Ramamurti

Bio: Ramamurti is an academic researcher. The author has contributed to research in topics: Computer Aided Design. The author has an hindex of 1, co-authored 1 publications receiving 10 citations.

Coupled free vibration characteristics of rotating tuned bladed disk systems

Abstract: A detailed qualitative study is presented of the coupled free vibration characteristics of rotating turbomachinery bladed disk systems having useful ranges of geometric parameters. The analysis is carried out by using a three noded triangular shell element having six degrees of freedom per node together with the cyclic symmetric nature of the problem. The blade and disk attachment is established by a set of constraint equations obtained by the Love-Kirchhoff hypothesis. The effects of rotation are included by using a stress smoothing technique while computing the geometric stiffness matrix. The contributions from membrane behaviour and transverse shear are included. The severely coupled systems are identified and an exhaustive parametric study is carried out for these systems to predict the influence of stagger and twist on natural frequencies for stationary as well as rotating systems. An assessment of Southwell's coefficients for these systems is made. Theoretical results agree closely with available experimental results.

Technical Note: Static stress analysis of a composite bevel gear using a three-dimensional finite element method

Abstract: The possibility of using composite materials for power transmission spur gear, from a static strength point of view, have been proved by the authors in their previous study. In this present work an attempt has been made to study the behaviour of composite bevel gear from a static load point of view using a three-dimensional finite element method. The performance of two composite material bevel gears are presented and compared with a carbon steel gear. From a static strength point of view a glass epoxy bevel gear is slightly closer to a carbon steel bevel gear than a boron/epoxy bevel gear; but from a displacement point of view glass/epoxy deviates from that of carbon steel much more than boron/epoxy, unlike the case of a composite spur gear, where boron/epoxy was better both from strength and displacement points of view. Hence from the results it is concluded that composite materials such as boron/epoxy can be very much thought of as a material for power transmission bevel gears.

Static and dynamic analysis of spur and bevel gears using FEM

Abstract: This paper presents the findings of three-dimensional stress analysis of spur and bevel gear teeth by finite element method using cyclic symmetry concept. The displacement of a tooth is computed for each Fourier harmonic component of the contact line load and all the components are added to obtain the total displacement. This displacement is used in the calculation of static stress in the teeth. The natural frequencies and mode shapes are obtained using the submatrices elimination scheme.

Residual stress analysis in weldments

Abstract: Residual stresses caused by welding may be of the order of the yield strength This study aims at estimating these residual stresses through a blend of experimental and theoretical approaches The factors which affect residual stress build up are many, so it is difficult to completely model thermal-elasto-plastic deformation due to welding To simplify the analysis rotational symmetry in the case of pipes and plane strain assumption in the case of thick weldments are made These assumptions need not be always true In the present approach three-dimensional nature of the problem is preserved It is validated using some standard test problems The developed method is applied to some practical cases and the results are presented

Design aspects and parametric study of 3-roll heavy-duty plate-bending machines

Abstract: The fabricated stands of a three-roll heavy duty plate bending machine under load have been studied and a parametric study has been performed on them. The two machines analyzed are capable of cold rolling 14 and 40 mm thick plates. The FEM was used to study the static response of the stands when the machine is in operation, and three-noded triangular plate elements were used for this purpose. The response was computed for the worst case of loading. Cholesky's method in conjunction with the skyline approach was used to study the behaviour of the stand by solving the large-size problem. The objective of the parametric study was to evaluate the performance of the machine stands in relation to various design- or structural-modification and arrive at a satisfactory design.