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In this paper, fatigue life of coil springs was\ud investigated as failure due to high cyclic loading during\ud their service life is more common. For this purpose,\ud two exclusive rear coil compression spring geometries\ud were investigated using material type - siliconchromium\ud steel SAE-AISI 9254 for this application. For\ud these design models, the effect of changing component\ud geometry using varying pitch arrangements of coils were\ud examined to understand their structural durability and\ud ability to withstand cyclic loading conditions. A finite\ud element model based on industry standard designs\ud was created to simulate real-life spring performance.\ud In this study, the varied pitch designs were subjected\ud to lower stresses in static analysis and have longer life\ud estimates in the fatigue analysis. This confirms that\ud a varied pitch can improve the performance of a coil\ud spring. The result shows that design-1 incorporated a\ud pitch design that reduced pitch at the centre coils of the\ud spring performed better.

Materials recycling and additive manufacturing (AM) present challenges and great opportunities in plastic industries. The rapid developments in AM are transforming the manufacturing industry. Reducing CO2 emissions, saving cost, and escaping from landfill are the decisive factors in this transformation.\ud \ud In this study, to mitigate any risk caused by production speed and scaling and accelerate shift towards a more localized recycling and manufacturing of plastic parts and components, a collection-recycling-manufacturing (CRM) model is built to envision the evaluation of process flow as well as process integration.\ud \ud The novelty of the CRM model enables optimization between recycling facilities and transportation distance calculation. It further strengthens a seamless integration between recycling and AM processes and envisions the areas that need enhancements. The study reveals that AM creates opportunities such as prototyping, customizing, transportation cost reduction, and creation of jobs in rural areas, which may stop unnecessary immigration; and, most importantly, reducing CO2 emissions and plastic waste despite challenges such as skills requirement and disadvantages in speed and scale production.\ud \ud With a combination of recycling and AM, sustainable manufacturing can be achieved effectively, although several conditions must be met and obstacles must be overcome. A few innovations are further proposed in this study to streamline the transformation and to support the “cradle-to-cradle’’ approach towards “zero waste” for a sustainable future.

Working together harmoniously in an engineering team is crucial to achieve success and is essential to the team members’ wellbeing. This study examines what types of personalities hinder the harmony across engineering teams and the outcome of this study is crucial to recognise how to maintain harmony across engineering teams with diverse personalities. Consequently, the data is collected from experienced engineering team leaders as well as an experienced psychologist. This study shows that in the engineering industry personalities are looked at from a different perspective and their characteristics are perceived from a business point of-view as opposed to the literature in which judgments are made upon the personality description.

The contour method is one of the promising techniques for the measurement of residual stresses in engineering components. In this method, the cut surfaces deform, owing to the relaxation of residual stresses. The deformations of the two cut surfaces are then measured and used to back calculate the 2-dimensional map of original residual stresses normal to the plane of the cut. Thus, it involves four main steps; specimen cutting, surface contour measurement, data analysis and finite element simulation. These steps should perform in a manner that they do not change the underlying features of surface deformation especially where the residual stress distribution varies over short distances. Therefore, to carefully implement these steps, it is important to select appropriate parameters such as surface deformation measurement spacing, data smoothing parameters (‘knot spacing’ for example cubic spline smoothing) and finite element mesh size. This research covers an investigation of these important parameters. A simple approach for choosing initial parameters is developed based on an idealised cosine displacement function (giving a self-equilibrated one-dimensional residual stress profile). In this research, guidelines are proposed to help the measurer to select the most suitable choice of these parameters based on the estimated wavelength of the residual stress field.

An EB welded P91 steel plate is selected to measure longitudinal residual stresses (acting in the welding direction) using the contour method. The EB weld causes short length scale residual stresses within the narrow width of the fusion zone with steep stress gradients lateral to the weld line. In order to capture the short length scale residual stresses and improve the spatial resolution of the contour method, the special measures were taken for all main four steps of the technique. For this improved approach, first the specimen cutting was performed with the special care. A thin cutting wire diameter (10 µm rather than standard 25 µm) was used to achieve a better surface roughness, the surface deformation was sampled at a higher frequency, and then, the data analysis steps were performed precisely to measure the short length scale residual stresses, the data smoothed over an optimum length-scale and an appropriate finite element mesh density was chosen. The success of the measurement is assessed by comparing the new contour method result to the published first conventional contour measurement result and the neutron diffraction result for the same component. Previously, the initial conventional contour method measurement was unable to resolve the tensile stress peaks in the HAZs adjacent to the weld fusion zone. However, the new contour measurement residual stresses are in good agreement to the neutron diffraction results. It is also shown that the new contour measurement results has been successfully captured the steep stress gradient on both sides of the weld centre-line (0 mm) with tensile stress peaks situated just 2.6 mm apart.

The braking system is an important and indispensable part of an automotive. The brake disc rotor forms part of the braking system and plays a significant role to effectively stop the vehicle. Therefore, the investigation of rotor design and analysis is important towards attaining optimal braking performance. In this research, three designs of vented rotor geometry were tested, namely normal vented, vented and cross-drilled and vented and slotted, and subjected to coupled thermal-structural analyses using ANSYS Workbench. For material selection for these designs, the CES EduPack software was applied and Carbon/Carbon (C/C) composite was identified as the best material for use as a rotor material for racing application. The results showed that the vented and cross-drilled design is the most appropriate design for the vehicle applications since it records lowest maximum temperature, stress, strain and total deformation compared to the other two design. This design also helps to enhance brake performance by allowing for faster heat dissipation and hence reducing thermal stresses on the rotor.

In pressure vessels stainless steel weld-overlay cladding is a widely used technique to provide a protective barrier between the corrosive environment and the ferritic low alloy base metal. While the cladding layers enhance corrosion resistance, the induced residual stresses due to the deposition of weld layers are of major concern. It is of paramount importance to understand how residual stresses interact with service loading when the vessel is pressurized. Therefore, knowledge of the initial residual stresses due to cladding is an essential input for structural integrity assessment of pressure vessels.\ud \ud In the present paper the Contour Method was conducted to measure residual stresses in an austenitic steel cladded plate that was fabricated from a ferritic steel base plate with three layers of austenitic stainless steel weld metal cladding deposited on the top surface. The Contour Method was chosen for various reasons. First, it provides a full 2D variation of residual stresses over the plane of interest. Second, it is not limited by the thickness of components or microstructural variations and finally it should potentially capture the variation of residual stresses in each individual weld beads and due to the possible phase transformation in the ferritic base material. The map of longitudinal residual stresses was measured by sectioning the test component along a transverse plane at mid-length. The measured residual stresses were in good agreement with published results in the open literature

An anisotropic damage model capable of predicting the response of normal and high strength concretes is presented in this study. The model utilizes a concrete appropriate effective compliance matrix in constructing the constitutive equations. Three parameters alpha, beta\ud and gamma were used in the effective compliance matrix. Alpha and beta are introduced to model the different behaviour of concrete in tension and compression while the third parameter gamma was introduced to account for volumetric change. The concept of multiple surfaces i.e. limit fracture surface, loading function surface and bounding surface, defined in strain-energy release space, is used to define the evolution of damage. After calibration for various strengths of concrete, ranging from 27.6 MPa to 120 MPa, the predictive capability of the proposed elasto-damage model for uniaxial and biaxial stress paths was investigated for uniaxial compression, biaxial compression, uniaxial tension and tension-compression. The simulative capability of the model to capture the phenomenological behaviour of concrete such as strain softening, stiffness degradation, biaxial strength envelope, volumetric dilatation, different behaviour in tension and compression, and gain in strength under increasing confinement is reflected. The predicted results correlate well with the available experimental data.

3D printing or Additive Manufacturing (AM) is an emerging technology with great potential for the future. As an alternative to Conventional Manufacturing (CM) processes, the unique features of AM, such as enormous freedom of design, quick prototyping, easy entry, and higher materials yield, are paving the way toward sustainability. Nevertheless, AM can be challenging due to the weakness in manufacturing scaling and standards, and lower production speed. \ud In sustainability, environment, societies and economies are the pillars, and AM assists sustainable manufacturing in reducing cost and lead time. Compared to CM, AM significantly enhances flexibility and shaping via the layer-by-layer method rather than subtracting processes. \ud In this paper, the integration of plastic recycling and Home Based Manufacturing by 3D printing, through standardization and collaboration for a more sustainable future is discussed. This study indicates that strategy control of local recycling and 3D printing of plastics reduces energy consumption and CO2 emissions throughout the supply chain. More importantly, AM manufacturing may create jobs locally and reduces physical migration

Deterioration of civil engineering infrastructure may be attributed to the aging, environmentally induced degradation, poor initial design and/or construction, lack of mainte-nance, change of use, more stringent design criteria and natural events such as earthquakes. Non-corrosive fiber reinforced polymer (FRP) reinforcement have recently made major break-throughs in civil engineering applications. FRP rehabilitation is a cost-effective, state-of-the-art technology in the repair and strengthening of structures. Use of Carbon Fiber Reinforced Poly-mer (CFRP) Plates, as externally bonded reinforcement, is a practically efficient and technically sound method of strengthening and upgrading structurally inadequate or otherwise damaged or deteriorating reinforced concrete (RC) members. Externally bonded plates help in improving the structure performance by reducing deflections or cracking and increasing ultimate strength. The ultimate capacity of the strengthened beam is controlled by either compression crushing of con-crete, rupture of the composite plate, local failure of concrete at the plate end due to stress con-centrations and flexural shear crack-induced debonding of Concrete-CFRP interface. Another factor that could affect the ultimate strength and mode of failure is the shear span. These failure modes along with the variation of shear span were considered in this study to investigate the ul-timate load carrying capacity and failure modes of strengthened beams. Beams with U-shaped anchorages were tested in four point bending to determine the ultimate load carrying capacities of the beams. Properly placed U-shaped anchorages at plate cut-off points and along the span were shown to be effective in optimizing the deformability and strength characteristics of CFRP strengthened RC beams in flexure and shear.

Dissimilar metal weld joints are widely used in safety-critical applications including nuclear power generating plants, chemical and petrochemical industries as well as conventional power systems [1]. When joining dissimilar metals the weld thermal cycle adversely affects the weld region, causing microstructural changes and large variations in physical, mechanical and chemical properties across the joint. These variations arise due to the metallurgical and physical incompatibility of the two metals. High energy density electron beam (EB) welding can reduce dissimilar metal joining problems to some extent and potentially produce satisfactory joints. The low heat input per unit length of EB welds results in a small weld bead size with a high depth to width ratio. This limits the extent of the heat affected zone, reduces distortion and restricts the range of tensile residual stresses. EB welding has been identified as a potential technique for joining stainless steel to modified 9Cr-1Mo ferritic steel for high temperature applications. However, EB welding has some disadvantages. The relatively small volume of molten material formed in the welding process rapidly solidifies and shrinks which can cause cracking in the weld metal and highly triaxial residual stresses with a steep gradient moving away from the weld line [2] that are difficult to measure and predict.\ud The contour method has emerged as a promising technique for the measurement of residual stresses in engineering components. This method was invented in 2000 by Mike Prime [3]. It is based on cutting the test component of interest into two halves by wire electro-discharge machining. The cut surfaces deform behind the cutting wire owing to the progressive relaxation of residual stresses. The deformation contours of the two cut surfaces are then measured, and used to back calculate a 2-dimensional map of original residual stresses acting normal to the plane of the cut. Nevertheless, like other residual stress measuring techniques, the contour method also suffers from factors that introduce uncertainties in the measured stresses impact and limit its spatial resolution.\ud In this paper, longitudinal residual stresses (acting in the welding direction) in an EB dissimilar metal weld joining AISI Type 316LN stainless steel to P91 modified 9Cr-1Mo steel were measured using the contour method. The narrow width of the EB fusion zone introduced short length scale residual stresses with steep stress gradients lateral to the weld line which presented a new challenge for the contour method. This challenge was addressed by taking special measures with respect to cutting and data analysis. A smaller cutting wire diameter (50 μm rather than standard 250 μm) was used to achieve a better surface roughness, the surface deformation was sampled at a higher frequency, the data smoothed over an optimum length-scale and an appropriate finite element mesh density chosen.\ud A cross-section map of the longitudinal residual stress measured by the contour approach described above is presented in Fig. 1. A line profile of contour results at 5.5 mm below the top surface of the plate is shown in Fig. 2. This result is compared with published data for the same component obtained by neutron diffraction and incremental centre-hole drilling residual stress measurement techniques [4]. Steep stress gradients on both sides of the weld centre-line (0 mm) have been resolved by the contour method with maximum tensile stress peaks situated just 2.3 mm apart. To the author’s knowledge this is a shorter residual stress length scale than previously measured by the contour method.

Over the years, the cumulative environmental impact from human activity has disrupted the stability of the natural world, warming the planet above pre-industrial levels. Whilst unprecedented in many ways, reducing industrial emissions from greenhouse gases could help stabilise rising temperatures. Thus, the exploration for more sustainable manufacturing solutions that reduce carbon emissions is imperative. Some traditional manufacturing (TM) processes, such as sand casting, which, despite its versatility to produce products in many shapes and sizes from almost any metal or alloy, are typically energy-intensive activities. Conversely, metal additive manufacturing (MAM) enables users to manufacture more complex, lighter and near net shapes with the ability to consolidate manufacturing workflows. Consequently, MAM has been reported to be an energy-efficient alternative. Yet, evidence in the literature on the environmental impact of some MAM processes is limited, especially for material extrusion (ME) additive manufacturing (AM) methods such as the atomic diffusion additive manufacturing (ADAM) process. This paper explores the feasibility of performing a life cycle assessment (LCA) for the ADAM process compared to sand casting. Preliminary results indicate that the ADAM process demands 71.04 kWh/kg and 16.57 CO2 equivalent (CO2-eq) more for manufacturing 1kg of 17-4 precipitation hardened stainless steel (17-4 PH SS) compared to sand casting. Therefore, the findings collected from this pilot study justify future research efforts to converge on developing a novel model for performing a comprehensive cradle to grave LCA for ADAM to compare against sand casting and other TM processes such as CNC milling and investment casting.

The fastest growing thread of climate change has roused the world to take some pragmatic actions to protect natural world heritage. United Nations take a significant step to address this serious issue and establish the 2030 Agenda for Sustainable Development for people, planet and prosperity, and set 17 goals which all countries have to act upon for sustainable development. One of the goals is sustainable consumption and production. In the current situation, it is crucial to take it into account in all fields of engineering for existing and new developments. All engineering products need to be designed in a way that they can be recycled and lead to zero waste to minimise their environmental impact and truly assist the cradle-to-cradle approach. In this paper, the potential use of sustainable materials for industries that can be processed and recycled to convert into the value-added products are discussed. This discussion is facilitated by overviewing the published papers related to sustainable material selections for different engineering applications.

Fused deposition modelling (FDM) is a popular but complex additive manufacturing process that works with many process parameters which are crucial to investigate. In this study, 3D parts were fabricated by placing each filament layer in opposite direction to the others, for this, two combinations of raster angles, (45° −45°) and (0° 90°), along with three different infill speeds were used. In this study, two 3D printing material types—Polylactic Acid (PLA) and tough-PLA were used. The material properties of each 3D part were investigated to identify the best combination of these parameters. A microstructural analysis was also performed on outer and inner surfaces along with fracture interface of the parts after tensile testing using a scanning-electron-microscopy (SEM) to explain material failure modes and reasons. The results suggest that for both the material types, a raster angle of 45° −45° produces stronger parts than to a raster angle of 0° 90°. This study also suggests that a slow infill speed improves tensile properties by providing a better inner-connection between two contiguous roasters. Thus, the detailed analysis of microstructural defects correlated with tensile test results provides insight into the optimisation of raster angle and infill speed, and scope for improvement of mechanical properties.

In this research, an electron beam (EB) butt-welded P91 steel plate (~9 mm thick) is selected to measure longitudinal residual stresses (acting in the welding direction) using a promising residual stress measurement technique - the contour method. The EB weld causes short length scale residual stresses within the narrow width of the fusion zone with steep stress gradients lateral to the weld line, which presents a new challenge for the residual stress measurements. The special measures were taken for all main steps of the technique to improve its the spatial resolution, thereby the short length scale residual stresses were captured. The success of the measurement is assessed by comparing the contour method result to the neutron diffraction result, and a good agreement were found in the results of both the techniques. These results also shows that the contour measurement results successfully captured the steep stress gradient on both sides of the weld centre-line (0 mm) with tensile stress peaks situated just 2.8 mm apart. It is one of the best resolutions in residual stress length-scale in this component achieved in contour measurements., The contour method; High energy density welding (HEDW); Electron beam welding (EB); P91 steel; Wire electrical discharge machine (WEDM).