Manufacturing Considerations Research Articles

Consideration of manufacturing induced adhesive damage in automotive simulations

This work contributes to the understanding of damage of adhesive layers generated during the manufacturing process and its effect on the subsequent load carrying capacity of the joint. A temperature dependent cohesive zone model is used to predict damage during the manufacturing process. Therefore, parameters for a temperature-dependent as well as a strain rate-dependent model were determined on various specimens. It is shown, that it is possible to predict the manufacturing induced damage within the adhesive layer with sufficient accuracy using a cohesive zone model. Furthermore, a continuous process chain for numerical simulations is developed, which allows to determine the adhesive layer damage by means of a process simulation and to consider the changed mechanical properties in a subsequent crash simulation. To simplify the procedure, a software tool is presented that automatically performs the described steps. The developed method is applied to a car body simulation to investigate the effects caused by the manufacturing process.

Manufacturability considerations in design optimisation of wave energy converters

Wave energy converter hull shapes have been optimised in the past to find the most suitable design to maximise mean annual power production and minimise costs. However, costs are generally considered through proxies based on the device's size. When using an optimisation process capable of generating very diverse shapes, more complex objective functions may be required to ensure that resulting shapes truly minimise the levelised cost of energy. For this purpose, relevant cost factors with an effect on geometry, such as manufacturability and materials considerations, should be included in the optimisation process. To address this challenge, different strategies for incorporating manufacturability considerations in a wave energy converter optimisation process with an adaptable geometry definition are discussed here. The resulting optimal shapes are compared to the shapes obtained when these additional constraints are not included. The results show that it is possible to generate wave energy converter shapes designed for a particular manufacturing process, as well as in general with improved manufacturability characteristics - based on the shapes maximum curvature. The proposed approaches can be used in future wave energy converter design studies to generate novel and improved shapes while considering their manufacturability.

Integrated design and dimensional compliance of Bound Powder Extrusion technology: A case study of an aircraft engine bracket

Advanced design is guided by requirements and relationships between manufacturing, material, and functions. This research aims to evaluate the dimensional integrity and the design rules for developing an aircraft bracket by atomic diffusion additive manufacturing (ADAM). The key manufacturing considerations are introduced in the design guide to achieve an integrated design approach. This project aims to compare the initial shape of an integrated aircraft engine bracket design and its shape after manufacturing. Mapping of surface deviations was set up to compare the two 3D models, the first one is from CAD and the second model was obtained via 3D scanning.

Global Automakers. CSR Reporting and Targeted Stakeholders 2018-2020

This paper deployed a network-based computational content analysis approach to uncover the major themes and targeted stakeholder groups presented in the top leadership’s corporate social responsibility (CSR) reports’ introductory letters for eleven major global vehicle manufacturers for the period 2018-2020. Themes were based on the 3Ps of sustainability (people, planet, and profit), basic busi­ness practices (economic, legal, ethical, and philanthropic) in the context of CSR, time orientation of the themes whether short- or long- term, and identified target­ed stakeholder groups. This study is unique in that the extant literature reveals no research examining CSR disclosure in the automobile industry from both a sus­tainable goal-directed and practices perspective incorporating potential influenc­es of the COVID-19 pandemic. Results revealed that some vehicle manufacturers focused on investor and economic activities while others communicated a general social responsibility message. During 2020, greater emphasis was placed on in­vestors and somewhat less on society in general. Findings suggest the need for a more balanced representation geared toward addressing pandemic and post-pan­demic challenges as well as traditional automotive manufacturing considerations.

The design of an upper arm prosthesis utilising 3D printing conceived for the 2020 Tokyo paralympic games: A technical note.

This article describes the design and development of an upper-limb prosthesis for a current elite level paracyclist that was conceived for use in the 2020 Paralympic Games. The prosthetic limb was intended specifically for use in cycling time trial events. These are held on the road and in the velodrome whereby the athlete rides using a tucked aerodynamic position. The prosthesis was developed using computer aided design software and an extensive use of the 3D printed manufacturing process. The resulting technical note illustrates the design methodology and manufacturing considerations for a high performance form of assistive technology. However, it results in a solution that challenges the traditional aesthetic of prosthetic limbs intended for sport and physical activity.

Improved composite open-hole compression strength and trade-off with manufacturability controlled by stacking sequence effect and non-standard ply angles

The design of composite laminates requires consideration of part strength and manufacturability, both of which are controlled by ply angle and stacking sequence. This paper studies the open-hole compression strength and forming compatibility of laminates designed with standard angle (SA) and non-standard ply angle (NSA) layups using four different stacking sequence patterns. When increasing interply ply angle differences to provide greater interply lock-up, experimental test results show that dispersed stacking sequences improve failure strength of NSA laminates by up to 36%. Dispersed stacking patterns allow NSA laminates to consistently outperform reference SA laminates with increased failure strengths of up to 17%, indicating that this alternative design may produce stronger structural components. Results for stacking sequences of NSA laminates also reflect an inverse relationship between failure strength and formability . This implies an underlying trade-off between structural strength and manufacturing compatibility, which is worth considering when designing laminates for complex geometries. • Dispersed layups improve open-hole compression strength of non-standard angle laminates by up to 36%. • Non-standard angle laminates with dispersed layups can outperform standard angle laminates on open-hole compression strength by up to 17%. • Results show a trade-off between structural strength and manufacturing compatibility controlled by stacking sequence.

A Multiaxis Tool Path Generation Approach for Thin Wall Structures Made with WAAM

Wire Arc Additive Manufacturing (WAAM) has emerged over the last decade and is dedicated to the realization of high-dimensional parts in various metallic materials. The usual process implementation consists in associating a high-performance welding generator as heat source, a NC controlled 6 or 8 degrees (for example) of freedom robotic arm as motion system and welding wire as feedstock. WAAM toolpath generation methods, although process specific, can be based on similar approaches developed for other processes, such as machining, to integrate the process data into a consistent technical data environment. This paper proposes a generic multiaxis tool path generation approach for thin wall structures made with WAAM. At first, the current technological and scientific challenges associated to CAD/CAM/CNC data chains for WAAM applications are introduced. The focus is on process planning aspects such as non-planar non-parallel slicing approaches and part orientation into the working space, and these are integrated in the proposed method. The interest of variable torch orientation control for complex shapes is proposed, and then, a new intersection crossing tool path method based on Design For Additive Manufacturing considerations is detailed. Eventually, two industrial use cases are introduced to highlight the interest of this approach for realizing large components.

Towards Biomanufacturing of Cell-Derived Matrices.

Cell-derived matrices (CDM) are the decellularised extracellular matrices (ECM) of tissues obtained by the laboratory culture process. CDM is developed to mimic, to a certain extent, the properties of the needed natural tissue and thus to obviate the use of animals. The composition of CDM can be tailored for intended applications by carefully optimising the cell sources, culturing conditions and decellularising methods. This unique advantage has inspired the increasing use of CDM for biomedical research, ranging from stem cell niches to disease modelling and regenerative medicine. However, while much effort is spent on extracting different types of CDM and exploring their utilisation, little is spent on the scale-up aspect of CDM production. The ability to scale up CDM production is essential, as the materials are due for clinical trials and regulatory approval, and in fact, this ability to scale up should be an important factor from the early stages. In this review, we first introduce the current CDM production and characterisation methods. We then describe the existing scale-up technologies for cell culture and highlight the key considerations in scaling-up CDM manufacturing. Finally, we discuss the considerations and challenges faced while converting a laboratory protocol into a full industrial process. Scaling-up CDM manufacturing is a challenging task since it may be hindered by technologies that are not yet available. The early identification of these gaps will not only quicken CDM based product development but also help drive the advancement in scale-up cell culture and ECM extraction.

Design and development of a novel additively manufactured geothermal heat exchanger

The existing geothermal heat exchangers pose a complex installation process and occupy large spaces which can potentially be cost-prohibitive to many potential users. In the present study, an additively manufactured heat exchanger was designed and developed to address this issue. The designed heat exchanger can be integrated with conventional geothermal heating and cooling systems for improved efficiency and easy installation. The additively manufactured heat exchanger developed in the present study eliminates the current need to excavate the soil and install the long piping as conventionally required for the existing geothermal systems. The prototype of the proposed geothermal heat exchanger was designed using CREO software and fabricated using the direct metal laser sintering technique (DMLS) to be integrated into a heat pump to exchange heat between a constant temperature of a water bath circulator and a water heat sink. Furthermore, the support structure model generated for metal printing of the proposed geothermal heat exchanger was exposed and discussed. Two customized geothermal heating and cooling modes were separately developed to evaluate the heat transfer performance of the heat exchanger analytically and numerically. Using the analytical approach, the system sizing was designated based on the metal additive manufacturing and thermal considerations, and then average heat transfer coefficients and pressure drops were estimated for a range of mass fluxes lying in the transitional and turbulent regimes. The distributions of wall temperature, fluid's bulk temperature, and fluid's velocity along the helically-coiled channel of the heat exchanger was also investigated numerically using the COMSOL-Multiphysics. Lastly, a detailed cost analysis was conducted to estimate the total cost per part for the prototype fabricated using the DMLS technology. Novelty Statement A novel ground-source heat exchanger was additively fabricated using the direct metal laser sintering (DMLS) technique. The unique compact screw-type design eliminates the need of excavating soil and features easy installation with less maintenance costs. Heat transfer characteristics of the proposed design were evaluated analytically and numerically. The proposed geothermal heat exchanger contributes effectively to the deployment of sustainable energy systems.

Topology optimization of imperfect frame structures with improved manufacturability

We present a framework for robust topology optimization of frame structures under uncertainty in member geometry. Imperfect geometry is defined as a general out-of-straightness. The uncertainty in response is quantified using a second-order stochastic perturbation that allows for accurate estimation of first and second-order response statistics in the presence of geometric random imperfections. The adjoint method is employed to compute the sensitivities, allowing for the use of gradient-based optimizers. A novel approach based on the augmentation of the set of physical design variables with an “indicator set” and a SIMP-like strategy is utilized to control the complexity of the final design and arrive at optimized topologies with improved manufacturability. Numerical examples are provided to demonstrate the performance of the proposed framework where comparison is made with the deterministic designs to highlight the improvements and differences both in terms of overall topology, e.g., load path diversification, and volume re-distribution and the impact of the manufacturability considerations on the topology of the final design.

Controlled Human Infection Studies: Proposals for guidance on how to design, develop and produce a challenge strain

There is an increasing need to establish quality principles for designing, developing and manufacturing challenge agents as currently these agents are classified differently by various jurisdictions. Indeed, considerations for challenge agent manufacturing vary between countries due to differences in regulatory oversight, the categorization of the challenge agent and incorporation into medicinal/vaccine development processes.To this end, a whitepaper on the guidance has been produced and disseminated for consultation to researchers, regulatory experts and regulatory or advisory bodies. This document is intended to discuss fundamental principles of selection, characterization, manufacture, quality control and storage of challenge agents for international reference.In the development phase, CMC documentation is needed for a candidate challenge agent, while standard operating procedure documentation is needed to monitor and control the manufacturing process, followed by use of qualified methods to test critical steps in the manufacturing process, or the final product itself. These activities are complementary: GMP rules, which intervene only at the time of the routine manufacturing of batches, do not contribute to the proper development and qualification of the candidate product. Some considerations regarding suitability of premises for challenge manufacturing was discussed in the presentation dedicated to “routine manufacturing”.

Manufacturing Bacteriophages (Part 2 of 2): Formulation, Analytics and Quality Control Considerations.

Within this second piece of the two-part series of phage manufacturing considerations, we are examining the creation of a drug product from a drug substance in the form of formulation, through to fill-finish. Formulation of a drug product, in the case of bacteriophage products, is often considered only after many choices have been made in the development and manufacture of a drug substance, increasing the final product development timeline and difficulty of achieving necessary performance parameters. As with the preceding review in this sequence, we aim to provide the reader with a framework to be able to consider pharmaceutical development choices for the formulation of a bacteriophage-based drug product. The intent is to sensitize and highlight the tradeoffs that are necessary in the development of a finished drug product, and to be able to take the entire spectrum of tradeoffs into account, starting with early-stage R&D efforts. Furthermore, we are arming the reader with an overview of historical and current analytical methods with a special emphasis on most relevant and most widely available methods. Bacteriophages pose some challenges that are related to but also separate from eukaryotic viruses. Last, but not least, we close this two-part series by briefly discussing quality control (QC) aspects of a bacteriophage-based product, taking into consideration the opportunities and challenges that engineered bacteriophages uniquely present and offer.

Design and System Considerations for Construction-Scale Concrete Additive Manufacturing in Remote Environments via Robotic Arm Deposition.

This work explores additive manufacturing (AM) of concrete by using a six-axis robotic arm and its use in large-scale, autonomous concrete construction. Concrete AM uses an extrusion method to deposit concrete beads in layers to create a three-dimensional (3D) shape. This method has been found to have many uses and advantages in construction applications. The lack of formwork and autonomous nature of this manufacturing method allows for new geometries and materials to be printed in unsafe or challenging environments. Autonomous construction has been suggested as a method of creating habitats in rapid-response scenarios. This article discusses research toward one such system that could be used to rapidly construct necessary habitats in response to low-resource and emergency situations. This required addressing certain limitations of a six-axis robotic arm platform along with overcoming system challenges to achieve deliverables for NASA's "3D Printed Habitat Challenge." This included system design to increase the build volume, integrate embedding, print non-coplanar sections, and minimize travel moves to address the challenges associated with continuous extrusion of cementitious material. The system was demonstrated by printing a one-third scale habitat, which represents the first 3d-printed fully enclosed structure at an architectural scale without the use of support.

Consideration of additive manufacturing supports for post-processing by end milling: a hybrid analytical–numerical model and experimental validation

Consideration of additive manufacturing supports for post-processing by end milling: a hybrid analytical–numerical model and experimental validation

Topology optimization of 3D photonic crystals with complete bandgaps.

The design of photonic crystals with complete bandgaps has recently received considerable research focus for numerous reasons. This work leverages well-known nonlinear programming techniques to alleviate the non-smoothness caused by degenerate eigenvalues such that topology optimization problems can be solved with the open-source IPOPT software. A fully-vectorial plane wave expansion technique is used with an iterative eigensolver to efficiently predict dispersion properties of candidate structures. Nonlinear programming is employed to solve the inverse problem of designing three-dimensional periodic structures that exhibit complete two-dimensional (2D) and three-dimensional (3D) photonic bandgaps. Mesh refinement is performed to alleviate the large computational burden of designing and analyzing photonic crystals, and a periodic density filter is implemented to impose a minimum feature size for manufacturability considerations.

West Indies technologies in the East Indies: Imperial preference and sugar business in Bihar, 1800–1850s

Today India is among the major sugar producers and sugar-making has a long tradition, yet the adoption of modern sugar technologies was delayed. Which factors underpinned this? This article examines the attempts of European sugar entrepreneurs to adopt new sugar technologies in 1830s–1840s Bihar. Its findings correspond with recent literature on Indian economic development which emphasises the role of declining agricultural productivity in economic stagnation in the colonial period. This article supports the conclusions that low agricultural productivity was the outcome of inadequate investment on the part of the British Empire. It also highlights that in the case of commercial crops – such as sugar – investment into new technologies with potential for increasing productivity was hindered by British trade policies. As British imperial policies gave preference to the welfare of the British consumer, lacked consideration for colonial manufacturing, they did not create a beneficial environment for long-run investment projects.

Continuous twin screw granulation: Impact of microcrystalline cellulose batch-to-batch variability during granulation and drying – A QbD approach

Despite significant advances in the research domain of continuous twin screw granulation, limited information is currently available on the impact of raw material properties, especially considering batch-to-batch variability. The importance of raw material variability and subsequent mitigation of the impact of this variability on the manufacturing process and drug product was recently stressed in the Draft Guidance for Industry on Quality Considerations for Continuous Manufacturing by the U.S. Food and Drug Administration (FDA). Therefore, this study assessed the impact of microcrystalline cellulose (MCC) batch-to-batch variability and process settings in a continuous twin screw wet granulation and semi-continuous drying line. Based on extensive raw material characterization and subsequent principal component analysis, raw material variability was quantitatively introduced in the design of experiments approach by means of t1 and t2 scores. L/S ratio had a larger effect on critical granule attributes and processability than screw speed and drying time. A large impact of the t1 and t2 scores was found, indicating the importance of raw material attributes. For the studied formulation, it was concluded that MCC batches with a low water binding capacity, low moisture content and high bulk density generated granules with the most desirable quality attributes. Additionally, an innovative and quantitative approach towards mitigating batch-to-batch variability of raw materials was proposed, which is also applicable for additional excipients and APIs.

Deployable Convex Generalized Cylindrical Surfaces Using Torsional Joints

Abstract The ability to deploy a planar surface to a desired convex profile with a simple actuation can enhance foldable or morphing airfoils, deployable antennae and reflectors, and other applications where a specific profile geometry is desired from a planar sheet. A model using a system of rigid links joined by torsional springs of tailorable stiffness is employed to create an approximate curved surface when two opposing tip loads are applied. A system of equations describing the shape of the surface during deployment is developed. The physical implementation of the model uses compliant torsion bars as the torsion springs. A multidimensional optimization algorithm is presented to place joints to minimize the error from the rigid-link approximation and account for additional manufacturing and stress considerations in the torsion bars. A proof is presented to show that equal torsion spring spacing along the horizontal axis of deployed parabolic profiles will result in minimizing the area between the model’s rigid-link approximation and smooth curve. The model is demonstrated through the physical construction of a deployable airfoil surface and a metallic deployable parabolic reflector.

Design and Analysis of a Water-Cooling System in a New Yokeless and Segmented Armature Axial In-Wheel Motor for Electric Vehicles

Abstract An in-wheel motor, as a key part of an in-wheel driving system, needs to satisfy strict restrictions on thermal balance for increasingly high-power density in limited space and weight. Therefore, a new in-wheel motor with an innovative water-cooling system for one newly developed electric vehicle was developed. Based on the mechanical structure of the motor, all potential water-cooling layouts were first designed with consideration of mechanical strength and manufacturability. A thermal conjugate simulation model of the developed in-wheel motor was then built, and its thermally fluid–solid interactions were investigated in this study. All potential water-path layouts of the motor were compared regarding the cooling effect and fluid resistance, which impact the performance of the motor. Fluid flow velocity and fluid state, determined by the water-path layout, significantly impact the cooling effect of the motor. The well-designed water-cooling system significantly reduces the motor’s temperature at a low cost on required coolant-driven pressure which benefits the efficiency of the developed motor. A prototype of the developed motor with the optimal water-path layout was built and tested on the test rig. The developed motor provides outstanding thermal performance.

Research on Corrosion Management Technology of Petroleum Pipeline and Pressure Vessel

At present, the corrosion management of the upper module pressure vessel and pressure pipeline of the fixed oil production platform and the floating production oil storage and unloading platform lacks localized corrosion rate knowledge base, corrosion mechanism knowledge base and inspection case knowledge base, resulting in low accuracy of evaluation results and the foundation of integrity management is weak. Based on this background, the paper discusses the leading causes of the corrosion process and studies and analyses the primary mechanism. Through careful consideration of pressure vessel design, material selection, manufacturing, coating and slow release and other factors, combined with different corrosion mechanisms, a comprehensive analysis of the corrosion protection of pressure vessels is carried out to find the best method of corrosion protection and corrosion control to ensure Pressure vessels operate safely and typically in petrochemical production.