CAD Design Research Articles

Formula Student versenyautó csővázának optimalizálása

The aim of this research is to design the pipe frame structure of a Formula Student race car. The design considers the aspects defined in the regulations and is adapted to the chassis geometry. The pipe frame structure is designed in a CAD design program (SolidWorks) considering the dynamic properties of the chassis geometry. The engine to be installed in the race car is a single-cylinder internal combustion engine, the positioning of which in the pipe frame and the definition of the appropriate connection points must be ensured. Based on experience from previous design processes, the optimisation of driving stability and torsional stiffness will be provided as a result of the study.

Design for Additive Manufacturing Education of Process Engineering Students on an Industrial Challenge

As the use of additive manufacturing (AM) is increasing in many sectors, the need of design education for AM has gained importance. Solving the challenges of an application with the advantages of AM requires competencies in selecting a suitable AM process, identifying design opportunities and designing for AM based on an extensive knowledge in the application domain. Hence, it is necessary for all branches engineering to develop AM skills and competencies. This paper describes a lecture and practical to develop AM design competencies in chemical process engineering master students. The course teaches designing complex AM parts based on the need of an application by combining the opportunistic and restrictive aspects AM design with the domain-specific functional requirements. The design education benefits from AM’s advantages in rapid prototyping to provide feedback within the time frame of a course. In order to fulfill the above requirements, an application-oriented design course from requirements to testing, involving a simplified real industrial design problem, has been prepared. Students obtain design requirements at the beginning of the practical and have to develop a device using the advantages of AM. After completing CAD design, the designs of the students are produced with the laser based powder-bed fusion of metal (PBF-LB/M) and bath-based photopolymerisation of polymers, curing using ultraviolet light (VPP-UVL/P) methods. The manufactured designs are tested on the test bench provided by the institute. A case study of a hybrid manufactured reactor with internal condensation supports the conclusion of this paper.

BIM-технології в будівництві: сучасні виклики для України

In accordance with the important needs of our time, it is relevant to study the methods, the use of which is most appropriate for the restoration of damaged construction sites as a result of military aggression. Improving the quality of work control at each stage, reducing the cost and ensuring the safety of construction requires the use of innovative technologies, in particular building information modeling (BIM). The article analyzes in detail the features of BIM technologies, reveals the essence of BIM modeling and BIM model. In the work, the building information model is considered as a three-dimensional model, the task of which is to unite all participants in the construction process at each stage. An analysis of the differences between CAD design technology and BIM is carried out, the factors that determine the complexity of the implementation of BIM design in Ukraine are presented, the main points of the development of an effective BIM conception are structured. In addition, a study of foreign practices on the use of BIM to work with damaged objects requiring reconstruction is carried out. The results of the carried out study indicate the need to introduce BIM technologies as one of the basic steps towards digitalization of the construction industry. BIM technologies in modern realities are gradually becoming a priority of sectoral policy on the part of the State. In particular, the article presents the Conception, which contains the main provisions and mechanisms of the State policy aimed at laying the foundation for digital transformations of the construction industry. The importance of BIM technologies for improving the efficiency of construction is economically substantiated and confirmed by statistical data. The need to introduce BIM technologies as an innovative and more effective tool in the reconstruction and restoration of buildings is emphasized.

A randomized clinical study evaluating the 30-month clinical performance of class II indirect restorations in endodontically treated teeth using ceramic, hybrid, and composite computer-aided design/computer-aided production blocks.

In the literature, the information about which indirect material is the most appropriate for the restoration of endodontically treated teeth is insufficient. Therefore, studies evaluating the clinical performance of root canal-treated teeth will shed light on this issue for clinicians. This clinical study aimed to evaluate the clinical performances of class II indirect restorations using ceramic, hybrid, and composite blocks to endodontically treated teeth. A total of 60 indirect class II restorations were performed in 51 patients using Cerasmart (GC Dental Products Europe, Leuven, Belgium) composite, IPS e.max computer-aided design CAD (Ivoclar Vivadent, Schaan, Liechtenstein) ceramic, and Vita Enamic (Vita Zahnfabrik, Bad Sackingen, Germany) hybrid blocks. All the restored teeth had root canal treatment. The restorations were evaluated using modified FDI criteria for 30 months. The data were analyzed using Kruskal-Wallis analysis and Friedman two-way analysis of variance. A total of 53 restorations of the 60 restorations could be followed up at the end of 30 months. No statistically significant difference was observed between the groups after 30 months in terms of all criteria evaluated (P > 0.05). Composite, ceramic, and hybrid blocks showed successful clinical performance in endodontically treated posterior teeth with large material loss.

STRUCTURAL DESIGN OF A WORKBENCH FOR THE NEEDS OF A SERVICE TECHNICIAN

The presented paper deals with the structural design of a workbench with adjustable height, which will serve as part of the equipment of a light commercial vehicle for the needs of a service technician. The main objective of this paper is to create a functional design and 3D CAD model of a workbench that will meet the requirements of safety, mobility, and simple utilisation. Moreover, the design needs to consider the requirements of adjustable height and the dimensions of the work vehicle. The lifting mechanism is represented by arms fitted with sleeves that move along a lead trapezoidal screw rotating by a hand crank. In this paper, the force action in the axis of the threaded rod of the lifting mechanism is scrutinised in two extreme positions (highest and lowest position). The highest axial load on the threaded rod was found to be 9927.13 N in the lowest position of the mechanism. On the basis of this load, a right and left-hand trapezoidal threaded rod TR16×4 is selected, which satisfied the strength condition. The design of the sleeve height and the number of sleeve threads required are essential for safe utilisation. Due to the dimension of the guide rod, the height of the sleeve is selected to be 40 millimetres. The work surface is an important part of the workbench and consists of two parts. The chief larger part is made of medium density fibreboard and the smaller modular part can be in the two modular forms. The first version is the medium density fibreboard, and second alternative is a board designed to fix the components during their maintenance, repair as well as for welding.

Designing a Synthetic 3D-Printed Knee Cartilage: FEA Model, Micro-Structure and Mechanical Characteristics

Articular cartilage morphology and composition are essential factors in joint biomechanics, and their alteration is a crucial aspect of osteoarthritis (OA), a prevalent disease that causes pain and functional loss. This research focuses on developing patient-specific synthetic cartilage using innovative Digital Anatomy polymers. The objectives include investigating the morphology, characterizing the mechanical properties, and replicating the architecture of natural cartilage. This approach offers potential alternatives to traditional manufacturing methods and reduces the need for expensive in vivo experiments. Finite Element Analysis (FEA) validates a novel patient-specific measurement setup. It provides insights into the role of morphology in the distribution of stress and strain within cartilage. CAD design is also utilized to create standardized fiber-reinforced samples that mimic the layered micro-architecture of natural cartilage, allowing for the study of their contribution to the overall mechanical properties. The results demonstrate that 3D-printed polymers can effectively replicate the elastic properties of cartilage. The proposed patient-specific simulator produces reliable results, which have been validated through FEM analysis. While the recreated microstructure closely resembles biological cartilage samples, the elastic properties are slightly underestimated. In conclusion, designing an in silico knee joint is a feasible approach that offers numerous advantages for further development. The Young’s modulus values of our synthetic cartilage modules range from 2.43 MPa to 7.24 MPa, within the range reported in the literature. Moreover, Young´s modulus at the micro level shows the differences between surface 1.74 MPa and internal substrate 1.83 MPa depending on the fiber orientation. Finally, our model proves to be mechanically and morphologically accurate at both the macro and micro levels.

Vehicle Underhood Environment Investigations Using a Simplified Test Rig

Energy efficiency and thermal management continue to be critical areas in the vehicle development process. Independent of whether it is a vehicle with an internal combustion engine, hybrid, or fully electrical, engineers require proper and accurate tools to comprehend heat transfer in engine bays. However, developing such tools using a fully detailed production geometry can be challenging. This work presents a simplified and flexible test rig design of the vehicle underhood environment in two different variants: a passenger car and a commercial truck. The rig design in CAD and experimental data for the two rig configurations are made available upon request. These data will allow for the validation of different simulation approaches against the experimental dataset. An example of such a validation is presented in this paper. The load case scenario represented includes constant speed driving under heavy loads continued by a complete halt, which is followed by soaking for 100 min. The differences in experimental results for different rig variants are shown and analyzed. A good correlation between the experiments and CFD is obtained.

Desain Sistem Mekanik Robot SCARA untuk Internet Nuclear Instrumentation Laboratory

Radiation protection training requires a robotic arm as a radiation shield regulator that can be controlled remotely to reduce radiation risk. The required robot is a Selective Compliance Assembly Robot Arm (SCARA) type robotic arm. This research aims to design a mechanical system for the SCARA robot for the Internet Nuclear Instrumentation Laboratory (INIL). The research method for making robots begins with a 3D CAD design followed by manufacturing and assembly. Robot control using the Arduino IDE application. Robotic arm testing using stress analysis from Autodesk Inventor software and movement and accuracy testing. The results of the research have successfully designed robotic arms with dimensions of 50.8 cm high, 14 cm wide, and 56 cm long. The robot's work area is 189 cm2, with the farthest range being 30 cm. Keywords: radiation protection, mechanical design, SCARA robot, robotic arm, NPP, INIL

Virtual Laboratories in the Teaching of Mechanical Technology

Abstract The aim of this article is to familiarise the reader with the issue of virtual laboratories and to demonstrate their possible use on a concrete example. This example deals with the use of virtual laboratories in the teaching of mechanical engineering in high schools and universities. The Covid-19 pandemic has led to significant changes in the teaching process and its organisation. In this period, teaching usually took place online, which was implemented using resources such as Google Classroom or MS Teams. This article presents a sample task -a project on which students of the second and third year of study at a secondary technical school are working. The project has an interdisciplinary character, because during its implementation students apply and further develop skills and knowledge from several subjects, namely physics, mechanics, chemistry and CAD design. The project is dedicated to the design of a pulley casting for a steel rope.

Controlling a Below-the-Elbow Prosthetic Arm Using the Infinity Foot Controller

Nowadays there are various prosthetic arm designs in the literature, the market, and CAD design websites, with different shapes, sizes, and degrees of freedom. Only limited options are available for controlling such prostheses. Prosthetic arm users reported muscle fatigue and unreliability when using the market-dominated myoelectric sensors. This work presents the “Infinity Foot Controller” as a new approach to control a five-finger below-the-elbow prosthetic arm with wrist rotation and bending capabilities. This foot control system receives user input from a custom insole and a sensor-controller unit placed alongside the user’s shoe to perform various hand grips, gestures, and/or rotations. To demonstrate the new foot controller, a design of a 3D-printed below-the-elbow prosthetic arm, called the “Infinity Arm”, is presented. This arm is suitable for gripping relatively lightweight objects and making hand gestures. It includes a wrist actuation system that permits 120° wrist rotation and 70° wrist extension and flexion. It also includes a haptic feedback system that utilizes fingertip force sensors to relay a vibratory response in an armband placed on the user’s arm, giving the user a sense of touch. A proof-of-concept model was built to demonstrate the system and a testing procedure was proposed.

On-chip ESD Protection Design Methodologies by CAD Simulation

Electrostatic discharge (ESD) can cause malfunction or failure of integrated circuits (ICs) . On-chip ESD protection design is a major IC design-for-reliability (DfR) challenge, particularly for complex chips made in advanced technology nodes. Traditional trial-and-error approaches become unacceptable to practical ESD protection designs for advanced ICs. Full-chip ESD protection circuit design optimization, prediction, and verification become essential to advanced chip designs, which highly depends on CAD algorithm and simulation that has been a constant research topic for decades. This paper reviews recent advances in CAD-enabled on-chip ESD protection circuit simulation design technologies and ESD-IC co-design methodologies. Key challenges of ESD CAD design practices are outlined. Practical ESD protection simulation design examples are discussed.

Femtosecond Laser Machining of an X-ray Mask in a 500 Micron-Thick Tungsten Sheet.

Femtosecond laser material processing (FLMP) was used to make an X-ray mask in a 500 µm thick tungsten sheet without the use of any chemical etch methods. The laser produced an 800 nm wavelength at a 1 kHz repetition rate and a pulse width of 100 fs. The laser beam arrival at the tungsten sheet was synchronized to a computer numerically controlled (CNC) stage that allowed for motion in the XYZθ directions. The X-ray mask design was made using CAD/CAM software (Alphacam 2019 R1) and it consisted of linear, circular, and 45° angle features that covered an area of 10 mm × 10 mm. A total of 70 laser beam passes at a moderate laser energy of 605.94 J/cm2 were used to make through-cut features into the tungsten sheet. The morphology of the top view (laser incident, LS) images showed cleaner and smoother cut edges relative to the bottom view (laser exit, LE) images. It was found that the size dimensions of the through-cut features on the LE surfaces were better aligned with the CAD dimensions than those of the LS surfaces. The focused laser beam produced inclined cut surfaces as the beam made the through cut from the LS to the LE of the tungsten sheet. The circular features at the LS surface deviated toward being oval-like on the LE surface, which could be compensated for in future CAD designs. The dependence of the CNC processing speed on the thickness of the etch depth was determined to have a third-order exponential decay relationship, thereby producing a theoretical model that will be useful for future investigators to predict the required experimental parameters needed to achieve a known etch depth in tungsten. This is the first study that has demonstrated the capability of using a femtosecond laser to machine through-cut an X-ray mask in a 500 µm thick tungsten sheet with no involvement of a wet etch or any other such supporting process.

Numerical Study for Crashworthiness of FSAE Vehicle Chassis via Biomimetic Approach

In the automotive context, a vehicle’s crashworthiness represents its ability to protect the occupants in case of accidents or collisions. This paper documents the design and topology study process of the prototype FSAE (Formula of Student Automotive Engineers) vehicle regarding the crashworthiness aspect. This project aims to generate design for the chassis of prototype FSAE vehicles through a biomimetic approach to simulate the feasibility of biological systems integration in engineering design. Studies on different biological structures good in compression loading resistance and distribution have been conducted according to the selected biomimicry approach. Quasi-static finite element analysis with dynamic loading analysis was implemented in studying the axial, lateral and bending deformation of the designed chassis concerning the specific energy absorption of the model. The following biomimicry approach has successfully shown potentiality in creating a satisfactory solution for automotive problems. The final chassis of the prototype FSAE vehicle shows specific energy absorptivity of up to 130 kJ/kg upon normal to critical impact conditions. CAD design of the expected prototype is produced, along with the presentation of a scaled-down fabricated 3D model. Considering the performance aspect of the prototype FSAE vehicle, the weight of the vehicle chassis has been successfully minimised by 30.8%.

Koios 2.0: Open-Source Deep Learning Benchmarks for FPGA Architecture and CAD Research

With the prevalence of deep learning (DL) in many applications, researchers are investigating different ways of optimizing FPGA architecture and CAD to achieve better quality-of-results (QoR) on DL-based workloads. In this optimization process, benchmark circuits are an essential component; the QoR achieved on a set of benchmarks is the main driver for architecture and CAD design choices. However, current academic benchmark suites are inadequate, as they do not capture any designs from the DL domain. This work presents the second version of our suite of DL acceleration benchmark circuits for FPGA architecture and CAD research, called Koios. This suite of 40 circuits covers a wide variety of accelerated neural networks, design sizes, implementation styles, abstraction levels, and numerical precisions. These benchmarks include 32 DL designs and 8 synthetic (proxy) benchmarks. The Koios benchmarks are larger, more data parallel, more heterogeneous, more deeply pipelined, and utilize more FPGA architectural features compared to existing open-source benchmarks. This enables researchers to pinpoint architectural inefficiencies for this class of workloads and optimize CAD tools on more representative benchmarks that stress the CAD algorithms in different ways. In this paper, we describe the Koios designs, compare their characteristics to prior FPGA benchmark suites, and present results of running them through the Verilog-to-Routing (VTR) flow using a recent FPGA architecture model. Finally, we present case studies showing how exploration of DL-optimized FPGA architecture and CAD algorithms can be performed using our new benchmark suite.

In Vitro Comparison of Internal and Marginal Adaptation between Printed and Milled Onlays.

Nowadays, milling is still the gold standard for fabricating indirect restorations, but to overcome its disadvantages, there are alternatives, such as 3D printing. This study aimed to compare the gaps between the prepared tooth and milled and printed onlays fabricated with the same CAD design. It also aimed to determine the gap reproducibility across onlays fabricated by 3D printing and milling. A resin tooth was prepared for an onlay. After scanning the preparation, an onlay was designed with proprietary dental software. Next, 22 onlays were milled in a graphene-reinforced PMMA disc (Group 1), and 22 onlays were 3D-printed with a hybrid composite material (Group 2). After that, all fabricated restorations were scanned and superimposed on the scanned prepared resin tooth. Subsequently, a specific software was used to measure the margin, central, and intaglio-located gap between the milled or printed restoration and the preparation. Finally, measurements were compared with a multifactor analysis of variance. The results demonstrated that printed onlays (Group 2) adapted better to the prepared tooth than the milled ones (Group 1) (p < 0.05). The comparison of standard deviations showed the better gap reproducibility of printed onlays (p < 0.05). This study concluded that the printed onlays adapted significantly better to the prepared tooth than the milled onlays. Printed onlays also showed significantly better gap reproducibility.

Optimising degradation and mechanical performance of additively manufactured biodegradable Fe–Mn scaffolds using design strategies based on triply periodic minimal surfaces

Additively manufactured lattices based on triply periodic minimal surfaces (TPMS) have attracted significant research interest from the medical industry due to their good mechanical and biomorphic properties. However, most studies have focussed on permanent metallic implants, while very little work has been undertaken on manufacturing biodegradable metal lattices. In this study, the mechanical properties and in vitro corrosion of selective laser melted Fe–35%Mn lattices based on gyroid, diamond and Schwarz primitive unit-cells were comprehensively evaluated to investigate the relationships between lattice type and implant performance. The gyroid-based lattices were the most readily processable scaffold design for controllable porosity and matching the CAD design. Mechanical properties were influenced by lattice geometry and pore volume. The Schwarz lattices were stronger and stiffer than other designs with the 42% porosity scaffold exhibiting the highest combination of strength and ductility, while diamond and gyroid based scaffolds had lower strength and stiffness and were more plastically compliant. The corrosion behaviour was strongly influenced by porosity, and moderately influenced by geometry and geometry-porosity interaction. At 60% porosity, the diamond lattice displayed the highest degradation rate due to an inherently high surface area-to-volume ratio. The biodegradable Fe–35Mn porous scaffolds showed a good cytocompatibility to primary human osteoblasts cells. Additive manufacturing of biodegradable Fe–Mn alloys employing TPMS lattice designs is a viable approach to optimise and customise the mechanical properties and degradation response of resorbable implants toward specific clinical applications for hard tissue orthopaedic repair.

Antropo: An open-source platform to increase the anthropomorphism of the Franka Emika collaborative robot arm.

Robot-to-human communication is important for mutual understanding during human-robot collaboration. Most of the current collaborative robots (cobots) are designed with low levels of anthropomorphism. Therefore, the ability of cobots to express human-like communication is limited. In this work, we present an open-source platform named Antropo to increase the level of anthropomorphism of Franka Emika-a widely used collaborative robot arm. The Antropo platform includes three modules: a camera module for expressing eye gaze, a light module for visual feedback, and a sound module for acoustic feedback. These modules can be rapidly prototyped through 3D printers, laser-cutters, and off-the-shelf components available at a low cost. The Antropo platform can be easily installed on the Franka Emika robot. The added communication channels can be synchronised with the robot's motions to enhance mutual understanding. All hardware CAD design files and software files are released. The platform can be used to study human-like behaviours of cobots and the effects of these behaviours on different aspects of human-robot collaboration. We demonstrate the Antropo platform in an assembly task in which the Franka Emika robot expresses various human-like communicative behaviours via the added communication channels. We also present two industrial applications in which the Antropo platform was customised for the Universal Robots UR16e.

THE PROCESS OF LOWER LIMB PROSTHESIS CREATION USING CAD DESIGN AND FINITE ELEMENT ANALYSIS

Research objective: The aim of this article is to illustrate how prostheses are made, the significance of strength analyses, and why they are produced in accordance with ISO standards. Methodology: Research methods employed include literature review and analysis of an original research. Main conclusions: CAD design and strength analyses are crucial aspects of creating prostheses as medical devices. Modern technology allows for tailoring the design to a specific case and the patient's needs, considering anatomy and specific functional requirements. Numerical analyses make it possible to identify the most vulnerable elements to potential damage and optimize these areas through geometry modifications, among other factors. Additionally, it is possible to simulate critical conditions in which the designed element may find itself. An essential part of the research is conducting strength analyses according to ISO standards, which precisely specify how they should be carried out and under what load. Successfully passing these stages ensures legal safety for the designer and the possibility of implementing the designed solutions throughout the European Union. Application of the study: Strength analyses allow for predicting the behavior of prostheses under load and real-world usage conditions, which is crucial for patient safety. The use of CAD design enables customization of medical devices to individual patient needs. Originality/Novelty of the study: The presented results provide insights into the prostheses design process. By outlining the creation process and conducting numerical analyses, the complexity of this issue becomes apparent. Designing prostheses requires collaboration among several scientific disciplines, including biomechanics, engineering, medicine, materials science, and computer science.

Tree Architecture &amp; Blockchain Integration: An off-the-shelf Experimental Approach

Temporally sensitive tree modeling and urban park spatially explicit simulation offer advantages to large-scale landscape planning and design, especially in the context of smart applications for virtual parks and forests, while Blockchain technology provides collaborative engineering, data integrity, and information confidence. A proof-of-concept 2.5D tree architecture and Blockchain integration technique (distributed Internet-of-Trees images, “IoTr-images”) was presented as a low-cost metaverse case study that affects the forest monitoring and digital landscape architecture design infrastructures. At the core of the proposed feature-based parametric modeling methodology is a 2.5D tree CAD model composed of two perpendicular 2D tree frames on which recorded tree texture has been assigned. A “Batch command-line programming” technique has been implemented, as a user-defined routine at the top of a commercial CAD platform, to describe the proposed off-the-self method and to create tangible tree-image NFT tokens (Internet-of-Trees-images Blockchain). As important findings were recorded, the add-in planning intelligence, the superior data integrity, and confidence, the offline relaxed error-free CAD design, and the superiority in terms of time and cost compared to traditional 3D tree modeling methods (laser scanning, close-range photogrammetry, etc.); as well as the satisfactory tree modeling accuracy for smart forest monitoring and landscape architecture applications. The proposed 2.5D parametric tree model added new value to the CAD-Blockchain integration industry because a plain “Blockchain/Merkle hash tree” tracks tree geometry growth and texture change temporarily with simple parametric transactions (i.e. controlled hash tree magnification/scaling). So, metaverse functionality (decentralized, autonomous, coordinated, and parallel design; same-data sharing; data validation), modification and redesign ability, and planning intelligence are effectively supported by the proposed technique. Main contributions are regarded as the ability for smart forest distributed surveillance and collaborative parallel landscape architecture design, open-source Web-based educational simulations, as well as the potential for off-the-shelf contractual collaborative frameworks (smart contracts between designers and clients). Stratification based on forest types improved above-ground biomass (AGB) estimation, especially when AGB was greater than 500 Mg/ha, using the proposed “IoTr-images” technique. So, this research provides new insight into AGB modeling and monitoring. Finally, the proposed method’s robustness has been validated by performance evaluation testing.

Reverse Engineering Used to Profile a Gerotor Pump Rotor

In most situations, for the proper design of a gerotor pump, numerous parameters must be taken into account: the pump geometry, the properties of the materials from which the pumps are made (Young’s modulus, Poisson’s coefficient, friction coefficients, etc.), the hydraulic characteristics of the circulated fluids (fluid density, kinematic viscosity, etc.), the working performance of the pump (speed ranges, pressure, flow rate, etc.), with greater or lesser influence on volumetric efficiency, work capacity, or energy consumption. The paper presents a study regarding the inspection of the reciprocally enwrapping surfaces of the gerotor pumps using a three-dimensional measurement technique specific to reverse engineering, which involves 3D scanning of the pump components in gearing movement. The components were measured by means of a specific software (GOM Inspect) and compared, by overlap, with the CAD models made with the help of CATIA software (CATIA V5R21). At the same time, an analytical calculation algorithm was developed for the complementarity of virtual representations. Finally, the advantages of the reverse engineering technique compared to the developed theoretical algorithm and traditional CAD design are presented.