Physical models of bony areas are used in the medical environment for training, patient information or for various examinations. These are idealized average models which, however, do not reflect the ...individuality of a respective patient. Furthermore, the mechanical properties of the bony structure with cortical bone and cancellous bone are not considered in most models. A few manufacturers, such as SawBone, offer models and material blocks that approximate the properties of the bone. However, these are not patientspecific either. This paper presents a proposal for a method to create patient-specific physical bone models with CAD/CAM technologies that approximate shape and mechanical properties. The models are made of two different rigid polyurethane foams for cortical bone and cancellous bone. The methodical development includes the elaboration of a framework starting from the patient's CT data, through design derivation, to fabrication. Furthermore, a possible process for fabrication in the form of a demonstrator and its application in sawing tests will be demonstrated.
Abstract Despite technological and medical advances, amputations continue to increase. Amputees face significant challenges when acquiring and using prosthetic devices, challenges which are made ...worse as their emotional needs, aspirations, mobility, prosthesis requirements and problems change over time. These challenges require custom solutions for each individual amputee, a fact that current amputee centered prosthesis services tend to ignore. The work reported in this paper contributes an AI based Prosthesis Development Service Framework to cater for the current and evolving needs of amputees.
In current implantology, calcium phosphate cement (CPC) is increasingly used. A special focus is given to CPC scaffolds, as they are suitable for cell settlement and growth due to their positive ...osteoconductive properties. The design of the scaffolds is of decisive importance for this. The value ranges of the geometric parameters of these scaffolds (e.g. path distance, path diameter), which are positive for both cell settlement and cell growth, are very small. Manufacturing deviations therefore have a significant impact on cell settlement and growth. The pasty manufacturing consistency can cause sagging at the path interstices of a layer immediately below, resulting in significant manufacturing deviations. A larger path distance and thus a larger path interstitial space promotes cell settlement, but at the same time increases the risk of CPC path shape inconsistency. This in turn can have a negative effect on cell settlement. Therefore, the aim of this paper is to investigate the discrepancies between the nominal and actual state at a path distance favourable to cell settlement on the basis of manufactured CPC scaffolds. In this context, geometric and manufacturing parameters of the shape deviation are to be identified and constructive design adaptations are to be derived on the basis of these. In addition, the effects of the shape and position deviations on the flow behaviour will be investigated.
Geometric deviation associated with the assembly of sheet metal is a general concern for manufacturers. The typical assembly step involves a sequence of events that exert forces on the parts to ...enforce them to the nominal condition and to connect the parts together. The simulation and optimization of the assembly steps often neglect the sequence of operations due to the problem and computation complexity. This paper investigates the influence of the clamping sequence in the body-in-white (BIW) manufacturing process on the geometrical quality of the assembly. An approach for modeling clamping sequences for non-rigid variation simulation is introduced in a digital twin context, taking the part deviation into consideration. An optimization method is proposed to achieve minimum geometric deviation after clamping the parts and welding them together. The method is successfully applied on two reference assemblies, and the results show that the sequence of clamping can impact the total geometric deviation up to 31%. Combining clamping and welding sequence optimization can enhance the quality improvement to 77% after releasing the assembly from the fixture and springback.
Abstract Agile methods are increasingly being used in automotive development. This research delves into the current state of agile transformation in the automotive industry regarding benefits, ...challenges, organizational adaptations, and successful measures to establish the agile approach. The results of an online survey reveal that benefits are already evident after 6 months and that challenges are mainly organizational in nature and organizational structures need to be adapted. Main drivers of success are pilot projects on a small scale and top management support as well as training managers.
For sinus grafting, different methods and materials are available. One possible shortcoming of particulate bone grafts is either overfilling or augmenting the planned implant area insufficiently. To ...overcome this risk and to determine the implant position prior augmentation, we present an approach using three-dimensional printed scaffolds. A patient with a remaining anterior dentition and bilateral severely atrophied posterior maxilla was seeking oral rehabilitation. The cone beam computed tomography (CBCT) showed residual bone heights between one and two millimeters. Following the three-dimensional reconstruction of the CBCT data, the positions of the implants were determined in areas 16 and 26. Three-dimensional scaffolds adapted to the topography of the sinus were virtually designed and printed using a calcium phosphate cement paste. Bilateral sinus floor augmentation applying the printed scaffolds with an interconnecting porosity followed. After nine months, a satisfying integration of the scaffolds was obvious. At the re-entry, vital bone with sufficient blood supply was found. One implant could be placed in positions 16 and 26, respectively. After five months, the implants could be uncovered and were provided with a temporary denture. The application of three-dimensionally printed scaffolds from calcium phosphate cement paste seems to be a promising technique to graft the severely atrophied posterior maxilla for the placement of dental implants.
This work aims to evaluate the current state of research on the use of artificial intelligence, deep learning, digitalization, and Data Mining in product development, mainly in the mechanical and ...mechatronic domain. These methods, collectively referred to as “digital engineering”, have the potential to disrupt the way products are developed and improve the efficiency of the product development process. However, their integration into current product development processes is not yet widespread. This work presents a novel consolidated view of the current state of research on digital engineering in product development by a literature review. This includes discussing the methods of digital engineering, introducing a product development process, and presenting results classified by their individual area of application. The work concludes with an evaluation of the literature analysis results and a discussion of future research potentials.
Abstract The application of agile development methods in response to increasing market dynamics and product complexity is a key lever in the automotive industry. Agile methods originally come from ...the software industry and enable fast, flexible and customer-oriented product development. These methods are also increasingly being used in hardware development. However, the evaluation of the benefits of agile methods in the context of automotive development has been primarily subjective. The publication aims to present a first data-based approach to objectify the benefits of agile methods in automotive development by highlighting the effects in the quality of collaboration within teams. A standardised procedure is therefore designed and presented. On the one hand, a model for measuring the agile maturity of teams is described. On the other hand, the quality of collaboration within a team is examined in different aspects using standardised key performance indicators. Based on the proposed procedure, a strong positive correlation was found between the considered key performance indicators of the quality of collaboration and the agile maturity of the development teams within the investigated organisation.
Abstract In reengineering technical components, the robust automation of reverse engineering (RE) could overcome the need for human supervision in the surface reconstruction process. Therefore, an ...enhanced computer-based geometric reasoning to derive tolerable surface deviations for reconstructing optimal surface models would promote a deeper geometric understanding of RE downstream processes. This approach integrates advanced surface information into a deep learning-based recognition framework by explicitly labeling geometric outliers and subsurface boundaries. For this purpose, a synthetic dataset is created that morphs nominal surface models to resemble the macroscopic surface pattern of physical components. For the detection of regular geometry primitives, a 3D-CNN is used to analyze the voxelized components based on signed distance field data. This explicit labeling approach enables surface fitting to derive suitable shape features that fulfill the underlying surface constraints.
Abstract Water scarcity and resource depletion can be expected during the climate crisis. Therefore, thermally loaded processes in particular, must be made more efficient in the future. Heat ...exchangers will play a key role in this optimization process. More efficient designs allow a greater heat flow to be removed from processes while mass flows remain constant. In this context, the heat-transferring wall of heat exchangers is a focus of current research on the design of heat exchangers. The aim is to increase the heat-transferring surface of the wall as much as possible and to keep the design space as compact as possible. Therefore, this study investigates the suitability of the differential-growth method for generating complex heat-transferring walls for heat exchangers using CFD-analysis. Firstly, a framework for generating the wall structures and a computational model for predicting the design influence of such structures for the thermal and fluid-dynamic behavior of the heat exchanger are presented. Thereby, the potential of such wall structures is analyzed in this study. Furthermore, the study identified weaknesses of such walls designed with the differential-growth method, which should be the focus of future investigations.
