Ram Coin Dimpling: Assessment of Modern Dimpling Methods
Issue:
Volume 9, Issue 3, June 2021
Pages:
42-49
Received:
27 July 2021
Accepted:
6 August 2021
Published:
13 August 2021
Abstract: Given the increasing necessity of improving the structural assembly methods especially in the aviation industry; a proper study by comparison of the currently used methods could reveal to be helpful in choosing the right method to achieve one’s manufacturing goals. It could also incite further researches to solve the existing deficiencies in this domain or make more efficient the existing ones. With the above-mentioned motives, this paper is a close look at dimpling methods. This paper will revise the key characteristics of hot dimpling and cold dimpling by experimental results on sheet materials with different properties. Tensile test and shear test were carried out to evaluate the strength of the sheet material after each dimpling method and study diverse failures remarked while doing experiments. The dimples’ status, fatigue and especially radial cracks and hole sizes, is evaluated. We wish to achieve dimples that permit the rivets to sit flush with the surface of the surrounding material and rivet’s head to fit with no defect. Due to the increasing complexities encountered in the manufacturing and assembly of air and space vehicles, missile systems and associated equipment, this research is provided to be used as an enlightenment to dimpling processes; especially ram coin dimpling. The ram coin dimpling method is divided into cold dimpling (room temperature) and hot dimpling (increased temperature). Comparing this research paper to the studies previously done, we found that hot dimpling though requiring a lot more attention proves to be more efficient on thick or brittle sheet materials, where cold dimpling would produce radial cracks.
Abstract: Given the increasing necessity of improving the structural assembly methods especially in the aviation industry; a proper study by comparison of the currently used methods could reveal to be helpful in choosing the right method to achieve one’s manufacturing goals. It could also incite further researches to solve the existing deficiencies in this d...
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Effect of Dreyfus Model of Training on Motor Vehicle Mechanic Work Students’ Skill Acquisition in Technical Colleges in North East, Nigeria
George Nwachukwu Ogbonna,
Abuubaida Abdullahi Shettima,
Victor Ikechukwu Oguejiofor,
Samsun Ikenna Nwaodo,
Kingsley Chimezia Udogu
Issue:
Volume 9, Issue 3, June 2021
Pages:
50-57
Received:
18 April 2021
Accepted:
16 June 2021
Published:
19 August 2021
Abstract: The study was a pre-test, post-test, non-equivalent control group quasi-experimental design. The study was to determine the effect of Dreyfus model of training on Motor Vehicle Mechanic Work students’ skill acquisition in Technical Colleges. Specifically, the study seeks to find out the effect of using; Dreyfus model of training compared to Demonstration method on student’s achievement on suspension system, braking system and student’s interest on Motor Vehicle Mechanic Work Trade. The population for this study comprises of 233 respondents NTC II students of MVMW. The sample size for this study was 43 NTC students selected from the study. Instruments used for data collection were: Auto-mechanics Achievement Test (AAT) with 40 multiple questions, marking scheme answer options (A-D) and Auto-Mechanics Interest Inventory (AMII) with 30 items. Score guide sheet based on four-point rating scale used by teachers or ratter. The Cronbach Alpha Reliability Coefficient of the test instrument was used to determine the reliability coefficient of 0.81, is obtained which were indicates that the instrument was reliable for the study. The data collected was analysed in line with the research questions and hypotheses. The interest inventory was analysed using mean and standard deviation. A mean of 3.50 and above will be considered interested, below that were considered not interested. the mean gain will be used to answer research questions one to four, while Analysis of covariance (ANCOVA) was used to test the null hypotheses at 0.05 level of significance with the use of Statistical Package for Social Sciences SPSS (Vision, 20). The effect was found to be significant, the study revealed that Dreyfus model is effective in enhancing students’ skill acquisition in braking system, the effect was found to be significant, it was found out that Dreyfus model is effective in enhancing students’ skill acquisition in suspension system, the effect was found to be significant. Therefore, the following recommendation are made: Motor vehicle mechanic work teachers should adopt Dreyfus model to improve teaching and learning of auto-mechanic courses, in preparing lesson plans/note, Motor vehicle mechanic work teachers should include Dreyfus model when teaching students in the class. Workshops, seminars and conference should be organized by Ministries of Education/NBTE to enlighten Motor vehicle mechanic work teachers on how to improve their knowledge and skills on the use of Dreyfus mode, and developers should carry out curriculum improvement to capture Dreyfus model for teaching activities and experiences.
Abstract: The study was a pre-test, post-test, non-equivalent control group quasi-experimental design. The study was to determine the effect of Dreyfus model of training on Motor Vehicle Mechanic Work students’ skill acquisition in Technical Colleges. Specifically, the study seeks to find out the effect of using; Dreyfus model of training compared to Demonst...
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