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Semicircular canal plays an important role in sensing of human body orientation. Cupula is the system in semicircular canal responsible for sensing rotational head movements. It is excited by the flow of endolymph caused due to inertia of head movement. There are various disorders related to semicircular canal, the most common disorder is Benign Paroxysmal Positional Vertigo (BPPV). Present work focuses on determination of response of cupula due to endolymph flow in the horizontal semicircular canal. Variation of pressure generated on cupula by endolymph for different rotational velocity of head is studied and reported. Response of cupula with appropriate boundary conditions is extracted. Results obtained open up new area of research in better understanding the behavior of cupula with endolymph flow. It may aid in the betterment of curing BPPV.

A free vibration analysis is carried out on a discretized Fokker aircraft with an integrated bio-dynamic pilot model. It is an attempt to study the dynamic behavior of bio-dynamic pilot model, when the vibration is induced in aircraft. The system is assumed to have an eleven degree-of-freedom including bouncing motion of tyres, fuselage, seating system and pilot’s head along with angular pitching and rolling of fuselage. A robust model is developed using both MatLab Simulink and MSC Adams. System parameters are borrowed from the earlier reported literature of the present authors. Simulation is carried out for various initial input conditions. Responses of fuselage and pilot’s head are reported for initial displacement considered at nose landing tyre. Natural frequencies of the system are generated and compared with earlier reported results. A good agreement is noticed among the results obtained via all the three of analysis approaches.

This work deals with the formulation of mathematical model for a discretized aircraft with combined seated biodynamic pilot model. The developed model provides scope for exploring the dynamic characteristics of the aircraft system and pilot under various runway operations and landing impacts. Modal analysis approach is used to obtain the free vibration characteristics of multi degrees-of-freedom system. The obtained results like natural frequencies, mode shapes and undamped response curves are reported.

Persistent exposure to whole body vibrations is the fundamental cause for lower back pain and disc degeneration. With an increasing amount of population exposed to whole body vibrations, a significant number of people experience fatal spine diseases. Substantial research is carried out to reduce the risk of spinal injuries. The dynamic characteristics of the cervical, thoracic and lumbar (CTL) region are studied extensively as individual sections of the spine. Few studies have focused on the CTL spine as an assembly of the three segments. In the present work, an authentic three dimensional geometrical model of the cervical, thoracic and lumbar spine is developed in mimics considering its natural curvature and the intervertebral discs are modeled in Design modeler. The natural frequency and mode shapes of the CTL spine are extracted using free vibration modal analysis considering 4.5 kg point mass on C1 vertebra and distributed mass of 40 kg on the CTL spine in Ansys Workbench. Six natural frequencies and their corresponding vibration modes are obtained from the finite element model. The results of this study aims to provide a reliable model for further biomechanical analysis and ergonomics.

Cancer is one of the leading causes of death in the world. Breast cancer is the most common form of cancer among women and is responsible for 15 % of all cancer related deaths. Though there are significant advancements in cancer treatment strategies, clinical tumour treatment methods currently employed are often accompanied by severe side effects as they induce damage to the normal cells along with the cancer cells. The alterations in the biophysical and biomechanical properties of a cell as it undergoes transformation from a normal to cancerous cell results in changes in its dynamic characteristics. These changes can be utilised to induce selective cytotoxicity of tumour cells. In the present study, two simulation models (homogenous and non-homogenous) of normal (MCF-10A) and cancerous (MCF-7) breast cells are developed. A finite element approach using Ansys is adopted to investigate the variation in dynamic characteristics of the cells using the two modelling approaches. Results indicate that the natural frequencies of cells modelled as a homogenous system is greater than that of cells whose sub-cellular material properties are considered for analysis. A comparison of the first four natural frequencies using the two modelling approaches for both MCF-10A and MCF-7 cells are illustrated and the corresponding mode shapes reported. A plot highlighting the variation in the natural frequencies of MCF-10A and MCF-7 using the two modelling approaches is presented.

Any dysfunction of vestibular system leads to various diseases, the most common among them is Benign Paroxysmal Positional Vertigo (BPPV). BPPV is most found in elderly people causing vertigo/dizziness which leads to fall and serious injuries. The primary system in inner ear helping in human body balancing and postural adjustment is the cupula. Cupulolithiasis is a type of BPPV caused when otoconia get settles on the cupula. In the present work, a three-dimensional model of cupula and otoconia particle is modelled. A free vibration modal analysis is carried out on the cupula with and without otoconia particle to extract the natural frequency and mode shapes. Change in natural frequency of the cupula due to presence of otoconia particle is presented. Present work has a future scope involving fluid solid interaction (FSI) and extracting response of the cupula incorporating damping to obtain complete dynamic characteristics of cupula. The extracted results help in future investigation of new therapeutical solution to treat BPPV.

Parallel manipulator is one of the areas of research extensively studied by many researchers from past 4-5 decades. Unlike their serial counterparts, parallel manipulators exhibit higher rigidity and controllability when operating at higher speeds. These attributes lead to their application in various fields such as machine tools, simulators and positioning systems. Present work is proposing a modified reconfigurable Dodecapod parallel manipulator. 3D model of the proposed manipulator is successfully developed and kinematics analysis is carried out. Re-configurable sliders are provided to vary the workspace as required. A few illustrative examples are demonstrated for various locations of slider, showing changes in workspace. The novelty of the present manipulator overcomes the workspace limitations of the general Stewart Gough manipulator. Present modified Dodecapod parallel manipulator is capable of improving local kinematic performance.

The landing gear plays a very important role during landing by absorbing the high impact energy of the aircraft. The main landing gear absorbs the bulk of the load to reduce the load experienced by both the aircraft fuselage and the nose landing gear. In this paper, a mathematical approach is used to extract the dynamic characteristics of the system. A two-degree of freedom mathematical model of the main landing gear is developed. This model is used to derive the dynamic equations of the landing gear system and to study the behaviour of main landing gear during main gear and nose gear touchdown conditions. The non-linear stiffness and damping co-efficient in an Oleo-Pneumatic shock absorber are integrated into the system to achieve a more accurate response of the system. The response of this system is established by adopting a complex modal analysis approach to account for the non-classical damping exhibited by the system. The obtained spring force, damping force and responses are reported. This work provides an alternative approach using complex modal analysis to obtain results for complex systems exhibiting non-linear characteristics.

Mechanical stress and fracture analysis of the human lumbar intervertebral discs are important in assessing disorders related to lower back pain and ageing. Finite element modelling and simulation approaches assist in easier prediction of the disc behaviour under different load conditions. The causes of mechanical failure and morphological changes still remain partially speculative. The present study addresses the issue by developing a finite element model of an L3-L4 lumbar intervertebral disc subjected to different axial compressive loadings. The morphological deformations and stress concentration regions within the disc are analyzed and reported. A mathematical relation is established to estimate the breaking strength of an L3-L4 intervertebral disc, thus indicating the risk of disc failure based on the applied load.

Cell dynamics is one of the most investigated areas under the field of biomechanics. Scaling plays a crucial role in determining the dynamic characteristics of biological systems. In the present investigation, cuboidal and cylindrical models of different scales are analysed to depict the dependence of natural frequency on the scaling factors. Three approaches, namely lumped mass system, finite element model (FEM) and numerical approach using Ansys are used to determine the fundamental natural frequencies. Different scaling factors, namely nano, micro (original size), millimeter and meter are considered for the analysis. The results indicate that the natural frequency varies inversely with the size of the cell by the same factor. A simple mathematical relation is derived to support this claim. Results are illustrated with numerical examples and corresponding mode shapes are reported.

Bone is a dynamic connective tissue which adjusts to load variations through continuous bone remodeling, which occurs due to the dynamic behavior of bone cells. Many researchers made attempts in obtaining the dynamic characteristics of osteoblasts and its role in bone remodeling cycle. While making an effort to understand the effects of mechanical stimuli on the osteoblast, certain ambiguity is observed in the past literatures. This paper is to demonstrate the dynamics of osteoblast cells and exhibition of different natural frequencies during its life cycle. Osteoblast is modeled as a frustum of a sphere, considering it as a continuum model. The three prominent parts of an osteoblast, i.e., membrane, cytoplasm and nucleus are considered with reported material properties. Lifespan of an active osteoblast during bone remodeling cycle is considered as 90 days and progressive osteoblast stages are analysed using Ansys. First ten natural frequencies and mode shapes are extracted for nine stages and reported. It is observed that the natural frequencies of a micron sized osteoblast are in the range of kHz. A mathematical relation for the lifespan of an active osteoblast is obtained using curve fitting for fundamental natural frequencies. The natural frequency for exciting an active osteoblast on each particular day during its lifespan can be derived from the relation. This relation can serve as a guiding tool in bioengineering for in vitro bone cell culturing. Results also throw light on the excitation frequency and natural frequency of an osteoblast for proper analysis purpose. The different modes of vibration of osteoblast is identified and reported.

Present work establishes a new formulation to determine the dynamic characteristics of a cracked beam, where the change in second moment of area is considered. The present formulation considers the shift in the neutral axis of the cracked beam-element, which has been ignored previously. Consequently, an in-depth analysis is conducted to understand the effectiveness of this new approach. The results obtained shows a promising scope for the adoption of the updated formulation for various cross-sections and future research work.

Structural analysis is mainly concerned with predicting the behaviour of a structure when subjected to any external excitation. Dynamic analysis of simple structures can be carried out using finite element analysis on various computing platforms such as MatLab. In the case of industrial applications, dynamic analysis is mainly carried out using simulations on softwares such as Ansys. The present paper compares mathematical and simulation analysis of cracked beam and the dynamic behaviour with respect to mode shape and crack position is reported.