Computer Aided Engineering Techniques Research Articles

A machine learning model for non-invasive detection of atherosclerotic coronary artery aneurysm

PurposeAtherosclerosis plays a significant role in the initiation of coronary artery aneurysms (CAA). Although the treatment options for this kind of vascular disease are developing, there are challenges and limitations in both selecting and applying sufficient medical solutions. For surgical interventions, that are novel therapies, non-invasive specific patient-based studies could lead to obtaining more promising results. Despite medical and pathological tests, these pre-surgical investigations require special biomedical and computer-aided engineering techniques. In this study, a machine learning (ML) model is proposed for the non-invasive detection of atherosclerotic CAA for the first time.MethodsThe database for study was collected from hemodynamic analysis and computed tomography angiography (CTA) of 80 CAAs from 61 patients, approved by the Institutional Review Board (IRB). The proposed ML model is formulated for learning by a one-class support vector machine (1SVM) that is a field of ML to provide techniques for outlier and anomaly detection.ResultsThe applied ML algorithms yield reasonable results with high and significant accuracy in designing a procedure for the non-invasive diagnosis of atherosclerotic aneurysms. This proposed method could be employed as a unique artificial intelligence (AI) tool for assurance in clinical decision-making procedures for surgical intervention treatment methods in the future.ConclusionsThe non-invasive diagnosis of the atherosclerotic CAAs, which is one of the vital factors in the accomplishment of endovascular surgeries, is important due to some clinical decisions. Although there is no accurate tool for managing this kind of diagnosis, an ML model that can decrease the probability of endovascular surgical failures, death risk, and post-operational complications is proposed in this study. The model is able to increase the clinical decision accuracy for low-risk selection of treatment options.

Strength-based design of a sunflower stalk cutter machine design using finite element analysis and experimental validation

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

Variational quantum algorithm based on the minimum potential energy for solving the Poisson equation

Computer-aided engineering techniques are indispensable in modern engineering developments. In particular, partial differential equations are commonly used to simulate the dynamics of physical phenomena, but very large systems are often intractable within a reasonable computation time, even when using supercomputers. To overcome the inherent limit of classical computing, we present a variational quantum algorithm for solving the Poisson equation that can be implemented in noisy intermediate-scale quantum devices. The proposed method defines the total potential energy of the Poisson equation as a Hamiltonian, which is decomposed into a linear combination of Pauli operators and simple observables. The expectation value of the Hamiltonian is then minimized with respect to a parameterized quantum state. Because the number of decomposed terms is independent of the size of the problem, this method requires relatively few quantum measurements. Numerical experiments demonstrate the faster computing speed of this method compared with classical computing methods and a previous variational quantum approach. We believe that our approach brings quantum computer-aided techniques closer to future applications in engineering developments. Code is available at https://github.com/ToyotaCRDL/VQAPoisson.

Optimization Design of a Riser-Drill String Coupling System Based on CAE Techniques

In a riser-drill string coupling system, the drill string extends from platform to downhole, and its exterior tube is divided by mud line into two parts: riser for upside and borehole for downside. Due to such a pipe-in-pipe structure, an improved dynamic model is proposed to take the multipoint interactions between the inner and outer pipes into consideration. The dynamic responses of this system are analyzed by Computer Aided Engineering (CAE) techniques; specifically, it is numerically simulated in Abaqus; then, both the parametric sensitivity analysis and the main effect analysis are carried out in Isight to determine the optimization parameters and the optimization strategy. Moreover, six-sigma algorithm in Isight is applied to simultaneously drive the neighborhood cultivation genetic algorithm (NCGA) to conduct multiobjective optimization and drive the Monte Carlo method to analyze the stability of the obtained optimal solution. Based on the above investigations, a software package is developed via the secondary developments of both Abaqus and Isight. By this way, the optimization design of the riser-drill string coupling system based on dynamic analysis can be conducted effectively and efficiently.

A Comparative Study of Computer-Aided Engineering Techniques for Robot Arm Applications

As systems become increasingly complex, their simulation techniques have to be more accurate and enhanced. Despite the wide use of robotic arms in industries, they still encompass a wide number of complexities. The control of a flexible robot arm driven by a Brushless DC Motor (BDCM) for tracking problems is a great challenge, not only for its complex algorithms but also for its verification process. Robotic systems are designed heterogeneously by combining continuous and event discrete models. Therefore, computer-aided engineering tools have to be enhanced in order to support the verification of the control algorithms. Ensuring definite and rapid simulations is a challenging task for robotic application systems. Although control strategies can be tested using the Matlab/Simulink environment to assess their performance, their verification at a low-level still remains a very difficult task. This paper studies different simulation techniques based on Model In the Loop (MIL), Hardware In the Loop (HIL), and Hardware Software In the Loop (HSIL) on a flexible robot arm driven by BDCM in order to overcome each method's limits, focusing on performance and cost and simulation time reduction. The HSIL achieves the highest accuracy and speed than MIL and HIL and provides reusability and portability of the control unit compared to the other techniques.

Evaluating the efficacy of recombinant human bone morphogenic protein-2 in the treatment of alveolar clefts with autologous bone grafting using computer-aided engineering techniques

Recent studies have indicated the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) to be a viable adjunctive to alveolar cleft reconstruction owing to its osteoinductive capacity. This study aimed to evaluate the efficacy of rhBMP-2 in the treatment of alveolar cleft with autologous bone grafts by precise volumetric analysis. Twenty-six patients (aged 8-14) with unilateral alveolar clefts were enrolled in this comparative study. Patients were divided into two groups: the iliac crest bone graft (ICBG) was placed at the side of the cleft in the control group (ICBG group), and rhBMP-2 was mixed with the ICBG in the rhBMP-2 group (BMP group). Helical computed tomographic images were obtained preoperatively and 12 months postoperatively. The datasets were reconstructed as three-dimensional (3D) images using Mimics software and processed using Geomagic Wrap. The newly formed bone of the alveolar cleft was segmented by identifying the differences between preoperative and postoperative 3D images. In the ICBG group, the volume of newly formed bone ranged from 0.25 to 0.88 cm3, and the mean (SD) bone formation percentage was 42.01% (15.57%). In the BMP group, the volume of newly formed bone ranged from 0.34 to 1.09 cm3, and the bone formation mean (SD) percentage was 55.79% (11.84%). There was a statistically significant difference between the two groups in terms of the postoperative percentage of bone formation (p = 0.022). Thus, rhBMP-2 combined with an autologous bone graft is a promising technique to improve the results of secondary alveolar bone grafting.

Assessment of Bone Formation After Secondary Alveolar Bone Grafting With and Without Platelet-Rich Plasma Using Computer-Aided Engineering Techniques.

The aim of this study was to analyze the newly formed bone volume (FV), 6 months after secondary alveoloplasty using iliac cancellous bone graft, with and without platelet-rich plasma (PRP). Forty patients with unilateral alveolar cleft were involved in this randomized, prospective, comparative study, with 20 patients each forming the control (group A) and PRP (group B) groups, respectively. The preoperative alveolar defect volume (DV) and the postoperative FV were automatically calculated by the computer-aided engineering software using the patients' pre and postsurgical computed tomography data. The volume of the actual bone graft (AV) was identical to the DV calculated before surgery. The bone formation ratio (BF%) was calculated as follows: BF% = (FV/AV) × 100%. The mean BF% was 42.54 ± 9.32% in group A and 46.97 ± 18.49% in group B. There was no statistically significant difference between the 2 groups for BF% (P > 0.05). The study presents a fast and accurate method for assessing the effect of PRP in alveolar grafting. However, the study found no conclusive evidence on the effect of PRP on bone growth.

Verification and validation of detonation modeling

Abstract The mathematical model used to describe the detonation multi-physics phenomenon is usually given by highly coupled nonlinear partial differential equations. Numerical simulation and the computer aided engineering (CAE) technique has become the third pillar of detonation research, along with theory and experiment, due to the detonation phenomenon is difficult to explain by the theoretical analysis, and the cost required to accredit the reliability of detonation products is very high, even some physical experiments of detonation are impossible. The numerical simulation technique can solve these complex problems in the real situation repeatedly and reduce the design cost and time stunningly. But the reliability of numerical simulation software and the serviceability of the computational result seriously hinders the extension, application and the self-restoration of the simulation software, restricts its independently innovational ability. This article deals with the physical modeling, numerical simulation, and software development of detonation in a unified way. Verification and validation and uncertainty quantification (V&V&UQ) is an important approach in ensuring the credibility of the modeling and simulation of detonation. V&V of detonation is based on our independently developed detonation multi-physics software-LAD2D. We propose the verification method based on mathematical theory and program function as well as availability of its program execution. Validation is executed by comparing with the experiment data. At last, we propose the future prospect of numerical simulation software and the CAE technique, and we also pay attention to the research direction of V&V&UQ.

Non-overlapping domain decomposition solution schemes for structural mechanics isogeometric analysis

Isogeometric analysis (IGA) is a novel computer aided engineering technique that addresses diverse problems in computational mechanics [1–4], all under the exact geometric representation. Apart from the exact geometric representation, the high continuity of IGA shape functions enhances the accuracy and robustness of the method. However, the price to pay is that the resulting matrices are denser, with increased bandwidth and overlapping which make the solution of large-scale problems more computationally intensive. As a result, effective solution techniques are still considered an open issue for further research. In this paper, an innovative family of solution schemes based on domain decomposition methods (DDM) is proposed, that significantly reduces the computational cost. Specifically, the solution of the global system is performed with the preconditioned conjugate gradient algorithm (PCG) whose preconditioning step is evaluated with a dual DDM where special care is taken to avoid the overlapped subdomains which are inherent in decomposed IGA formulation due to the increased continuity of the shape functions.

Design and manufacturing of patient-specific orthodontic appliances by computer-aided engineering techniques.

Orthodontic treatments are usually performed using fixed brackets or removable oral appliances, which are traditionally made from alginate impressions and wax registrations. Among removable devices, eruption guidance appliances are used for early orthodontic treatments in order to intercept and prevent malocclusion problems. Commercially available eruption guidance appliances, however, are symmetric devices produced using a few standard sizes. For this reason, they are not able to meet all the specific patient's needs since the actual dental anatomies present various geometries and asymmetric conditions. In this article, a computer-aided design-based methodology for the design and manufacturing of a patient-specific eruption guidance appliances is presented. The proposed approach is based on the digitalization of several steps of the overall process: from the digital reconstruction of patients' anatomies to the manufacturing of customized appliances. A finite element model has been developed to evaluate the temporomandibular joint disks stress level caused by using symmetric eruption guidance appliances with different teeth misalignment conditions. The developed model can then be used to guide the design of a patient-specific appliance with the aim at reducing the patient discomfort. At this purpose, two different customization levels are proposed in order to face both arches and single tooth misalignment issues. A low-cost manufacturing process, based on an additive manufacturing technique, is finally presented and discussed.

Optimum Design of the Spoke Type Load Cell Based on Fatigue Performance

With the improvement in processing level and the quality requirements of parts, fatigue failure has gradually become one of the main failure modes of the spoke type load cell. Combining the requirements of both static strength and fatigue performance based on the computer-aided engineering technique, the maximum equivalent stress and fatigue lifetime of the elastic structure are obtained by changing the dimension of the length, width and height of the spoke, the transition fillet and the inclination angle, which realizes the optimal design of the spoke type load cell. The result provides a valuable reference for the design and development of force sensors for high-cycle fatigue.

Parametric optimization and solidification analysis of grey cast pump adapter castings using DOE and CAE – a case study

Casting defects account great threat to a growing foundry, since it is directly related to the economy. In this work, grey cast pump adapter casting process in a foundry is optimized to produce quality castings using design of experiments (DOE) and Computer aided Engineering (CAE) approaches. Prominent parameters like clay percentage, moisture percentage and mould hardness are considered for performing DOE with three different levels of Box–Behnken Design. Experimental trials were conducted and number of defective components was measured. Results are evaluated using Design Expert Evaluation software to obtain optimal settings. Analysis of Variance test revealed contribution level of each parameter in the casting process. DOE is an efficient tool to optimize casting process that can produce quality castings. In addition, possible defects in castings are analysed using CAE technique (PROCAST simulation software). Simulation using PROCAST is carried out to investigate internal defects by carefully designing gating and feeding parameters in pump adapter castings. Bottom filling is encouraged in the mould cavity to control metal filling process. It can be inferred that DOE and CAE PROCAST simulation has enabled to achieve uniform cooling rate and directional solidification to produce defect free grey cast pump adapter castings.

Multi-stage forging process design of steering system output shaft for reduction of energy consumption

The purpose of this study is to propose a method for reducing carbon emissions produced during the manufacture of output shafts by increasing productivity and reducing energy consumption. To this end, the existing machining process was redesigned as a multistage cold forging process, using a computer-aided engineering technique. The critical parameters considered for the redesigning were material deformation, metal flow, and load. Rigid plastic finite element analysis software DEFORM-2D3D was utilized to identify and analyze these parameters. The derived multi-stage cold forging process was designed on the basis of the test results. It was also verified that the new process substantially increased productivity. A carbon life cycle assessment (LCA) was performed to compare the amounts of carbon emission, material loss and energy consumption of the existing machining process and derived multistage cold forging processes. The comparison results indicated considerably lower carbon emissions, material loss and energy consumption in case of the latter.

Optimal high-rigidity structure design for CNC machine tools using CAE technique

Purpose – For machine tools, the machining performance is mainly determined by the rigidity of the machine structure. How to design a machine tool with high rigidity is always a challenge issue. The paper aims to discuss these issues. Design/methodology/approach – In this paper, the Computer Aided Engineering (CAE) technique is used to analyze the structure rigidity of a Computer-Numerical Control (CNC) turn-mill machining center. The considered structure parameters include static rigidity and vibration mode. Through the integral analyses of these two structure parameters in conjunction with the practical design experiences, an optimal structure is obtained. Findings – Comparisons between the original prototype and the suggested new design structure via CAE technique under the guide of these two stiffness parameters show a great improvement on the maximal deformation of the machine structure under the action of cutting forces. Originality/value – Through the proposed integrative examination of two structural parameters and the CAE technique, together with design experiences, an optimal CNC machine structure can be obtained.

Finite Element Analysis of Precursors to Macroscopic Stick–Slip Motion in Elastic Materials: Analysis of Friction Test as a Boundary Value Problem

In this study, we apply the finite element method to investigate precursor to frictional sliding phenomena arising immediately prior to macroscopic stick–slip transitions in elastic bodies within the framework of a continuum theory. Using a numerical model that mimics an actual experimental system, we study the behavior of contact surface nodes to assess the influence of stiffness, driving velocity, initial conditions, and discretization conditions on the propagation characteristics of microscopic slips. In particular, we show that the initial distribution of frictional stress arising due to the Poisson effect has a significant effect on the propagation characteristics in slip regions. Next, based on the results of a finite element analysis of precursor phenomena that accounts for the influence of bulk compliance, we consider the determination of parameters in rate-dependent friction models. With regard to the behavior of sliding friction, we show that the relationship between friction tests and friction models is fundamentally different from the relationship between material tests and constitutive models for material deformation. We conclude that a proper understanding and classification of friction tests, friction models, and the relationship between these tests and boundary value problems are crucial ingredients in the application of computer-aided engineering techniques to sliding-friction phenomena; indeed, friction tests must ultimately be treated as boundary value problems.

Finite element analysis of the percutaneous coronary intervention in a coronary bifurcation.

The paper presents the process of numerical modeling and simulation of balloon angioplasty of the coronary artery using Finite Element Method. The authors focused on the issue of applying adequate pressure in an arterial tissue during the post-dilatation process in the "kissing balloon" stenting technique applied to patients with bifurcation stenosis. Despite great progress in the field of interventional cardiology, angioplasty in bifurcations still belongs to the most difficult interventions, generally being less effective and more risky than in the cases of straight stenosis. During the modeling procedures and further simulations, the authors focused on mutual cooperation of non-compliant angioplasty balloons and the coronary artery. The other goal was to develop a sufficiently accurate model of the coronary artery fragment, including its bifurcation and angioplasty balloons; however, it was decided to ignore the modeling of coronary stents. The issue undertaken is considered as relatively complicated and complex but, in the authors' opinion, the implementation of advanced computer aided engineering techniques may, in this case, answer several important questions without the need of performing costly and aggravating in vivo tests.

An Overview of Automobile Noise and Vibration Control

In this paper the current state-of-the-art techniques in automobile noise and vibration control are presented. Automobile designers and manufacturers have to pay attention to the global competition of their products, adherence to legislative regulations and passenger/driver comfort while designing an automobile and its components. Designers can take advantage of efficient numerical modeling techniques so that in before the prototype of the automobile is produced, the design can be tweaked and modified by using computer aided models to optimize the design with a target of achieving low noise and vibration levels in the prototype. Here, examples of some typical cases are provided where optimum levels of noise and vibration level are obtained in the design of automobile components using computer aided engineering techniques

The Research of CAE Active Knowledge Aided System Based on Network

According to the application status of the Computer Aided Engineering (CAE) in mechanical design field and the higher knowledge threshold that is set up for designer by CAE technique, this paper puts forward to construct a basic prototype of system to provide knowledge assistance for CAE designer with active knowledge assistance method and operation encapsulation based on network. And it is encapsulated as the partner software of the CAE software to realize the effective utilization of the CAE to reduce the learning burden of designer and designing cost. The existence of this aided system promotes the application of CAE in mechanical design engineering and improves the innovation ability.

Use of FEM and photo elasticity for shape optimization of S type load cell

In modern technological environment, the conventional methodology of design cannot compete the modern trends of computer aided engineering techniques. Continuously the research is going on for new innovative design in the engineering field. To build a highly optimized product is the basic requirement of today's global market. All around efforts were put forward in this direction. Various software professionals and technologies have developed various design packages. It is a challenging task to shape optimize 'S' type load cell with best functional requirements and at lowest weight. In this project an attempt is made to model an 'S' type load cell and optimization of the same using the finite elements analysis software 'ANSYS'. A simple model of 'S' type load cell is considered for FEM modeling and optimization. This paper illustrates the model of 'S' type load cell before optimization and finally obtained optimized model. Using Photo-elasticity technique, results are crosschecked which gives results very close to FEM technique. With the aid of these tools the designer can develop and modify the design parameters from initial design stage to finalize basic geometry of Load Cell.

CUSTOM-MADE BRACKETS FABRICATION BY AN ADDITIVE MANUFACTURING PROCESS FOR ORTHODONTIC TREATMENT

Brackets are basic elements of orthodontic systems. Traditionally, they are produced by a powder-injection mass production process, by which it is difficult to develop individualized products. This study applies computer-aided engineering techniques, including digitizing, virtual model design, and additive manufacturing (AM) to orthodontics for the production of customized brackets. First, a digital model of the teeth was obtained via a 3D scanning process, in which an individual teeth plaster mold was digitized; customized brackets were then designed based on the model, and physical brackets were rapidly fabricated by AM processing. Finally, key dimensional measurements of the brackets were taken to confirm whether the brackets fulfilled the functional requirements for clinical usage. By this process, brackets designed for different teeth pads were obtained by digital planning, CAD design and rapid manufacturing. The custom-made brackets include complete dental profile information, and increase the efficiency of treatment, save clinical setup time, and reduce the treatment duration and cost for the patient. The direct manufacture of metal brackets by an AM process is a modern method with great potential to be used in the generation of customized brackets for orthodontic treatment.