Whole Field Analysis of Asymmetric Helical Gear Using Photo Stress Method and FEA Method

Objectives: To carry out dynamic state analysis of asymmetrical helical gears for contact stresses using photo stress technique and suitable finite element software. Methods: Currently the Hertz contact stress equation is used to calculate the contact stress which is based on certain speculations. The value of load transmitted by a gear may be known but whether it is taken by a single or more pairs of teeth are based on some assumptions and stresses thus calculated may not be true stresses. To get precise evaluation of stress field in gear tooth it is decided to carry out experimental work on asymmetric helical gear in actual working condition. The photo stress method not only provide magnitude of stress but also gives idea about stress distribution in gear. Finite element method is used for asymmetrical helical gear to validate experimental results. Findings: The stress values obtained by photostress method and FEA method has minimum error of 2.17% and maximum of 8.89% respectively. The error values are less than 10% and within the limit. We can observe close agreement between these two methods. Novelty: This study has provided a more accurate result than theoretical method of stress calculation. Photostress analysis method is one of the best test methods for evaluation of contact stress of asymmetric helical gear with different torque condition in actual working that is dynamic condition. Maximum error of 8.89% has been found with photostress method. Keywords: Asymmetric Gears; Contact Stress; Experimental Method; Reflection Polariscope; PhotoStress; Finite Element Analysis