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Article
Publication date: 11 January 2022

Tushar Sonar, Visvalingam Balasubramanian, Sudersanan Malarvizhi, Thiruvenkatam Venkateswaran and Dhenuvakonda Sivakumar

The primary objective of this investigation is to optimize the constricted arc tungsten inert gas (CA-TIG) welding parameters specifically welding current (WC), arc constriction…

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Abstract

Purpose

The primary objective of this investigation is to optimize the constricted arc tungsten inert gas (CA-TIG) welding parameters specifically welding current (WC), arc constriction current (ACC), ACC frequency (ACCF) and CA traverse speed to maximize the tensile properties of thin Inconel 718 sheets (2 mm thick) using a statistical technique of response surface methodology and desirability function for gas turbine engine applications.

Design/methodology/approach

The four factor – five level central composite design (4 × 5 – CCD) matrix pertaining to the minimum number of experiments was chosen in this investigation for designing the experimental matrix. The techniques of numerical and graphical optimization were used to find the optimal conditions of CA-TIG welding parameters.

Findings

The thin sheets of Inconel 718 (2 mm thick) can be welded successfully using CA-TIG welding process without any defects. The joints welded using optimized conditions of CA-TIG welding parameters showed maximum of 99.20%, 94.45% and 73.5% of base metal tensile strength, yield strength and elongation.

Originality/value

The joints made using optimized CA-TIG welding parameters disclosed 99.20% joint efficiency which is comparatively 20%–30% superior than conventional TIG welding process and comparable to costly electron beam welding and laser beam welding processes. The parametric mathematical equations were designed to predict the tensile properties of Inconel 718 joints accurately with a confidence level of 95% and less than 4.5% error. The mathematical relationships were also developed to predict the tensile properties of joints from the grain size (secondary dendritic arm spacing-SDAS) of fusion zone microstructure.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 5
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 1 December 2022

Dhamothara kannan Thirumalaikkannan, Sivaraj Paramasivam, Balasubramanian Visvalingam, Tushar Sonar and Sathiya Sivaraj

Rotary friction welding (RFW) was used to solve the issues in fusion welding of rod to plate joints of low carbon steel (AISI 1020 steel/AISI 1018 steel) such solidification…

139

Abstract

Purpose

Rotary friction welding (RFW) was used to solve the issues in fusion welding of rod to plate joints of low carbon steel (AISI 1020 steel/AISI 1018 steel) such solidification cracking, wider heat affected zone (HAZ), lower HAZ hardness, high residual stresses and distortion. The main objective of this investigation is to develop parametric mathematic models (PMMs), 3D response surface analysis to predict tensile strength (TS) and weld interface hardness (WIH) of rod to plate joints and correlate microstructure with TS and WIH of rod to plate joints.

Design/methodology/approach

The three-factor x five-level central composite design (CCD) consisting fewer experiments was employed for designing experimental matrix. The tensile and microhardness tests were performed to evaluate mechanical performance of joints. The PMMs of TS and WIH of rod to plate joints were developed using polynomial regression equations incorporating the RFW parameters. The 3D response surfaces were developed using response surface methodology (RSM) to optimize RFW parameters for joining AISI 1020/AISI 1018 rod to plate.

Findings

The joints made using friction pressure/friction time (FRNP/FRNT) of 3.71 MPa/s, forging pressure/forging time (FRGP/FRGT) of 3.71 MPa/s and rotational speed (RTSP) of 19.99 rps exhibited higher TS and WIH of 452 MPa and 252 HV0.5. The PMMs accurately predicted TS and WIH of rod to plate joints at less than 1.5% error and 95% confidence. The RTSP revealed greater effect on TS and WIH of rod to plate joints followed by FRGP/FRGT and FRNP/FRNT. The superior TS and WIH of joints developed using optimized process parameters is correlated to the evolution of finer bainitic microstructure in weld interface due to the dynamic recrystallization of grains ensued by optimum frictional heating and plastic deformation.

Originality/value

The PMMs were developed for predicting TS and WIH of joints. The RFW parameters were optimized to enhance TS and WIH of joints. Low carbon steel rod to plates joints were developed using RFW for automotive applications without fusion welding defects. The microstructural features of low strength and high strength rod to plate joints were correlated to the TS and WIH of rod to plate joints.

Details

Multidiscipline Modeling in Materials and Structures, vol. 19 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 16 October 2023

Nabil Hasan Saleh Al-Kumaim, Marya Samer, Siti Hasnah Hassan, Muhammad Salman Shabbir, Fathey Mohammed and Samer Al-Shami

The purpose of this study is to understand the situation of hotels and tourism industry in Malaysia during and in post Covid-19 and to mitigate indirect damage caused by COVID-19…

649

Abstract

Purpose

The purpose of this study is to understand the situation of hotels and tourism industry in Malaysia during and in post Covid-19 and to mitigate indirect damage caused by COVID-19 to the hotel business and tourism industry by examining the factors that have an influence on hotel’s customer satisfaction rating and revisit intention through an integration of service quality (SERVQUAL) framework and expectation-confirmation theory (ECT).

Design/methodology/approach

The SERVQUAL and ECT were considered the underpinning theoretical models but are integrated and extended by including a few additional variables. Data were collected from 458 respondents of travelers and hotel customers in Malaysia and analysed by applying partial least squares structural equation model technique.

Findings

The empirical results established that significant positive relationships exist between the three newly emerged independent variables (IVs), namely, hygienic practice, greenness of service and digitalization and hotel customer satisfaction towards hotel revisit intention, and only two variables from SERVQUAL, namely, reliability and assurance, have a significant relationship with hotel customer satisfaction towards hotel revisit intention. The results reveal that customer satisfaction has significant direct effect between above-mentioned IVs and customers revisit intention.

Research limitations/implications

The use of purposeful sampling method in only one country might limit the generalizability of the results. Future research should be planned to duplicate the current study using a sizable sample of participants from multiple countries and include other related factors related to the pandemic phenomena such as safety, hotel location and health value offered.

Practical implications

Theoretical findings imply that service quality is a dynamic theory that should be examined continuously to achieve sustainable and resilient performance in today’s competitive business environment, as some modifications inevitably occur over time and new factors could be emerged. Regarding practical implications, study findings proved the great significance of assurance, reliability, digitalization, greenness and hygienic practices on customer satisfaction towards intention to revisit to hotel. Therefore, it is critical for hotel management to retain hotel business industry in a way that fits and matches customer’s health protection, meets customer’s newly prompted expectations and needs and ensures resilience during unsettled times.

Originality/value

This study is unique as the newly emerged variables are included in the research framework, and thus it helps to close the literature gap by introducing an integrated SERVQUAL and ECT theoretical model, which rarely performs in this context and can be replicated or extended with validated scales. This study contributes to enhancing hotel and tourism sustainable service quality performance to achieve myriad economic and health values.

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