Pavani Udatha

Bio: Pavani Udatha is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Composite number & Specific modulus. The author has an hindex of 1, co-authored 2 publications receiving 6 citations. Previous affiliations of Pavani Udatha include Indian Institutes of Information Technology.

The effect of CNT to enhance the dynamic properties of hybrid composite tube shafts

Abstract: Composite materials are having good dynamic properties, specific strength, and specific stiffness. The analytical formulations for dynamic analysis of composite tube shafts are mainly equivalent mo...

Dynamic Analysis of Three-Dimensional Composite Tube Shafts

Abstract: Three-dimensional (3D) composites have good delamination resistance along with high specific stiffness and high specific strength. Composite tube shafts are modeled with different reinforcement architecture such as multi-axial, stitched, knitted, braided, orthogonal woven, interlock and z-pinned. The in-plane elastic properties at different fiber volume fractions of these composites are obtained from the literature. 3D composite tube shafts are modeled with length: 1 m, internal radius: 25 mm and thickness: 4 mm using modified equivalent modulus beam theory formulation. Modal analysis is carried out, and bending natural frequencies are calculated for different 3D composite tube shafts with E-glass, carbon and kevlar fibers and epoxy as matrix materials. The natural frequency reduces with through thickness reinforcement for orthogonal, knitted, z-pinned and stitched composites. Braided composites tube shafts have higher natural frequencies compared to that of other types.

Timoshenko nonlocal strain gradient nanobeams: Variational consistency, exact solutions and carbon nanotube Young moduli

Abstract: Carbon nanotubes (CNTs) are principal constituents of nanocomposites and nano-systems. CNT size-dependent response assessment is therefore a topic of current interest in Mechanics of Advanc...

Timoshenko nonlocal strain gradient nanobeams: Variational consistency, exact solutions and carbon nanotube Young moduli

Abstract: Carbon nanotubes (CNTs) are principal constituents of nanocomposites and nano-systems. CNT size-dependent response assessment is therefore a topic of current interest in Mechanics of Advanced Materials and Structures. CNTs are modeled here by a variationally consistent nonlocal strain gradient approach for Timoshenko nano-beams, extending the treatment in [Int. J. Eng. Science 143 (2019) 73-91] confined to slender structures. Scale effects are described by integral convolutions, conveniently replaced with differential and boundary nonlocal laws. The theoretical predictions, exploited to analytically estimate the reduced Young elastic modulus of CNTs, are validated by molecular dynamics simulations.

Temperature-Frequency-Dependent Viscoelastic Properties of Neat Epoxy and Fiber Reinforced Polymer Composites: Experimental Characterization and Theoretical Predictions.

Abstract: In general, aerospace structures manufactured using fiber reinforced polymer composites are exposed to fluctuating temperatures and subjected to cyclic loading during their service life. Therefore, studying the temperature-frequency dependent properties of composites for different fiber orientations is essential. However, such experiments are expensive, time-consuming and labor-intensive while theoretical models minimize these issues, but temperature-frequency-dependent viscoelastic models for predicting the full-range of the storage and loss moduli curves of composites are limited. In this study, the dynamic mechanical properties of a neat epoxy resin, unidirectional ([0°]6, [45°]6 and [90°]6), symmetric angle-ply [+45°/−45°/+45°]s and quasi-isotropic [±45°/0°/90°]s carbon/epoxy and glass/epoxy composite panels were investigated. Experiments were performed from room temperature (approximately 35 °C) to 160 °C at five different frequencies (1, 10, 20, 33 and 50 Hz). Two parameter viscoelastic models as function of temperature and frequency were used, and their applicability in predicting the storage and loss moduli for the entire region of the temperature curve is shown. The storage modulus values were compared and validated against the static flexural modulus values coupled with scanning electron microscopy analysis. The flexural and storage moduli values were found to be higher for [0°]6 carbon/epoxy composites, while the activation energy values were found to be higher in the case of [+45°/−45°/+45°]s carbon/epoxy composites compared with epoxy resin and other laminates in different orientations. The predicted results were in reasonably good agreement with the experiments. Both experimental and modeling approaches used in this study are highly valuable for designing aerospace composites for harsh in-service loading conditions.

Effect of nanoparticles loading on free vibration response of epoxy and filament winding basalt/epoxy and E-glass/epoxy composite tubes: experimental, analytical and numerical investigations

Abstract: In recent times, basalt fiber reinforced polymer (BFRP) nanocomposites is being increasingly used in aerospace applications such as wing and fuselage structures of the aircraft and outer casings of the rocket, automobile engine drive shafts and fuel tanks in the oil and gas industries, which fills the gap between carbon and E-glass fiber reinforced polymer nanocomposites. These structures are subjected to vibrations and exposed to different temperatures in various places during their service life. However, the comparison of vibration response of silica particles reinforced basalt/epoxy and glass/epoxy nanocomposite tubes in all three approaches, namely, experimental, analytical and numerical (Finite Element Modeling), have not found elsewhere. Analytical and numerical approaches minimize time, manpower and cost. Therefore, investigating the vibration response of different weight contents of these FRP nanocomposite tubes is novel and essential. Hence, in this study, the vibration response of silica nanoparticles reinforced epoxy, basalt/epoxy and E-glass/epoxy composites with different weight contents (0, 0.5, 1 and 1.5 %) were investigated. The vibration tests were performed at three different boundary conditions such as cantilever, simply supported and fixed-fixed. The first three modes of vibration were considered for analysis. Besides, the heat deflection temperature and the hardness properties were also studied. The results indicate that the natural frequencies were higher for the fixed-fixed case and the damping parameters were higher for the simply supported case. Vibration properties, heat deflection temperature and hardness values were found to be higher in fiber-reinforced nanocomposites than those of epoxy nanocomposites. The data presented in this study will be useful to generate the numerical models for the ground vibration test (GVT).

Fundamental frequency analysis of a thermally loaded corroded exponentially graded rotor bearing system

Abstract: Corrosion is an unintentional degradation of a material, which transpires due to harsh environmental conditions. It is a surface phenomenon that results in loss of material, which affects the dynam...