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By virtue of its high strength-to-weight ratio, preserving its toughness and other mechanical strength properties at high temperature, low wear, and corrosion rates even in eroding environment, and non-reactivity with human body fluid, the titanium α-β alloy Ti-6Al-4V is a supreme material for producing responsible machine parts. However, machining of such and other Ti-alloy based materials is difficult especially due to lower thermal conductivity, unprecedented high heat generation in cutting zone, chemical reactivity of Ti molecules with cutting tool materials (producing built-up edge), further to notoriously low tool life, low molecular density, and poor surface integrity sustained during machining. Development of optimum machining regimes is, hence, important to reduce machining time and consequently the production cost while maintaining product quality and surface integrity. A series of real-life machining investigations, using coated and uncoated carbide inserts, have been carried out to characterise the optimum ranges of individual cutting parameters (v, f, d) with respect of obtained surface roughness (Ra). While machining literature generally focuses on varying specific parameters keeping other parameter constant to characterise the impact of cutting parameters on surface roughness, we in this article process the machining data using machine learning (ML) approaches (Support Vector Machine, Random Forest, and Deep Learning) to characterise surface roughness with respect to varying all three cutting parameters together. Thus, this work makes an important contribution to the current machining literature. The achieved outcomes will facilitate sustainability, economic efficiencies and machining quality in future research and the manufacturing process of Ti alloy products.

Resistance spot welding is one of the commonly used structural joining processes in sheet metal structures. This paper presents the study of vibration characteristics of a spot-welded sheet metal coupon with a simple finite element model. The finite element spot weld nugget was modelled with Spider Configuration (SC) using commercial finite element code ABAQUS. Analytically the spot welded sheet metal coupon was modeled as a free–free Euler Bernoulli beam. Comparison was made for both natural frequencies and mode shapes of the first three bending modes between finite element model and analytical model. It was found that the simple finite element model was able to predict the spot weld joint vibration characteristics with a minimum of 0.35% and a maximum of 7.3% error.

The PWRI is a type of passive isolation system which is commonly used as shock and vibration isolation system especially applied in lightweight equipment and electronic devices. The PWRI can provide isolation in all direction. It can be flexible in any direction and in all three planes which depends on its stiffness. An experimental study of the lateral stiffness of Polycal Wire Rope Isolators (PWRI) is presented in this paper. It also studied effect of variations in height and width of PWRI on its static stiffnesses. Suitable experimental setup was designed and manufactured to meet the test conditions. The results show that their elastic stiffnesses for lateral loading conditions are highly influenced by their geometric dimensions. It is found that their compressive stiffness reduced by 56% for an increment of 25% in their height to width ratio. Therefore, the stiffness of PWRI can be fine-tuned by controlling their dimensions according to the requirements of the application.

This paper presents the study on interaction behaviour of spinnable carbon nanotubes by the peel test technique. Spinnable nanotube webs are used as macro scale experimental specimens to determine the mixed mode interaction behaviour between them. Numerical simulations are conducted to determine and compare the interfacial fracture energy of the interfaces in different orientations peeled at the same peel angle. The numerical model simulates the Van der Waals energy between nanotube webs through implementation of a cohesive law. The peeling process is simulated by considering a failure criterion based on continuum damage mechanics. It is shown that the interfacial energy varied with the orientation angle and the peel angle. Interfacial energy for parallel nanotube configuration is much higher than the crossed nanotube configuration. Increase in peel angle reduces the phase angle magnitudes so that the loading condition transforms from mode – II to mode – I resulting into reduction of the forces required to detach spinnable nanotubes. Hence, this study explores the spinnable nanotube interaction mechanics through which slippage may easily occur among them. Thus, the reason behind nanotube yarn failure before reaching large macroscopic stresses is better understood even though individual spinnable nanotube found to be very strong.

This paper presents results of peel tests with spinnable carbon nanotube webs. Peel tests were performed to study the effect of orientation angles on interface energies between nanotubes. In absence of any binding agent the interface energy represents the Van Der Waals energies between the interacting nanotubes. Therefore, the effect of the orientations on Van Der Waals energies between carbon nanotubes is obtained through the peel test. It is shown that the energy for crossed nanotubes at 90° angle is lower than the energy for parallel nanotubes at 0° angle. This experimental observation was validated by hypothetical theoretical calculations.

Carbon nanotubes are innovative materials with high potential for applications in various industries. However, it is very hard to perform direct experimentation to characterise their mechanical behaviour due to their dimensional constraints. There is wide scatter in the re- ported mechanical strength of individual carbon nanotubes in the literature. Nevertheless, theoretically it is very well established that individually they are amongst the strongest materials so far. However, this strength has yet to transfer to macro scale structures such as carbon nanotube yarns. Individual nanotube has 100 GPa of strength with 1 TPa of modulus of elasticity. But nanotube yarns have reached so far 1.5 GPa of strength. To address the issue of this huge differences in strengths in different structural scales of same material, this thesis embarks on logical step wise investigation of strength distribution and interaction properties of spinnable carbon nanotubes. First, to address the scattering strength issue, this thesis undertake extensive experi- mental investigations utilizing the newly developed nano tensile stage to test the individ- ual carbon nanotubes under uni axial tensile load inside a Scanning Electron Microscope (SEM). It was shown that the strength distribution of spinnable nanotubes depends on the geometric features of the specimen such as the number of broken walls. It increase with the higher numbers of broken walls. However, the probability of getting all the walls of a nanotube broken without any external aid or modification is extremely low. To improve this probability and to enhance their strength, the effect of post synthesis treatments such as gamma irradiation technique is investigated. It is shown that the irradiation doses and environment have influence on strength of spinnable carbon nanotubes. The interaction among the carbon nanotubes has been investigated through macro scale peel tests. It was found that the orientation angle of the nanotubes with respect to each other has profound influence on their interaction characteristics. Simulation of this peeling mechanics revealed that nanotube interface undergo mode transformation which assisted the production of their macro scale constructs. As a result of the findings of this research, it would enhance the understanding of spinnable carbon nanotube characteristics.

The objective of this study is to identify the mechanics of machining at nano scale on single crystal Cu with (100), (110) and (111) crystallographic orientations. A nano indenter equipped with a nano scratching attachment was used for machining operations and in situ observation of a nano scale groove. As a machining parameter, the depth of cut was varied in this study. Both elastic and plastic deformations were significant during machining. The plastic deformation was responsible for causing the ploughing and cutting mechanisms to produce the nano scale groove. The presence of the ploughing and cutting g mechanisms was determined based on the pile up volume and the cutting volume respectively.

Individual multi walled Carbon Nanotubes (CNTs) exhibit exceptional strength and stiffness. However, large scale constructs of directly spinnable CNTs (such as yarns) has reached only a few percent of their potential. To improve their performances in such scale, it is important to understand the stress-strain characteristics and failure modes of individual CNTs. This paper reports the experimental tensile strength of spinnable multiwalled carbon nanotubes (MWNT). These experiments were conducted using a nano tensile testing stage inside Scanning Electron Microscope (SEM) chamber. An Atomic Force Microscope (AFM) tip with known force constant was used as a nano manipulator and as s force transducer to measure the desired mechanical properties. Transmission Electron Microscope (TEM) images were used to accurately measure the diameter of CNT samples. The fracture strength was calculated using the determined applied force and the diameter of the CNT. Fracture strength in relations to number of failed walls, pullout (sword/sheath) behaviour and angle of stress are studied. It was found that the tensile strength of the tested spinnable CNTs were at least 20 to 90 Gpa with a mean value of 48 Gpa considering a solid cross sectional area.

This paper presents an experimental study on the mechanical performance of sugarcane bagasse fiber reinforced epoxy composite. Tensile and flexural properties of the composites were investigated in this research. Different weightage of short fiber and fiber particulates were utilized to study their effects on the mechanical performance of the composites in terms of tensile and flexural properties. 1% of nano-silica was reinforced to investigate its effect on the mechanical performance of the composites. Hand lay-up composite molding process was used to fabricate the composite samples. During fabrication, ultrasonic mixing was carried out to study the effects on mechanical performance of the fiber particulate reinforced composites. In overall, ultrasonic mixing and addition of nano-silica particles has improved the mechanical performance of the fiber particulate composites. Morphology analysis on surface of composites has shown the removal of air bubbles and deagglomeration. 1wt% of short fiber reinforced composite exhibits the highest tensile and flexural properties among all the samples. Sugarcane bagasse particulates reinforced composites were shown to have better performance compared to short fiber reinforced composites when the wt% of the fiber increase.

Wire rope isolator is one of the most effective isolation system that can be used to attenuate the vibration disturbances and shocks during the operation of machineries. This paper presents the results of investigation on static elastic stiffnesses (both in tension and in compression) of Polycal Wire Rope Isolator (PWRI) under quasi-static monotonic loading conditions. It also studied effect of variations in height and width of PWRI on its static stiffnesses. Suitable experimental setup was designed and manufactured to meet the test conditions. The results show that their elastic stiffnesses for both tension and compression loading conditions are highly influenced by their geometric dimensions. It is found that their compressive stiffness reduced by 55% for an increment of 20% in their height to width ratio. Therefore, the stiffness of PWRI can be fine-tuned by controlling their dimensions according to the requirements of the application.

In this study, the effect of MQL application on the tool wear, surface roughness and chip formation in turning Aluminum alloy 6061 is investigated. Experiments were carried out by plain turning of an Aluminum bar with varying depth of cut, cutting speeds (spindle speed) and cutting environments (Dry, Wet and MQL). A newly designed, cost efficient and portable MQL setup was developed for this study. For each experimental trial, five passes were carried out in order to promote the formation of tool wear. After each pass, the tool surface was examined under a microscope and the surface roughness was measured using a stylus based surface tester. The extent of tool wear from each pass is measured by using ImageJ software. Chips were collected after the five passes and were physically examined. The newly designed MQL delivery system was successful in delivering a fine mist of lubricant at the cutting point. MQL lubrication provided lower surface roughness and tool wear values compared to wet and dry conditions due to effective temperature reduction and improved lubrication penetration of cutting zones, as well as better chip flushing. Chip formed under MQL conditions had reduced chip thickness due to reduced temperatures. MQL was found to have the greatest positive impact on tool wear and surface roughness parameters based on ANOVA results.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief.The article contains significant overlap with a paper that had already appeared in Physica E., 60 (2014) 160-165. http://dx.doi.org/10.1016/j.physe.2014.02.007. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Simple spot weld connection models are desirable in huge and complicated finite element models of automotive body-in-white structures which generally contains thousands of spot weld joints. Hence, in this paper six different individual spot weld joint finite element models simplified in terms of their geometric and constitutive representations were developed including the one that is currently used in automotive industries. The stiffness characteristics of these developed models were compared with the experimental results obtained following a simple strategy to design the welded joint based on the desired mode of nugget pull out failure. It was found that the current spot weld modeling practice in automotive industry under predict the maximum joint strength nearly by 50% for different loading conditions. The computational costs incurred by the developed models in different loading conditions were also compared. Hence, a suitable model for spot welded joints is established which is very simple to develop but relatively cheap in terms of computational costs.