Bioresorbable Composites and Implant

Different biomaterials in the form of ceramics, metal alloys, composites, glasses, polymers, etc. have gained wide-range acceptance in the realm of medical sciences. Bioimplants from such biomaterials have been constructed and used widely for different clinical applications. With the continual progress, biomaterials that may be resorbed inside the body have been developed. These have done away with the major challenge of removal of an implant after it has served its intended function. Important factors are taken into consideration in design and development of implants from such biomaterials are mechanical properties, degradation rate, surface modification, rate of corrosion, biocompatibility, and non-toxicity. Given the importance of such materials in clinical applications, the chapter presents an overview of the bioresorable composites and their implants. The related properties and the functions served have been outlined briefly. Further, the challenges associated and the remedies to overcome them have also been delineated.

A Systematic Survey of the Realm of Biomechanics

The area of biomechanics is challenging and broad as it involves multidisciplinary concepts of engineering together with functional knowledge of biosciences. The area is rapidly evolving and new additions to it are being made daily. A survey that may help a beginner to have a general look on the broader aspects of the sub-domains of biomechanics is not available. The chapter aims to overview the realm of biomechanics and provide an introduction to various areas with mention to researches carried out. A broad survey of various areas of biomechanics from a mechanical engineer's perspective is reported in this chapter. Prominent areas like biomechanics of human motion; bone and joint biomechanics; biomechanics of spine; biomechanics of head, shoulder, and muscles; biomechanical analysis of heart and lungs; biomechanical analysis of arteries and veins; and MEMS in biomechanics are explored. Though it is difficult to include all the developments relevant to the above areas, the authors have focused primarily on a few prominent studies made in the last two decades in various domains.

Optimization Methods for Minimizing Induced Stress During Tensile Testing of Prosthetic Composite Materials

The application of composite materials for prosthetic applications is the norm in recent times. Accurately characterizing the principal stresses during tensile testing is therefore essential. The low transverse compressive strength of most composite materials limits high clamping forces during tensile testing. Tabs are consequently critical for cushioning against grip pressure and surface damage. However, tabs tend to introduce induced stress concentrations. In this chapter, the induced stress concentrations are minimized via the optimization of tab design configurations. Stress concentration obtained via finite element analysis were used to develop a full factorial design for statistical analysis and compared with a Taguchi, Taguchi-multi response and Taguchi-genetic algorithm optimizations. It was established that to minimize the stress concentrations, low values of tab stiffness, thickness, and taper angle were required while the adhesive thickness was increased. The Taguchi and hybrid approaches were efficient and reduced the number of simulations from 32 to 8 (75% reduction).

Modeling and Numerical Analysis of Advanced Machining for Orthotic Components

Electrochemical micromachining plays a vital role in the advanced machining domain. Particularly, it helps the medical industry in machining micro-level devices in hardened materials. Though it is maintaining a very small inter-electrode gap during machining, it is required to understand suitable machining parameters before machining. These parameters can be achieved by proper modeling and simulation. In this chapter, a model for flow analysis of electrolytes in inter-electrode gaps is designed to obtain optimal process parameters for machining. The geometric model used in this simulation consists of cylindrical workpiece, an inlet allowing the flow of sodium nitrate solution as electrolyte to the machining zone, and a cylindrical tool with a flat end. Electrolytic flow simulation is incorporated using computational fluid dynamics by ANSYS–CFX 15.0 for finding pressure variation, streamline velocity pattern, turbulent energy, and temperature contour in IEG. According to the CFD analysis, the passivation effect, stagnation effect, pressure, and temperature zone are studied.

A Review on Materials for Orthotic Devices

The recent use of fiber-reinforced composites as bio-material in fabrication of orthoses have accelerated the research in finding the most compatible combinations of bio-polymeric composites. The strength, flexibility, biological compatibility, durability, and fatigue strength can be easily altered considering different combinations of polymers and their reinforced structures. In this chapter, a review of the presently used polymeric composites as orthotic materials, their properties, and their applications based on their availability for common people, for a variety of specialized functions, and for the best quality and compatibility factor were discussed. The common orthotic devices mainly used on patients to support weak joints or limbs, materials used, and processing techniques were discussed. Characterization tests for polyethylene composites performed for material properties like ultimate tensile and bending strength, elastic modulus, thermal degradation properties, and surface resistance were discussed, which validates the usability of polyethylene in orthotic fabrication.

Experimental Investigation on ECMM With Nimonic 75 Alloy for Prosthetic Component

Electrochemical micromachining is an advanced technology of recent trends of machining of hard and electrically conductive materials in micrometer and sub-micrometer scale. This manufacturing technique finds application in many technologically demanding industries: locomotive, biomedical, electronics, etc. However, due to very small inter-electrode gap, there is some limitation in using this machining process. This chapter aims at developing an optimized model for flow analysis of electrolyte in inter-electrode gap to obtain optimal process parameter for machining. Experimentation has been done to associate the findings of optimized output in ECMM such as material removal rate (MRR), overcut, and depth. Influence of voltage, feed rate, concentration, pulse on/pulse off ratio, and IEG investigated and finally optimized using response surface method. The effect of the process parameters are also analyzed using ANOVA.

Design of a Prosthetic Ankle Complex

Nature has, over a large span of geological time, engineered near perfect solutions to most problems humans face today. Motion of the limbs is one such area, and the cutting edge in the development of effective prostheses is biomimetics. Limb prostheses have been used by mankind for the better part of known history, and most of the technology currently available in prosthetics is not exclusively new. However, modern prosthetics either are uncomfortable—and the lack of flexion affects the gait of the patient—or too expensive for a large segment of the populace. This chapter seeks to study the mimicry of physiological systems through the design for an ankle prosthesis that includes a passive damper and mimics the shape and behavior of the natural ankle joint.

Correction of Artifacts and Optimization of Atomic Force Microscopy Imaging

Acquisition of experimental data from atomic force microscopy (AFM) sometimes has artefacts that distort the information contained in the image. Such artefacts can be very delirious especially for sensitive applications such as in biomedical and microelectronics. This chapter illustrates the correction of the artefacts resulting from tapping mode imaging. It also shows the application of Taguchi optimization technique for reducing artefacts during AFM imaging. Using AFM images of Al films, Fourier filtering is illustrated as a useful technique for correcting the artefacts. Taguchi optimization is shown to determine the optimal scan rate, scan size, integral and proportional gains in minimizing the size and number of artefacts at the imaging stage. The correction technique is shown to improve the morphological information of the AFM images while the Taguchi method is effective for determining the best imaging conditions for AFM analysis.

A Brief History of Prosthetics and Orthotics of the Lower Body and Their Types

Prosthetics and orthotics are items taken for granted in today's day and age. However, this has not always been the case. The history of these everyday items is long and very colorful. In this chapter, the authors shed light on the history and development of prosthetics and orthotics of the lower body in order to better understand the current state of the art in the fields. A historical perspective is provided followed by enumeration of the types of devices and techniques available without going into the form and function of individual products.

Scaffolds and Tissue Engineering Applications by 3D Bio-Printing Process

3D bio-printing is a revolutionary manufacturing process that is widely used in medical fields especially in preparing bone scaffolds and tissue engineering. With the help of new biocompatible material like polymers, bio-gels, ceramics, this technology has created a new site in advanced tissue engineering and scaffolds manufacturing area. Another important thing is that, with the use of CAD file software, any complex design can be prepared (i.e., this technology does not have any limited sites). But here it is very much essential to study and analyze machine printability characteristics, cross-linking time and biocompatibility of printing objects as well as bio-ink. However, mechanical properties like shear thinning, mechanical elasticity are also required. In this chapter, different types of scaffold-preparing methods and the bio-printing process are discussed, which are used in scaffold and tissue engineering.