Theoretical Model For Design Research Articles

Research on the classroom teaching design model of enterprise mentors from the perspective of modern apprenticeship

With the advancement of modern apprenticeship, corporate mentors play an increasingly important role in vocational education. However, in the face of new talent training models, corporate mentors face many problems and challenges in classroom teaching design work. This study aims to investigate the problems encountered in the classroom teaching design process for corporate mentors from the perspective of modern apprenticeship. It proposes a classroom teaching design model based on the BOPPPS model that integrates digital technology to solve these problems. This model aims to enhance corporate mentors' teaching design capabilities and classroom instruction quality through digital technology empowerment and optimization of the BOPPPS model. The research results of the paper provide a theoretical, systematic, and scientific classroom teaching design model for enterprise instructors. It provides new perspectives and practical solutions to the classroom instructional design of enterprise instructors under the modern apprenticeship system.

Hybrid rehabilitation of 3D RC beam-column joints using UHP-HFRC and FRP wrapping: Experimental evaluation and theoretical analysis

Beam-column joints are crucial elements in reinforced concrete (RC) structures subjected to seismic loading, as they are vulnerable elements prone to significant damage during earthquakes. Due to extensive structural damage, various methods have been developed to strengthen beam-column joints. However, research on rehabilitation and repair methods has been limited, with most studies focusing on 2-D joints and overlooking the confinement effect of corner beams on the joint core. This study aims to investigate novel hybrid rehabilitation systems, including ultra-high performance hybrid fiber-reinforced concrete (UHP-HFRC) and fiber-reinforced polymer (FRP) systems, alongside embedding reinforcement into heavily damaged 3-D beam-column joints subjected to pre-cyclic loading and subsequent cyclic loading. Parameters related to hysteresis response were obtained and discussed, such as ductility, lateral stiffness, dissipated energy, equivalent hysteresis damping, and pinching ratio of the tested specimens. The experimental findings revealed that utilizing an FRP and UHP-HFRC hybrid rehabilitation system enhanced ductility, dissipated energy, and lateral stiffness of heavily damaged joints by 25 %, 73 %, and 81 %, respectively, compared to the undamaged reference specimen. Additionally, a simplified design model was developed to predict the shear resistance of beam-column joints, incorporating principles of strut-and-tie. The theoretical design model was also validated against the experimental database, demonstrating a good accuracy with MV and COV of 0.97 and 13 %, respectively.

A theoretical model for roller-shape design of three-roller continuous and synchronous calibration process of ovality and straightness for large thin-walled pipes

Large thin-walled pipes are particularly suitable for oil and gas transport and auxiliary pipes in cold areas or deep sea-beds. At present, the rounding and straightening processes are completed independently, and the theoretical model for roller-shape design is analyzed only in a single direction. To solve this problem, a theoretical model for roller-shape design of three-roller continuous and synchronous adjusting straightness and ovality process for large thin-walled pipes is established. The established model is verified by numerical simulation and experimental research using 304 stainless steel pipes. The results show that the three roller-shape design schemes, including three-section, four-section and five-section, proposed based on the theoretical model, can obtain qualified formed pipes. Based on the model, the residual ovality, residual straightness and maximum residual stress of the three roller-shape schemes are discussed. The residual straightness can reach within 0.2%, and the residual ovality can reach within 1%. It verifies the applicability of the model and the feasibility of the process. The model can provide a theoretical basis for presetting the process parameters and optimizing the roller-shape.

The Discussion of the Influence of Eccentricity Ratio on Lubrication Characteristics of Fluid Lubricated Bearings

Abstract: The operating quality of bearings has also led to higher criteria with the growing status of the manufacturing industry in social production. The eccentricity ratio of the bearing system is particularly susceptible to change during operation as a result of the external load, which has a direct impact on the lubricating properties. On the one hand, a reasonable eccentricity ratio will improve the bearing's lubrication performance, increase stability, and better meet processing requirements; on the other hand, it will result in uncontrollable bearing behavior and may even cause the real world to deviate from the theoretical design model. The study aimed to analyze and discuss the current findings on the change in bearing eccentricity ratio. More than 100 related articles have been summarized, and bearing behavior research results, such as lubrication and load-bearing characteristics, are discussed. This paper discusses the progress of research on the eccentricity ratio problem of fluid-lubricated bearings, as well as the effect of eccentricity ratio change on bearing lubrication characteristics for bearings using different lubricating media. Active control measures to mitigate the negative impact of changing bearing eccentricity ratios are also presented. After analyzing and summarizing the relevant literature, it has been found that the eccentricity is one of the important factors affecting the lubrication characteristics of bearings.

Experimental investigation and theoretical modeling on Bernoulli gripper using water for supply power enhancement

Bernoulli gripper is a fluid-driven vacuum suction device, widely used in automated production lines, with suction force regarded as its key mechanical indicator. Previous design methods for optimizing the structure and parameters showed very limited enhancement in suction force due to the compressibility of air, which limits the supply pressure and supply power. Therefore, this study proposes an innovative design for replacing the fluid medium from compressible gas to incompressible liquid (e.g., water). It was experimentally validated that the gripper using water can increase the supply power several times and the suction force dozens of times compared with that using air. Then, the pressure distribution and flow field of the gripper were investigated experimentally, implying that the flow field exists in the water-film zone and the bubble zone, with radial lines of water flow of equal cross section formed in the bubble zone. Furthermore, a model of pressure distribution was established, including the water-film zone, the bubble zone, and the boundary between the two. The theoretical results were basically consistent with the experimental results. This study provides an innovative idea, theoretical model, and experimental data for the optimal design and application of the Bernoulli gripper.

Flexible Couplings Design Management System for Generating Plants

This study has provided a computer programming method of solving the problem of quick design and selection of tyre flexible couplings applied in power generating plants. First, a theoretical design model was developed for tyre flexible couplings by relating transmission power of the couplings to the power ratings and the service factor of generating plant. On this basis, standard coupling sizes, and dimensions were selected at varying speeds, 1000, 2000 and 3000 rpm, from which the best choice of waste tyre coupling was made. Computer software package was developed using python language for robust and quick selection of the best coupling sign for a given power ratings of the generating plant. A case study results showed that for over 16 hours of running the generating plant, the selected service factor (1.5), engine speed (1000 rpm), coupling size (F 60), bore diameters (42-48 mm) and power rating (11.10 kW) performed satisfactorily. Couplings selection results of the five cases obtained from the computer package were consistent with the ones obtained manually. Computer package performed better with time saving of more than 99%. Therefore the system is capable of selecting the best tyre flexible couplings for a given generating plant power operated within the stated (16) hours without recourse to manual design and flexible coupling standards.

Spatial organization of riverside territories in Irkutsk area: mid XX – early XXI centuries

The paper presents a design of a scientifically-based, theoretical model for organization of riverside territories of the Irkutsk area under contemporary conditions. The work set out to analyze the factors influencing the formation of the riverside territories, problems and possible directions for necessary transformations; to systematize and adapt the current theoretical and methodological base; to develop a theoretical design model for spatial organization of the territories. The research methodology involves system and landscape-geographical approaches. Urban ecological analysis of riverside territories included analysis of spatial and strategic planning documents, field investigation of the territories, graphical analysis of world experience in terms of patterns and trends in organizing riverside territories, as well as conceptual modeling with consideration to the urbanization level of the territories. The study consists in developing the following definitions: scientific ground for spatial organization of riverside territories in urban area; global trends in organizing riverside territories in urban area; theoretical design model and perspectives for transformations in the territories. The study results include the development of a theoretical design model for the riverside territories in the Irkutsk area, enabling the growth potential and organization principles of the riverside territories to be effectively identified with consideration to their urbanization level. In addition, the authors offer a definition for the concept of “riverside territories in the urban area.”

Acoustic metasurface for perfect absorption using helmholtz resonators with non-uniformly partitioned cavities by membranes

We propose an acoustic metasurface consisting of sub-wavelength Helmholtz resonators whose cavities are non-uniformly partitioned by membranes, aiming at perfect absorption of low-frequency sound with the aid of hybrid resonance. Compared to the existing unit cells based on Helmholtz resonators, the proposed ones with embedded membranes have lower resonance frequencies, which implies that it is possible to achieve perfect absorption of sound by using a thinner metasurface. This study provides a theoretical model for fast and accurate design considering the visco-thermal losses in narrow orifices and the higher-order modes of the membrane. By optimizing geometrical parameters and locations of the embedded membranes, we design the metasurface for perfect absorption based on the theoretical model. Experimental validation is performed in impedance tube via fabrication.

Trajectory planning method for docking of large aircraft components

PurposeIn the digital assembly system of large aircraft components (LAC), the docking trajectory of LAC is an important factor affecting the docking accuracy and stability of the LAC. The main content of docking trajectory planning is how to move the LAC from the initial posture and position to the target posture and position (TPP). This paper aims to propose a trajectory planning method of LAC based on measured data.Design/methodology/approachFirst, the posture and position error model of the wing is constructed according to the measured data of the measurement points (MPs) and the fork lug joints. Second, the particle swarm optimization algorithm based on the dynamic inertia factor is used to optimize the TPP of the wing. Third, to ensure the efficiency and stability of posture adjustment, the S-shaped curve is used as the motion trajectory of LAC, and the parameters of the trajectory are solved by the generalized multiplier method. Finally, a series of docking experiments are carried out.FindingsDuring the process of posture adjustment, the motion of the numerical control locator (NCL) is stable, and the interaction force between the NCLs is always within a reasonable range. After the docking, the MPs are all within the tolerance range, and the coaxiality error of the fork lug hole is less than 0.2 mm.Originality/valueIn this paper, the measured data rather than the theoretical design model is used to solve the TPP, which improves the docking accuracy of LAC. Experiment results show that the proposed trajectory method can complete the LAC docking effectively and improve the docking accuracy.

Experimental based assessment of formwork pressure theoretical design models for self-compacting concrete

Self-Compacting Concrete (SCC) offers favourable properties which help accelerate the casting time, especially in congested reinforced structures but when casting with SCC uncertainty remains a challenge on the behaviour of its formwork pressure. Researchers have introduced several design models to predict pressure and its behaviour. This research aims to assess the design models that have been reported in the literature. The assessment was carried out through a series of rigorous laboratory tests and the results from the tests served as input for the mathematical model evaluation. Twelve concrete columns with 2 m height were cast in the laboratory to study the effect of varying the input parameters in the existing design models. The formwork pressure was documented by a pressure monitoring system, with the capacity to produce instant results for real-time remote monitoring of the pressure development during and after concrete casting. The formwork pressures were calculated according to the current design models and were compared with pressure data acquitted from the laboratory tests. The results showed that the pressure predicted by the design models was typically greater than the pressure observed during the laboratory tests. The DIN18218 design model showed a relatively close approximation of the pressure distribution over the formwork height and casting time. The limitation of the models is observed when the casting rate varies, and models are sensitive to the input parameters. Thus, additional development of the current design models is needed to enable reliable estimations of the pressure, for example, in the case of low and high casting rates. The laboratory tests also showed that high casting rates and high slump flows generate higher pressures whereas higher thixotropy results in faster pressure reduction during construction.

Performance Analysis and Verification of 14-MeV Fast Neutron Radiography

The ability of 14-MeV fast-neutron radiography (FNR) to inspect bulky objects is evaluated. Both analytical and experimental approaches are used for this purpose. Two important performance parameters—spatial resolution and contrast sensitivity—are theoretically analyzed, especially considering the influence of scatter background and noise. The effect of detection quantum efficiency (DQE) on contrast sensitivity of FNR systems is discussed in this article. To verify the results, film-based neutron radiography experiments were performed using a high-intensity D-T neutron source. Iron samples of varying thickness and containing different detectable structures were used. The visibility and detection capability of the objects were compared with corresponding theoretical results. The results show that the spatial resolution is 0.6 mm and the contrast sensitivity is 2.9 mm for a 3-cm-thick sample. The experiments are in good agreement with theoretical results. This provides a theoretical model for fast-neutron system design and performance evaluation.

Application of Open Building Theory in the Regeneration of Old Residential Building

This research is based on the refinement and diversification demand of housing stock quality improving in China. The paper focuses on the complexity of built environment in old residential areas, which involves numerous responsibilities and rights and multi-role cooperation in the process of regeneration. This paper studies the application of open building theory and its derivative theories in the area of housing regeneration, researches the current situation of policies, mechanisms and design methods for the regeneration of old residential areas in China and discusses the theoretical applicability of open building theory in the design practice of old residential building renewal methods in China. The study investigates the situation of the old residential areas in renovation, divides the responsibility and right relationship between the participants and building components by levels, and establishes a localized theoretical model for the regeneration strategy design of the old residential buildings in China. This study will provide scientific theoretical support for the constructing of a sustainable mechanism involving professional decision-making, long-term management and capital introduction, for the build of a multi-dimensional quality improving regeneration of the old residential areas in China.

Seismic resilient steel substation with BI-TMDI: A theoretical model for optimal design

The based-isolation with tuned mass damper inerter (BI-TMDI) is utilized to enhance the seismic response of steel High-voltage substation switches mounted on frame (SMF). An analytical model with three degree-of-freedom was explored for the optimization analysis and seismic design. Firstly, the displacement variance of this SMF-BI-TMDI system in the whole frequency spectrum was obtained, using statistical Cauchy's residue theorem, which provides an explicit expression of the optimization objective function. Further, a comprehensive parametric analysis was performed, covering a wide spectrum of influential factors. Subsequently, the effectiveness of the proposed analytical model was confirmed by time history response analysis of prototype structures subjected to an ensemble of earthquake motions. The model was also compared with conventional analytical models for structural seismic optimization, showing obviously improved accuracy. This innovative control method and optimization analysis in BI-TMDI enlighten its potential with enhanced vibration control effect for protection of steel substation under earthquake motions.

Multiple interference theoretical model for graphene metamaterial-based tunable broadband terahertz linear polarization converter design and optimization.

Terahertz (THz) polarization converters often working as modulators and switches have many applications in THz sensing, imaging and communication, but many of them still suffer from low polarization conversion efficiency, fixed and narrow polarization conversion band, and low output polarization purity, which are mainly due to the lack of theoretical model for THz polarization converter design and optimization. In order to solve the problem, we adopt multiple interference theory to successfully design and optimize a graphene metamaterial-based tunable broadband THz linear polarization converter: it achieves polarization conversion ratio (PCR) over 0.97, polarization azimuth angle of almost ±90° and rather low ellipticity within a broad polarization conversion band of 1.25 THz; and additionally, its polarization conversion band can be actively tuned by adjusting the graphene chemical potential and almost insensitive to the incident THz radiation angle below 50°. Considering the high performance of the optimal graphene metamaterial-based tunable broadband THz linear polarization converter, this work provides an optimal design offering a way in high-quality manipulation of THz radiation polarization; but more importantly, delivers a theoretical model for tunable THz polarization converter design and optimization.

Online detection of part size based on laser contour scanner

In aerospace die manufacturing, the processing quality of the processed workpiece is an important guarantee for the quality of the final product. Traditional detection methods have high labor intensity and low efficiency. Visual detection can only detect width, not depth information. Based on this, this paper proposes a non-contact laser scanning point cloud processing quality online detection method, through the laser contour scanner to obtain the actual machining parts of the surface point cloud information, and then in the Geomagic Control environment of the actual manufacturing parts point cloud information and Solid Works theoretical design model comparison analysis. Thus, the manufacturing error of the actual manufacturing parts can be obtained, which provides a fast and accurate judgment method for the quality control of the product manufacturing.

A New Method for Reducing Collapsibility of Loess Foundation with Thicker Deposit: The Borehole Preimmersion Method

At present, there are some key issues in the traditional preimmersion method for reducing the collapsibility of the loess ground, such as the difficulty in determining the total water consumption and the long immersion time. In response to these issues, a new method, the borehole preimmersion method, is presented, and a specific theoretical design model is proposed for application in projects. The method is specifically discussed from a new perspective, and the diffusion mechanism and evolution law of water in the ground are presented in detail through theoretical analysis and numerical calculation, respectively. The water diffusion is a mushroom‐type form for a single water injection hole immersed in water. A calculation model derived for a single water injection hole or a group of water injection holes based on the research results is used to calculate the volumes of soaked loess and the total water consumption. Through an in situ immersion test, the treatment effect of this method is evaluated to verify the rationality of the method and the theoretical calculation model proposed in this study, which provides a new method and theoretical framework for effectively reducing the collapsibility of the loess ground.

Design and Implementation of “AugMedicine: Lung Cases,” an Augmented Reality Application for the Medical Curriculum on the Presentation of Dyspnea

Introduction: Augmented Reality is a technique that enriches the real-life environment with 3D visuals and audio. It offers possibilities to expose medical students to a variety of clinical cases. It provides unique opportunities for active and collaborative learning in an authentic but safe environment. We developed an Augmented Reality application on the clinical presentation of shortness of breath (dyspnea), grounded on a theoretical instructional design model. Methods: A team of various stakeholders (including medical teachers and students) was formed to design the application and corresponding small group learning session, grounded on principles of instruction as described by Merrill. Evaluation was performed by an explorative questionnaire, consisting of open and closed questions (Likert scales), covering user experience, content and physical discomfort. Results: Multiple interactive cases of dyspnea were designed. The application plays back audio samples of abnormal lung sounds corresponding to a specific clinical case of dyspnea and displays a 3D model of the related pulmonary pathologies. It was implemented in the medical curriculum as an obligatory small group learning session scheduled preceding clinical clerkships. Prior knowledge was activated prior to the learning session. New knowledge was acquired with the application by solving an authentic problem based on a real patient case. In total 110 students participated in the study and 104 completed the questionnaire. 85% of the students indicated that the virtually auscultated lung sounds felt natural. 90% reported that the augmented reality experience helped them to better understand the clinical case. The majority of the students (74%) indicated that the experience improved their insight in the portrayed illness. 94.2% reported limited or no physical discomfort. Discussion: An Augmented Reality application on the presentation of dyspnea was successfully designed and implemented in the medical curriculum. Students confirm the value of the application in terms of content and usability. The extension of this Augmented Reality application for education of other healthcare professionals in currently under consideration.

A novel calibration method for ball joint position in a posture adjustment system

In posture adjustment systems for large components of aircraft (LCA), composed of several numerical control locators (NCLs), the position deviation of the ball joint (BJ) connecting the LCA to the NCL is an important factor affecting the adjustment accuracy of LCA. Due to manufacturing and installation errors, it is impossible to calculate the precise position of the ball joint center (BJC) relative to the LCA via theoretical design models. To address this problem, a novel calibration method of the BJC position is proposed in this paper. Firstly, the influence of the position deviation of the BJC on the posture adjustment precision of the LCA is studied. Secondly, the calculation model of the BJC position is established in accordance with the relationship between the Z-axle displacement of the NCL and the position and posture variation of the LCA after each NLC rise. Thirdly, based on this model, the uncertainty of the BJC calibration is analyzed by Monte Carlo simulation. Finally, a simulated posture adjustment system, built in the laboratory and the BJC position is calibrated, using the method of force-position hybrid control (FPHC). The experimental results show that, compared with the conventional calibration method, the method proposed in this paper can calibrate the BJC position more accurately, and can greatly improve the precision of posture adjustment.

Tensile behavior of the connection between nut-free high-strength bolt and endplate

Nut-free high-strength bolt permits easy installation and has been widely used in the connection between the column and the corner fitting in assembled-type light steel modular house. 33 specimens were tested under static tension to study the tensile behavior of the connection between the nut-free high-strength bolt and the endplate. The pivotal parameters considered in this experiment include the diameter of the high-strength bolt, the material property of the high-strength bolt, the length of the high-strength bolt, the material property of the endplate, and the thickness of the endplate. The tensile behavior and failure mode of the connection were evaluated and discussed based on the test results. A three-dimensional nonlinear finite element model (FEM) was established by the general-purpose finite element software ABAQUS and validated against the test results. The tensile capacity and failure mode are in good agreement with the test results and the FEM can be adopted for the analysis of the tensile behavior of the connection. The key parameters that influence the tensile capacity of the connection were the diameter, material property and length of the bolt. Whereas, the thickness and material property of the endplate have less influence. Furthermore, the simplified computation formulas were derived and a theoretical design model was established. The design model was verified by comparing the theoretical results with the test ones. It indicates that the design model can well predict the tensile behavior of the connection, which will provide useful references for the design of the connection.

Gravity compensation design of Delta parallel robots using gear-spring modules

This paper presents the gravity compensation for Delta parallel robots by adding a gear-slider mechanism with a compression spring, namely the “gear-spring module,” onto each robot leg. The major significance of the proposing design is that it suggests a compact mechanical solution for gravity compensation of the Delta robot without a compromise of the compensation performance and the robot workspace. The design parameters are determined to approximate the theoretical perfect balancing at a set of targeted configurations. Torque- and energy-reduction criteria are employed to evaluate the performance of gravity compensation. Design examples are implemented through a theoretical design model and a real industrial Delta robot, the FANUC M-3iA/12H. For the theoretical design model, the motor torques of the robot can be effectively reduced within 86 percent of its kinematic workspace. For the industrial Delta robot example, the theoretical peak torque and energy consumption are decreased by up to 38.4% and 55.4% for a pick-and-place task, for which a 10-kgf moving platform is traveling within a range of 1.32 m and a varying speed between 0 and 0.72 m/s. Last, a comparison between the uses of the gear-spring modules, torsion springs, and tension springs for gravity compensation is provided.