Structural Design Models Research Articles

Structural Design and Penumbra Analysis of Dynamic Multi-leaf Collimator Leaf End

Dynamic multi-leaf collimator, which has the function of radiation beam shaping, is a key executive component of tumor precise radiotherapy, and plays a core role in improving the accuracy, efficiency and quality of radiotherapy. A new type of collimator leaf end structure with circular arc and plane combination was studied, and collimator penumbra performance analysis model combining analytical expression and graphic analysis was developed. The influence of leaf end structure on penumbra was analyzed quantitatively, and a set of three-dimensional structure design of dynamic multi-leaf collimator was completed. The feasibility of the structural design and analysis model was verified through experimental measurements.

Finite element analysis of a customized implant in PMMA coupled with the cranial bone

This computational study investigates the effect of the Von Misses stresses and deformations distribution generated by coupling a customized cranial implant with its fixation system for anchoring in the cranial bone of a specific patient. Three simulations were carried out under static loads, in different areas of the implant and during the rest-activity; and another three simulations were considered preset maximum intracranial pressures. Anatomical models were obtained by computed tomography. The design of the device to be implanted was carried out by applying reverse engineering processes, from the corresponding computer-aided design (CAD) model of the bone structure of interest. Likewise, the anchoring system was modeled in detail. Loads were applied at three points on the custom implant. The stress distribution on the artificial plate and the implant-natural bone interface was analyzed. The distribution of the stresses caused by the internal load states on the plate and the anchoring system was also studied. The neurocranial reconstruction with the customized polymethylmethacrylate (PMMA)-based implant and the finite element analysis demonstrated that the fixation and coupling system of the bone-implant interface guarantees adequate protection for the internal structures of the restored area. In addition, the custom-designed and placed implant will not cause non-physiological harm to the patient. Nor will failures occur in the anchoring system.

A bioinspired discrete heuristic algorithm to generate the effective structural model of a program source code

When the source code of a software is the only product available, program understanding has a substantial influence on software maintenance costs. The main goal in code comprehension is to extract information that is used in the software maintenance stage. Generating the structural model from the source code helps to alleviate the software maintenance cost. Software module clustering is thought to be a viable reverse engineering approach for building structural design models from source code. Finding the optimal clustering model is an NP-complete problem. The primary goals of this study are to minimize the number of connections between created clusters, enhance internal connections inside clusters, and enhance clustering quality. The previous approaches' main flaws were their poor success rates, instability, and inadequate modularization quality. The Olympiad optimization algorithm was introduced in this paper as a novel population-based and discrete heuristic algorithm for solving the software module clustering problem. This algorithm was inspired by the competition of a group of students to increase their knowledge and prepare for an Olympiad exam. The suggested algorithm employs a divide-and-conquer strategy, as well as local and global search methodologies. The effectiveness of the suggested Olympiad algorithm to solve the module clustering problem was evaluated using ten real-world and standard software benchmarks. According to the experimental results, on average, the modularization quality of the generated clustered models for the ten benchmarks is about 3.94 with 0.067 standard deviations. The proposed algorithm is superior to the prior algorithms in terms of modularization quality, convergence, and stability of results. Furthermore, the results of the experiments indicate that the proposed algorithm can be used to solve other discrete optimization problems efficiently.

Efficient optimization of parallel micro-channel heat sinks based on flow resistance network model

Electronics cooling is a critical issue affecting technological development. Parallel micro-channel heat sink (PMCHS) is widely applied for electronics cooling. However, the existing optimization methods are incapable to perform efficient design of three-dimensional liquid-cooled PMCHSs, impeding the thermal management of high power and volume-shrinking electronics. In this study, a flow resistance network (FRN) model is developed for structural optimization of three-dimensional liquid-cooled PMCHSs. Based on the uniform flow rate distribution, the FRN model is used to determine the optimized parallel channel widths and the optimized inlet deflector shape of the PMCHS. With the optimized parallel channel widths, the maximum temperature (Tmax) of the PMCHS is decreased by 4.0 K and the temperature standard deviation (σT) is decreased by 20%. With the optimized inlet deflector shape, Tmax and σT are reduced by 4.8 K and 14% respectively. The optimization method based on the developed FRN model for structural design of PMCHSs avoids multiple iterations of system parameters in existing optimization methods, showing its potential in high efficient thermal management of electronics.

Determination of the temperature-dependent thermophysical properties of polymeric foams using numerical inverse analysis

Polymeric foams used as core materials of sandwich panels undergo severe degradation under high temperatures, making the experimental measurement of their thermophysical properties (thermal conductivity and specific heat) possible only up to 150 °C–200 °C. However, their knowledge at higher temperatures is needed to fully understand their behaviour and to develop advanced numerical models for analysis and design of sandwich structures subjected to fire. This work presents a numerical inverse analysis procedure to determine such effective properties for rigid polyurethane (PUR) and polyethylene terephthalate (PET) foams. Firstly, the campaign used to obtain experimental results is presented and then the proposed numerical inverse analysis procedure is described. This is based on the minimization of a least squares functional and a nonlinear finite element thermal analysis. Next, the numerical results and the effective thermophysical properties obtained for both foams are presented and discussed, and are validated by extending their use to the simulation of the thermal response of a sandwich panel subjected to a standard fire. It is concluded that the numerical procedure is capable of estimating the temperature-dependent effective thermal conductivity and specific heat of PUR and PET foams for temperatures well above those corresponding to their decomposition.

Pressure Evaluation of Seamless Yoga Leggings Designed with Partition Structure

Abstract It is a novel approach to design the partition structure of clothing according to the deformation of the human body surface skin during exercise. The functional evaluation of these products remains unknown, and there is limited knowledge about the effects of the partition structure design on the pressure comfort of clothing. This research carried out a partitioned structural design of the leggings based on the skin deformation of the lower limbs of the human body during yoga exercise and developed two styles of seamless yoga leggings. The skin pressure exerted by the new seamless yoga leggings was compared with two commercial yoga leggings. Eight female college students were invited to wear all the yoga leggings samples and perform yoga exercises. The skin pressure exerted by yoga leggings was measured by the German novel-Pliance multipurpose pressure distribution measurement system on 10 body positions. The results showed that yoga leggings designed with a partitioned structure exert a comfortable pressure on the skin during yoga exercise, and the pressure change was smaller under different yoga postures, which has better pressure stability. The partition structure design model of seamless yoga leggings was optimized, which provided a reference for the functional partition design and product development of seamless yoga leggings.

Generative design of de novo proteins based on secondary-structure constraints using an attention-based diffusion model

We report two generative deep learning models that predict amino acid sequences and 3D protein structures based on secondary structure design objectives via either overall content or per-residue structure. Both models are robust regarding imperfect inputs and offer de novo design capacity as they can discover new protein sequences not yet discovered from natural mechanisms or systems. The residue-level secondary structure design model generally yields higher accuracy and more diverse sequences. These findings suggest unexplored opportunities for protein designs and functional outcomes within the vast amino acid sequences beyond known proteins. Our models, based on an attention-based diffusion model and trained on a dataset extracted from experimentally known 3D protein structures, offer numerous downstream applications in conditional generative design of various biological or engineering systems. Future work may include additional conditioning, and an exploration of other functional properties of the generated proteins for various properties beyond structural objectives.

Stress-strain curves for wire arc additively manufactured steels

Interest in the use of wire arc additive manufacturing (WAAM) in construction has increased rapidly in recent years. Key to facilitating wider application is an improved understanding of the material behaviour. In particular, with structural design by finite element analysis in mind, constitutive models to describe the full range stress-strain response of WAAM steels are needed; development of such models is the focus of the present study. WAAM normal-strength steels generally exhibit a stress-strain response featuring a well-defined yield point, a yield plateau (for machined material) or slightly inclined yield plateau (for as-built material) and subsequent strain hardening, while the stress-strain response of WAAM high-strength steels is typically rounded, with no distinct yield point or plateau. This behaviour is similar to that of conventionally-produced steels, and hence can be represented analytically using existing material models, but with suitable modifications — a quad-linear or bilinear plus nonlinear hardening model and a two-stage Ramberg-Osgood model are proposed for WAAM normal- and high-strength steels, respectively. Predictive expressions or standardised values for the input parameters required in the models are developed and calibrated against a comprehensive database of WAAM steel coupon test results collected from the literature. The experimental database comprises over 600 engineering stress-strain curves and covers different feedstock wires, surface finishes (i.e. machined and as-built), material thicknesses, directions of testing and printing strategies. The proposed material models are shown to accurately predict the full stress-strain curves of WAAM steels, and are considered to be suitable for incorporation into analytical, numerical and design models for WAAM steel structures.

The stress state analysis of lattice tower support for 330 kV overhead line using the “USL” software package

In conditions of market economy, overhead power transmission line (OPTL) support structures must be low-cost and of guaranteed quality, the manufacture of which will require a minimum amount of steel. Therefore, it is necessary to improve overhead line supports, which is possible by clarifying the forces in the support elements and when designing using numerical methods. In this article, a mode of deformation of a corner dead-end support of OPTL is analysed, which is considered a spatially multiple indeterminate open system with flexible joints. Attention is given to the basic problems that can occur in setting initial parameters and constructing design models for such structures. There are a number of problems connected with a refined specification of internal longitudinal stresses in the components of an OPTL structure. In designing, the joint operation of the lattice components of the support spatial pattern model is analysed, and the inclusion of stiffening diaphragms and diagonal element members in the operation on all four faces is taken into account. On the basis of the design and the extension of the results, the internal forces obtained and the ones specified in the components of the pattern OPTL support on the similar values of loads were thoroughly compared. When calculating the spatial model of an anchor-corner support as a result of the joint work of lattice elements, a decrease in internal forces in the elements of the spatial model is observed on average by 6.8%, compared to the forces determined in a typical overhead line support from the same load values. It has been established that it is quite acceptable to calculate overhead line lattice structures in the USL software package since the error in determining the forces in the rods is within 2% and the computer time consumption is less than in other software packages.

Adopting a fiber macroelement for accounting the SSI effect in nonlinear seismic analysis

The main purpose of this paper is to propose a practical approach for considering the soil - shallow foundation - superstructure interaction effect in nonlinear seismic analysis. Soil structure interaction is a complicated task dealing with various engineering problems. Taking into account the soil structure interaction extends beyond the numerical analysis, geotechnical investigation, or structural design fields. The artistry of considering the soil structure interaction effect lies in the balance between incorporating soil conditions and the superstructure into one collective model. Following this methodology alongside classical soil mechanics principles provides additional confidence to the structural engineering society in adopting a complete practical concept. The herein presented study introduces a fiber macroelement that represents the soil beneath shallow foundations. This allows for the direct utilization of the fiber macroelement in nonlinear pushover and dynamic analysis in commercial software, as well as its simple implementation in open software systems. The introduction of a procedure for forming the stiffness matrix of the element and a hysteresis soil model is also a key component. Special attention is devoted to obtaining the material backbone curve through experimental results and Eurocode 8?s procedures. Furthermore, this paper demonstrates the implementation of a macroelement for considering the soil-structure interaction effect in nonlinear seismic analysis within commercial software. The primary aim is to provide structural designers with a streamlined approach for incorporating soil conditions into superstructure analysis. Numerical analysis results from an example building with a reinforced concrete structure in commercial software highlight the significance of not underestimating soil conditions. This work emphasizes that relying solely on fixed models in everyday structural design could lead to dangerous and unexpected consequences.

Design and optimization of a novel supersonic rocket with small caliber

<p style='text-indent:20px;'>It's difficult to meet the design requirements of a rocket with sensitive parameters using the traditional methods. This paper develops a design and optimization concept for a lightweight solid-propellant rocket with a small caliber and a high Mach number. The structural design and numerical modeling depend on the interior ballistic methodology. The model is validated by comparing pressure-time data from simulation and experiment. A modified evolutionary algorithm with constraints is applied because of the interactive design parameters and conflicting objects. The launch performance is improved by single- and multi-objective optimization. Under unchanged interior ballistic performance conditions, the peak pressure is reduced by 46.4%, and the erosive peak ratio is reduced by 46.4%. Despite the constraints, the Mach number is improved by 4.9%, the total impulse is improved by 6.3%, the peak pressure is reduced by 92.5%, and the erosive effects are reduced by 38.1% using different optimal solutions. A Pareto front is obtained by a constrained NSGA-Ⅱ, which reveals non-linear and non-uniform relations among design objects. A tidying method is proposed for a clear Pareto front. It indicates that, despite the sensitive parameters, launch safety and higher velocity are possible. The results help designers choose the best design schemes.</p>

Automated BIM-based structural design and cost optimization model for reinforced concrete buildings

The process of optimizing building designs requires developing several architectural and structural layout alternatives. Traditionally, limited number of design iterations can be conducted manually, which is time consuming and results in non-optimum designs in terms of limited functionality or high costs. The goal of this research is to develop an advanced Building Information Modeling (BIM) model for automating and optimizing design of building layouts and structural elements to reach minimum construction cost while abiding by the functionality constraints of the architectural design. The developed model integrates concepts from structural design, BIM modeling, and computer programming into one advanced optimization framework. The model was tested and validated in 11 case studies and is found to reduce the structural materials cost by up to 15% per floor without compromising the defined space requirements.

Structural Design and Spatial Geometric Error Modeling of the Machine Tool for Implant Denture

Implant denture is the most essential method of oral repair, and its processing depends heavily on the precision machining center. Most special denture machine tools do not take into account the requirement of automatic machining of parts. During processing, the parts need to be double-clamped, which changes the geometry of the parts. In this paper, a small special machine tool with seven axes has been developed to realize the automatic processing of implant dentures. Firstly, the processing technology of implant dentures is introduced, and the function of a special machine tool is analyzed. Then, the mechanical structure of the machine tool is established. It has seven moving axes and two cylinders, with the capability of five-axis linkage and combined turning and milling. Uniquely, it has a backside machining unit, which allows the entire automated machining process to be completed after only one clamping. The topological movement chain of the machine tool under different working modes is introduced emphatically. The results show that the machine structure can satisfy the automatic machining process of denture parts. Meanwhile, the spatial geometric error model under each topology is established, which provides a theoretical basis for the error compensation of the machine tools.

Bending Study of Six Biological Models for Design of High Strength and Tough Structures.

High strength and tough structures are beneficial to increasing engineering components service span. Nonetheless, improving structure strength and, simultaneously, toughness is difficult, since these two properties are generally mutually exclusive. Biological organisms exhibit both excellent strength and toughness. Using bionic structures from these biological organisms can be solutions for improving these properties of engineering components. To effectively apply biological models to design biomimetic structures, this paper analyses strengthening and toughening mechanisms of six fundamentally biological models obtained from biological organisms. Numerical models of three-point bending test are established to predict crack propagation behaviors of the six biological models. Furthermore, the strength and toughness of six biomimetic composites are experimentally evaluated. It is identified that the helical model possesses the highest toughness and satisfying strength. This work provides more detailed evidence for engineers to designate bionic models to the design of biomimetic composites with high strength and toughness.

Self-Exfoliation of Flake Graphite for Bioinspired Compositing with Aramid Nanofiber toward Integration of Mechanical and Thermoconductive Properties

HighlightsA self-grinding exfoliation strategy that depends on mutual shear friction between flake graphite particles is successfully developed to prepare pristine graphene with largely enhanced yield and productivity.Bioinspired assembly of pristine graphene nanosheets to an interconnected aramid nanofiber network is achieved by a continuous sol-gel-film transformation strategy and generates a flexible yet highly thermoconductive film.Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices. Herein, we report a bioinspired nanostructured film with the integration of large ductility and high thermal conductivity based on self-exfoliated pristine graphene and three-dimensional aramid nanofiber network. A self-grinding strategy to directly exfoliate flake graphite into few-layer and few-defect pristine graphene is successfully developed through mutual shear friction between graphite particles, generating largely enhanced yield and productivity in comparison to normal liquid-based exfoliation strategies, such as ultrasonication, high-shear mixing and ball milling. Inspired by nacre, a new bioinspired layered structural design model containing three-dimensional nanofiber network is proposed and implemented with an interconnected aramid nanofiber network and high-loading graphene nanosheets by a developed continuous assembly strategy of sol–gel-film transformation. It is revealed that the bioinspired film not only exhibits nacre-like ductile deformation behavior by releasing the hidden length of curved aramid nanofibers, but also possesses good thermal transport ability by directionally conducting heat along pristine graphene nanosheets.Graphical abstract

МЕТОДОЛОГИЧЕСКИЕ АСПЕКТЫ ПРОЕКТИРОВАНИЯ ЦИФРОВОЙ МОДЕЛИ ПРОЦЕССА ДВУСТОРОННЕЙ ТОРЦЕШЛИФОВАЛЬНОЙ ОБРАБОТКИ

The paper is devoted to the development of methodological foundations of digital models of two-sided face grinding treatment. The study objective is further increase in the effectiveness of work preparation of two-sided face grinding in the conditions of automated and digital manufacture. At the present stage of the development of mechanical engineering and computerized manufacture the technological parameters of adjustment and cutting modes of metalworking systems should be determined not by reference data, but as a result of simulation modeling of treatment processes taking into account all actual technological factors of influence. The problem to which the paper is devoted is the search for solutions to the problems of ensuring the correctness of mathematical and computer models being developed, adequate consideration of dominant factors, correct representation in the digital form of treatment process of patterns, relationships and constraints taking place based on the methods of structural parametric analysis and simulation modeling. These problems can be solved only on the basis of a systematic approach to the treatment and the development of methodological foundations for creating its digital model, which is the subject of research in the presented paper in relation to two-sided face treatment (FT). The following things are proposed: an algorithm of structural and parametric FT design, a structural and functional model of workpiece forming, objects and connections of technological interaction in FT, which together are the methodological foundations for the virtual FT presentation and have signs of scientific novelty. The results of virtual FT of cylindrical rollers in production conditions and the technical settings of the machine found on the basis of the stated methodological recommendations show that the required values of the dominant shape errors and the relative position of the treated surfaces are provided within the specified constrains. Conclusions: the provisions given in the paper and the model environment can be used in the development of an automated system for technological FT preparation in the conditions of digital production.

A paper-based self-inductive folding displacement sensor for human respiration and motion signals measurement

Flexible sensors have recently attracted much attention for potential applications in motion measurement and wearable health monitoring. In this paper, an environment-friendly, economic, and high-performance paper-based self-inductive folding displacement sensor (PSIFS) was proposed, with displacement resolution of 20 μm and wide measurement range of 43.2 mm. The sensor sensitivity could reach 4.44% mm−1 with the maximum deviation of 0.00904 in experiments. The sensing mechanism based on inductance variation due to three-dimensional deformation of planar inductor coil and structural design principle under two dimensions of sensitivity and size were proposed and studied. The folding method to enhance sensitivity was proposed and 3 times sensitivity enhancement could be achieved by once folding. Multiple breathing states and motion states of the human joints could be recognized. The proposed simple paper-based sensor, folding method to increase sensitivity, and structural design model may provide a way for the research of flexible sensors.

The Construction Technology of Freeform Surface Spatial Bending-Torsion Steel Structure

Taking the construction project of the National Cybersecurity Talents and Innovation Base as an example, this paper studies the construction technology of freeform surface spatial bending-torsion steel structure based on structural design model transformation, including the parametric modeling of deepening design model, computer-aided bending and torsion frame production, flexible docking in the bending-torsion combination unit, and welding stress deformation, in hope to provide reference for similar projects in the future.

Information System for Supporting the Process of Protected Voting

The authors of the article have developed methodological grounds, designed and constructed an information system to implement protected voting. The analysis of the main ways of using information technology in voting area has resulted in the finding that mobile devices with certain software can significantly reduce the number of visits to polling stations, which make political voting much more accessible to people. The authors have designed the information system using a structural approach and design model Data Flow Diagrams (DFD). They have also developed a context diagram of the information system and decomposed its main process to demonstrate ways to convert input into output. Algorithm of work have been presented in the form of a Petri net, also the authors have specified on the tables of positions and transitions of this network for a better understanding of system features. The functional purpose has been presented, the analysis of software tools has been done that allows us to achieve the set goals in designing the system. Verification of work has been carried out which is proved in screenshots of program windows of the system and contents of the main pages has also been described.

Classification of Infilled Shells Structures Considering Soil-Construction Interaction

The paper examines retaining structures consisting of thin shells filled with soil or other material (in a varying degree providing structural integrity), keeping the soil from failure and sustaining the complex of technological loads. Filled shells structures serve as a constructive base for retaining structures and are used in various construction areas (industrial, transport, hydraulic engineering). The technique is proposed which allows to determine structural design model at an early design stage considering the key initial design parameters: overall dimensions of the structure, acting loads and the soil base properties. Based on the proposed ratios an example is given of the structure classification and the design model choice depending on its dimensions, depth of embedding and the magnitude of soil base design resistance. Extreme principal dimensions ratios of the structure are shown at which there is a need of fixing the structure in the soil, dependencies for determining setting depth are given.