to thermal exposure.

scholarly journals The influence of urban design packages on home values

2017 ◽  
Vol 10 (2) ◽  
pp. 184-203
Author(s):  
Christopher Bitter ◽  
Andy Krause
Keyword(s):  
Urban Design ◽  
Positive Impact ◽  
Residential Home ◽  
Design Element ◽  
Hedonic Price ◽  
Neighborhood Design ◽  
Content Type ◽  
Design Variables ◽  
Home Values ◽  
The Impact

Purpose The purpose of this study is to examine the impact of neighborhood design templates on residential home values in King County, WA, USA. Previous research examines a number of individual design factors; this study combines these factors into typologies and tests for the impacts of the composite set of design features. Design/methodology/approach The study analyzes over 27,000 home sales with a hedonic price model to measure the impacts across three large, regional submarkets. Neighborhood design categories are developed using a cluster analysis on a set of individual neighborhood attributes. Findings The key finding from this research is that the impact of more traditional (“urban”) design packages on home values is highly contextual. For the older and denser neighborhoods in the study area, a more traditional design results in a significantly positive impact on home values. In the new and more suburban regions of the study area, this effect is not found. Originality/value Prior work focused on valuing design attributes individually. The study argues that neighborhood design is better conceived of as a “package”, as the value of a given design element may depend on other co-located attributes. This is the first study, to the authors’ knowledge, to treat physical neighborhood design variables as a composite whole and to attempt to value their impact on home values as such.

scholarly journals The impact of process parameters on mechanical properties of parts fabricated in PLA with an open-source 3-D printer

2015 ◽  
Vol 21 (5) ◽  
pp. 604-617 ◽  
Author(s):  
Antonio Lanzotti ◽  
Marzio Grasso ◽  
Gabriele Staiano ◽  
Massimo Martorelli
Keyword(s):  
Mechanical Properties ◽  
Open Source ◽  
Process Parameters ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Testing Machine ◽  
Main Process ◽  
Content Type ◽  
Fused Deposition ◽  
The Impact

Purpose – This study aims to quantify the ultimate tensile strength and the nominal strain at break (ɛf) of printed parts made from polylactic acid (PLA) with a Replicating Rapid prototyper (Rep-Rap) 3D printer, by varying three important process parameters: layer thickness, infill orientation and the number of shell perimeters. Little information is currently available about mechanical properties of parts printed using open-source, low-cost 3D printers. Design/methodology/approach – A computer-aided design model of a tensile test specimen was created, conforming to the ASTM:D638. Experiments were designed, based on a central composite design. A set of 60 specimens, obtained from combinations of selected parameters, was printed on a Rep-Rap Prusa I3 in PLA. Testing was performed using a JJ Instruments – T5002-type tensile testing machine and the load was measured using a load cell of 1,100 N. Findings – This study investigated the main impact of each process parameter on mechanical properties and the effects of interactions. The use of a response surface methodology allowed the proposition of an empirical model which connects process parameters and mechanical properties. Even though results showed a high variability, additional ideas on how to understand the impact of process parameters are suggested in this paper. Originality/value – On the basis of experimental results, it is possible to obtain practical suggestions to set common process parameters in relation to mechanical properties. Experiments discussed in the present paper provide a variety of data and insight regarding the relationship among the main process parameters and the stiffness and strength of fused deposition modeling-printed parts made from PLA. In particular, this paper underlines the shortage in existing literature concerning the impact of process parameters on the elastic modulus and the strain to failure for the PLA. The experimental data produced show a good degree of compliance with analytical formulations and other data found in literature.

scholarly journals Servant leaders, ethical followers? The effect of servant leadership on employee deviance

2019 ◽  
Vol 40 (5) ◽  
pp. 624-646
Author(s):  
Heidi Paesen ◽  
Kristel Wouters ◽  
Jeroen Maesschalck
Keyword(s):  
Servant Leadership ◽  
Protective Effect ◽  
Online Survey ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Situational Factor ◽  
Strengthening Effect ◽  
Content Type ◽  
Employee Deviance ◽  
The Impact

Purpose Leadership is considered to be a crucial situational factor in predicting and explaining employee deviance. The purpose of this paper therefore is to investigate the relationship between servant leadership on the one hand and employee deviance on the other. While previous studies on the impact of servant leadership on employee deviance typically aggregated all its dimensions into a single scale, this study also explores the impact of the various dimensions of servant leadership separately. Design/methodology/approach Data were collected via an online survey in two ministries of the Belgian Federal Government (n=3,445). The analyses were conducted using confirmatory factor analysis and multiple linear and negative binomial regression analysis. Findings The empirical results suggest that the generic servant leadership scale has the expected negative, protective effect on both self-reported and observer-reported employee deviance. As for the dimensions, the authors found that only the “putting subordinates first” dimension had a significant negative, protective effect on both self-reported and observer-reported employee deviance. The dimensions “behaving ethically” and “emotional healing” negatively impacted only observer-reported employee deviance and the dimension “creating value for society” negatively impacted only self-reported employee deviance. Surprisingly, the dimension “empowering” had a significant positive, strengthening effect on both self-reported and observer-reported employee deviance. Originality/value While most research assesses servant leadership’s impact on desirable behaviour, this study is about its impact on employee deviance. Also unlike most previous research, this study looks not only at the overall effect of servant leadership, but also at the impact of the various dimensions of servant leadership separately.

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