Vidhya Venkat, M. S. Shunmugam
Evaluation of cylindricity and sphericity from form data using Support vector regression

Manufactured components are subjected to measurement in order to verify their conformance to specifications. From the measurement data, approximate functions are established to assess errors on geometry of the components. Misalignment in setting of the components for cylindricity and sphericity measurements leads to certain degree of distortion in the measured data. The size-suppression inherent in these form measurements leads to data representing deviations in microns. Therefore, limacon cylinders and limacoids are respectively used as approximating functions for the evaluation of cylindricity and sphericity errors. In this research, Support Vector Regression has been used to arrive at these functions for minimum zone evaluation.

Joseph Gonsalvis, H. R. Prakash, H. K. Sachidananda
Experimental investigation of power loss in altered tooth sum gearing

Gears are the most efficient power transmission elements. Power loss in transmission is an important parameter which determines the efficiency of the system. The tooth action from the beginning to the end of contact along the path contact consists of slide/ roll motion, while rolling being predominant at the pitch point, sliding takes its share at the begin and end points. The coefficient of friction is higher during approach compared to the recess; therefore power loss in gearing can be regulated by designing gears to maintain tooth action which will lower the power loss. Altering the toothsum of a gear pair working between a specified center distance and module introduces profile shift, which can be used effectively in designing gears for higher efficiency. Unlike other types of gearing the altered tooth-sum gearing provides a greater amount of freedom in using large values of profile shift which is commonly not in use. The alteration in number of teeth can be varied up to ± 4% of tooth-sum. This paper presents about the methods to select the number of teeth to be altered on a tooth-sum and to use the resulting profile shift coefficients to obtain tooth action which lowers the sliding power loss. Few cases of altered tooth-sum gearing are considered for experimental investigations for a tooth-sum of 100 to demonstrate the proprieties of altered tooth-sum gearing. The findings indicate clearly that altered tooth-sum gearing can be employed in designing gears to achieve higher efficiency.

S. Senthilvelan, R. Gnanamoorthy
Influence of carbon fiber reinforcement over the accuracy of injection molded polymer gear

Injection molded polymer based gears are not preferred for precision motion applications due its directional shrinkage behavior. This paper attempts to predict the material shrinkage of unreinforced and carbon fiber reinforced nylon gears and correlate with gear metrological parameters. Fiber alignment along the tooth profile restricts the shrinkage and induces anisotropic shrinkage, which significantly decrease the deviation of involute profile parameter from the design values. Fibers embedded in the molded skin surface increases the gear tooth profile form deviations. Nonalignment of fibers across the gear tooth section increases tooth thickness, tooth-to-tooth spacing and radial runout deviations from design values.

Bhuvnesh Bhardwaj, Vijay Kumar Sharma
Determination of young’s modulus of cantilever beam by digital speckle pattern interferometry

Digital speckle pattern interferometry (DSPI) is becoming more and more popular for deformation analysis and testing due to its non-invasive nature. In the present work, out-of-plane static deformation method is used to determine Young’s modulus (E) of cantilever beam made of Aluminium. A fringe pattern corresponding to deflection of cantilever beam due to point load at its free end was recorded. To improve the measurement accuracy from the fringe pattern, a filtering scheme based on combination of median/wiener and maximum filtering is used. This filtering scheme reduces noise, improves contrast and makes the fringe pattern more distinct. The deflection calculated by using fringe count of out-of- plane static deformation method at the distance of 90.58mm from fixed end is compared with the deflection at the same distance with respect to the corresponding measured value by Mitutoyo dial gauge at the free end. It is found that the values of deflection obtained by both the methods are in good agreement. The Young’s modulus of elasticity was calculated using fringe count, load applied and dimension of the cantilever plate. The value comes to be 69.92 GPa. The Young’s modulus is also determined using UTM and is used to compare with the value calculated by out-of-plane displacement method of DSPI. The Young’s modulus calculated using DSPI and that calculated using UTM are in good agreement.

Yu. V. Chugui, V. S. Bazin, S. V. Kalichkin, V. E. Kalikin, S. N. Makarov, M. F. Stupak, A. G. Verkhogliad, I. A. Vykhristyuk
Automatic laser system for railway contact wire inspection

An optical structured light method and an opto-electronic system for automatic noncontact distant measurements of wear and defects detection for a contact wire electro-supply network are presented. The system industrial prototype can extract the main technological wire parameters, first of all, the remaining height with RMS error down to 0.15 mm and the wire cross-section area with RMS error of 1.5 mm². This information is sufficient for confident decision on operation of contact wire electro-supply network. This method could be applied for automatic wire wear measurement and defects detection for trams, trolleybuses and other electro-supply vehicles.