Computer-aided Design Drawings Research Articles

ANALYSIS OF MICRO GAS TURBINE PERFORMANCE USING MODELLING APPROACH

Micro-gas turbine (MGT) is compact and self-sufficient distributed power generation units that exhibit reliability and has the capability to mitigate carbon monoxide (CO) emissions while conserving energy together with biomass used as a fuel sources. It is expected that they will have a noteworthy impact on securing the provision of upcoming energy resources for isolated areas, disaster condition and off-grid zone regardless of their connection to the power grid. However, the MGT performance using the various fuel still questionable. Databases and procedure of the MGT performance analysis should be established well to understand the overall MGT performance. In this study, MGT performance is determined by utilising the computer aided design (CAD) and solver software such as SOLIDWORKS and ANSYS-FLUENT. CAD drawing is used to design the combustion chamber and simulation performance is visualised in specific inside the combustion chamber (CC) of the MGT. The solver software was employed for the purpose of conducting computational fluid dynamics (CFD) analyses. The optimal configuration contained a flame holder with a diameter of 50 millimetres, a chamber height of 60 centimetres, four holes with diameters of 6, 8, and 10 millimetres, and a dead zone separating the combustion and dilution zones. The air inlet boundary conditions were established by utilising the specifications and compressor maps of the Garrett GT25 turbocharger in the simulation. The simulation employed the standard k-ε model of viscous model and energy equation to establish an optimal maximum airflow rate of 0.15 kg/s at a pressure of 1.4 bar, resulting in a compressor efficiency of approximately 70%. Three different fuels, diesel-air, wood-volatiles-air, and coal-hv-volatile, were used to determine the MGT's optimal performance. Successful investigation of this study opts to significant contribution to understand the MGT performance thus, give the awareness to choose as one of the alternative power generations which can be used in the future.

Automated CAD-to-BIM generation of restroom sanitary plumbing system

Abstract Mechanical, electrical, and plumbing (MEP) system experts often have difficulties in converting their designs, in computer-aided design (CAD), into building information models (BIMs) owing to excessive repetitive work, lack of BIM skilled workers, frequent BIM recreations, etc. Therefore, this study aimed to formalize the CAD-to-BIM process of MEP systems, focusing on sanitary plumbing system, including soil, drain system, hot water supply, and cold water supply system. Each system’s process is composed of a combination of the following five common modules: pipeline processing module, pipe connection module, initial level setting module, addition riser nipple module, and clash resolution module. Consequently, a prototype developed based on the formalized process produced a sanitary plumbing BIM model that is identical to the CAD drawings and has no clashes. This study contributes to the MEP BIM theory by identifying considerations for CAD-to-BIM conversion of sanitary plumbing system and formalizing the process reflecting them.

ПОЄДНАННЯ BIM-ТЕХНОЛОГІЇ З СИСТЕМАМИ CAD ДЛЯ РОЗРОБКИ РОБОЧОЇ ДОКУМЕНТАЦІЇ ЗАЛІЗОБЕТОННИХ МОНОЛІТНИХ КОНСТРУКЦІЙ

Explores the potential of combining two technologies - Building Information Modeling (BIM) and Computer-Aided Design (CAD) - in the process of designing monolithic structures, analyzing the feasibility of using both technologies and reveals methods for combining them. The process of issuing documentation based on the BIM model and CAD drawings is considered, in particular the formation of formwork plans in Revit, the design of reinforcing drawings in AutoCAD and the division of drawings into working volumes

Creating digital twins from computer drawings and laser scans: a comparison

Building information models offer significant advantages in managing existing buildings and infrastructure. If no such ‘digital twins’ exist, they can be generated from two-dimensional computer-aided design drawings or from laser scanning photogrammetry. This paper starts by describing and comparing the two methods of model generation. It then reports on a study where both methods were used to model a university building complex in Turkey. The results are compared and discussed, highlighting their respective advantages and disadvantages. It is concluded that the ideal solution is a combination of elements of both methods.

A standard electrolyzer test cell design for evaluating catalysts and cell components for anion exchange membrane water electrolysis

Anion exchange membrane water electrolysis technology is an environmentally friendly method for hydrogen production without carbon dioxide emissions. The development of this technology is hindered by the sluggish rates of the hydrogen and oxygen evolution reactions, demanding the rational design of electrocatalysts for these processes. Although numerous hydrogen and oxygen evolution electrocatalysts are reported in the literature, there is currently no standard set of conditions or cell design under which they can be tested; variance in testing conditions and water electrolyzer components from one study to another therefore hampers a full and coherent comparison of novel electrocatalysts for anion exchange membrane water electrolysis. Herein, a standard water electrolyzer test cell was designed and optimized, such that this test cell can be adopted as a universal framework for evaluating novel electrocatalysts (and indeed other cell components) for anion exchange membrane water electrolysis. The performance of this water electrolyzer was evaluated using a commercial Pt/C hydrogen evolution reaction electrocatalyst, with an optimized cell found to deliver current densities of 1.40 A cm–2 and 2.74 A cm–2 at cell voltages of 2.0 V and at 60 °C using Fumasep FAA-3-50 and Sustainion® X37-50 membranes, respectively. Guidance for assembling and operating the water electrolyzer is provided, along with computer-aided design drawings of the electrolyzer and its components to allow others to construct their own identical cells for benchmarking catalysts and other cell components for anion exchange membrane water electrolysis.

Peningkatan Kompetensi SMK dengan Keterampilan Computer Aided Design

Human capitals in the computer field are required in the Industrial Era 4.0. Vocational schools (SMK) are aimed to produce graduates who are ready-to-use to work in industries. However, SMK graduates are one of the major contributors to high unemployment in Indonesia. Teachers with skills in the field of computer technology are scarce. In addition, the facilities and infrastructure are limited in many SMK schools, especially in rural areas. This community service activity was carried out at SMK Muhammadiyah Tirtayasa. The school is located in the northern coastal rural area of Serang Regency. This community service activity provided assistance to Computer Aided Design (CAD) skills by targeting teachers and students. CAD skills can provide skills for vocational graduates who will have careers in industry. The result showed an increase in the skills of participants in the field of 2D/3D CAD drawing. The activity was very fruitful and can be further followed up by both expanding the partner schools or integrating school curriculum which adopts CAD skills with the aim of developing further the CAD knowledge.

Supplementary open dataset for WiFi indoor localization based on received signal strength

Several Wireless Fidelity (WiFi) fingerprint datasets based on Received Signal Strength (RSS) have been shared for indoor localization. However, they can’t meet all the demands of WiFi RSS-based localization. A supplementary open dataset for WiFi indoor localization based on RSS, called as SODIndoorLoc, covering three buildings with multiple floors, is presented in this work. The dataset includes dense and uniformly distributed Reference Points (RPs) with the average distance between two adjacent RPs smaller than 1.2 m. Besides, the locations and channel information of pre-installed Access Points (APs) are summarized in the SODIndoorLoc. In addition, computer-aided design drawings of each floor are provided. The SODIndoorLoc supplies nine training and five testing sheets. Four standard machine learning algorithms and their variants (eight in total) are explored to evaluate positioning accuracy, and the best average positioning accuracy is about 2.3 m. Therefore, the SODIndoorLoc can be treated as a supplement to UJIIndoorLoc with a consistent format. The dataset can be used for clustering, classification, and regression to compare the performance of different indoor positioning applications based on WiFi RSS values, e.g., high-precision positioning, building, floor recognition, fine-grained scene identification, range model simulation, and rapid dataset construction.

Integrated Schematic Design Method for Shear Wall Structures: A Practical Application of Generative Adversarial Networks

The intelligent design method based on generative adversarial networks (GANs) represents an emerging structural design paradigm where design rules are not artificially defined but are directly learned from existing design data. GAN-based methods have exhibited promising potential compared to conventional methods in the schematic design phase of reinforced concrete (RC) shear wall structures. However, for the following reasons, it is challenging to apply GAN-based approaches in the industry and to integrate them into the structural design process. (1) The data form of GAN-based methods is heterogeneous from that of the widely used computer-aided design (CAD) methods, and (2) GAN-based methods have high requirements on the hardware and software environment of the user’s computer. As a result, this study proposes an integrated schematic design method for RC shear wall structures, providing a workable GAN application strategy. Specifically, (1) a preprocessing method of architectural CAD drawings is proposed to connect the GAN with the upstream architectural design; (2) a user-friendly cloud design platform is built to reduce the requirements of the user’s local computer environment; and (3) a heterogeneous data transformation method and a parametric modeling procedure are proposed to automatically establish a structural analysis model based on GAN’s design, facilitating downstream detailed design tasks. The proposed method makes it possible for the entire schematic design phase of RC shear wall structures to be intelligent and automated. A case study reveals that the proposed method has a heterogeneous data transformation accuracy of 97.3% and is capable of generating shear wall layout designs similar to the designs of a competent engineer, with 225 times higher efficiency.

COMPARISON OF ESTIMATION OF REINFORCED CONCRETE STRUCTURE WORKING COSTS BASED ON THE CONCEPT OF COMPUTER-AIDED DESIGN (CAD) AND BUILDING INFORMATION MODELING (BIM)

The cost estimation process is an important aspect of project management. In line with industry 4.0 development, a new concept called building information modeling (BIM) was introduced. However, in the Indonesia construction sector itself, the application of the BIM concept is still not optimal. Many construction actors still using conventional concept using computer aided design (CAD) drawing in estimating project cost. This case study aims to compare the project cost estimation between conventional calculation based on CAD drawing dan calculation with the BIM concept. This case study was designed with quantitative approach where the unit price analysis will refer to The PUPR regulation no 1 of 2022. From the result, it was found that the project cost estimation using conventional calculation based on CAD drawing was Rp.39.249.184.000 meanwhile the project cost estimation based on BIM concept was Rp.38.978.799.000 It can be concluded that the calculation using the BIM concept result a lower cost estimation of RP.270.385.000 or worth 0,69% compared to the cost estimation based on conventional calculation.

Measured, calculated, and egs_brachy I-125 dose distributions in a gold plaque for retinoblastoma treatment.

This study measured and calculated dose distributions around a unique gold plaque for whole-eye radiotherapy (to treat retinoblastoma). The applicator consists of a pericorneal ring attached to the four extraocular muscles and four legs, each loaded with I-125 seeds. They are inserted beneath the conjunctiva in-between each pair of muscles and attached anteriorly to the ring. The applicator was designed in such a way that the dose is directed toward the middle of the eye while sparing surrounding tissues. (I) To compare the measured and calculated data obtained by thermoluminescent dosimeters (TLDs) in a solid-water phantom, a Gafchromic film in a solid-water phantom, the treatment planning systems, and Monte Carlo simulations; (II) to use Monte Carlo simulations for the determination of the dose to the organs at risk by taking the gold shielding and the anisotropy into account. The dose around the applicator was measured using TLDs and Gafchromic EBT2 film in eye-shaped solid-water phantoms. Dose calculations were performed with the TheraPlan Plus and BrachyVision planning system and Monte Carlo simulations with egs_brachy code. A computer-aided design drawing of the applicator was created and used to create the input file for the Monte Carlo simulations. Monte Carlo calculated dose to the optic nerve is 64.8% of the central dose in the eye, whereas the planned dose is 93.7%. The Monte Carlo lens dose varies from 72.0% to 86.1%, whereas the planned dose varies from 73.0% to 84.3%. Monte Carlo-calculated dose to the bony orbit is 11.3%, whereas the planned dose is as high as 54.7% compared to the dose in the center region of the eye. The measured and Monte Carlo-simulated dose distributions matched well, whereas planned dose distributions showed discrepancies in some areas of the eye and outside of the eye due to their ignorance of the shielding effects of the plaque.

Automated structural design of shear wall structures based on modified genetic algorithm and prior knowledge

Shear wall layout requires repetitive revisions and checks by an experienced designer, which is very time-consuming and inefficient. Therefore, an automated and effective approach to structural design of shear wall structures is needed. An automated generation method of structural model from architectural computer-aided design drawings is described, where the semantic segmentation of buildings based on the connected component analysis, graph structure and Procrustes analysis and an effective parametric modeling approach of shear wall structures integrated with prior knowledge are included. Besides, a modified genetic algorithm with greedy strategy is suggested for shear wall layout optimization. The proposed approach is shown to be effective and reliable through two real-world examples, demonstrating the promising future of automated structural design. This study addressed only the earthquake-resistant design of buildings, and other relevant issues such as beam layout optimization, multi-objective optimization, and economic feasibility of construction should also be addressed in the future.

Penguatan kompetensi perancangan mesin melalui pelatihan computer-aided design bagi mahasiswa dan alumni teknik mesin (Strengthening of machine design skills through the computer-aided design training for mechanical engineering students and alumni)

The purpose of this service is to introduce and provide training on the use of Autodesk Inventor software to produce Computer-aided Design (CAD) based technical drawings according to the International Organization for Standardization (ISO). The method is carried out through theory, practice, and discussion, as well as completing machine design tasks independently and in groups. The training materials include working drawings, basic introduction to CAD, two-dimensional (2D) and three-dimensional (3D) drawing modeling, assembly, and presentation of 3D models. Evaluation of activities assessed refers to the readiness to complete the design task and the suitability of the drawings according to ISO standards. Based on the results of the basic level CAD training, there were achievements where participants had completed the technical drawing briefing material and completed the given design task. The design project task given requires mastery in terms of making 3D models from 2D sketch images, making layout drawings, making working drawings, and presenting them in a moving model presentation format. Successful completion of the task indicates that the participants understand and can operate the Autodesk Inventor software. In conclusion, this basic ability can be used as a provision for participants' self-development in the development and mastery of advanced CAD. This activity contributes based on the high interest in participating in training to the end and completing assignments and also has an indirect impact on the preparation of skilled CAD workers in the industry in Aceh.

Designing a 3D Printed Prosthetic to Meet Task-Specific Needs: A Case Study

The purpose of this case study is to explore the ease of utilizing task-specific design in computer-aided, open-source 3D printed design software. Two participants were recruited and assessed using subjective and objective measures to guide the prosthetic designs. Hand measurements were obtained and entered into computer software to create computer-aided design drawings of the digit prosthetics. Field notes were taken throughout this process by the interdisciplinary team and analyzed to address the ease of utilizing this technology. Objective assessments showed that both participants experienced decreased expansion, grip, and prehension strength of their affected hands. Semi-structured interviews with the participants identified several meaningful tasks that a prosthetic device could improve function in and offered valuable guidance in the development of the prosthetic designs. Analysis of the field notes allowed for the identification of six domains within the research questions. Those domains include appropriate assessment utilization, time management, participant responsiveness, clinical reasoning, common language, and available resources. The successful collaboration of occupational therapy (OT) and engineering disciplines resulted in customized 3D printed finger prosthetic designs to meet participants' specified tasks.

Nanolithography toolbox—Simplifying the design complexity of microfluidic chips

Microfluidic devices typically require complex shapes such as funnels, spirals, splitters, channels with different widths, or customized objects of arbitrary complexity with a smooth transition between these elements. Device layouts are generally designed by software developed for the design of integrated circuits or by general computer-aided design drawing tools. Both methods have their limitations, making these tasks time consuming. Here, a script-based, time-effective method to generate the layout of various microfluidic chips with complex geometries is presented. The present work uses the nanolithography toolbox (NT), a platform-independent software package, which employs parameterized fundamental blocks (cells) to create microscale and nanoscale structures. In order to demonstrate the functionality and efficiency of the NT, a few classical microfluidic devices were designed using the NT and then fabricated in glass/silicon using standard microfabrication techniques and in poly(dimethylsiloxane) using soft lithography as well as more complex techniques used for flow-through calorimetry. In addition, the functionality of a few of the fabricated devices was tested. The powerful method proposed allows the creation of microfluidic devices with complex layouts in an easy way, simplifying the design process and improving design efficiency. Thus, it holds great potential for broad applications in microfluidic device design.

ABGS: A System for the Automatic Generation of Building Information Models from Two-Dimensional CAD Drawings

Building Information Modeling (BIM) refers to 3D-based digital modeling of buildings and infrastructure for efficient design, construction, and management. Governments have recognized and encouraged BIM as a primary method for enabling advanced construction technologies. However, BIM is not universally employed in industries, and most designers still use Computer-Aided Design (CAD) drawings, which have been used for several decades. This is because the initial costs for setting up a BIM work environment and the maintenance costs involved in using BIM software are substantially high. With this motivation, we propose a novel software system that automatically generates BIM models from two-dimensional (2D) CAD drawings. This is highly significant because only 2D CAD drawings are available for most of the existing buildings. Notably, such buildings can benefit from the BIM technology using our low-cost conversion system. One of the common problems in existing methods is possible loss of information that may occur during the process of conversion from CAD to BIM because they mainly focus on creating 3D geometric models for BIM by using only floor plans. The proposed method has an advantage of generating BIM that contains property information in addition to the 3D models by analyzing floor plans and other member lists in the input design drawings together. Experimental results show that our method can quickly and accurately generate BIM models from 2D CAD drawings.

The Pavilions at the Alhambra’s Court of the Lions: Graphic Analysis of Muqarnas

This research documents and graphically analyzes the pavilions muqarnas at the Court of the Lions in the Alhambra in Granada, a World Heritage Site. In order to cast some light on the understanding and preservation of these 14th century architectural elements, after a brief report of historical data on catastrophes and restorations, a novel methodology for the case study based on three complementary graphic analyses is presented here: First, there is a review of outstanding images ranging from the 17th to the 20th centuries; subsequently, new CAD (computer-aided design) drawings from pavilions muqarnas testing the theoretic principles from their geometric grouping are accomplished for the first time; and finally, a 3D laser scanner is used to understand the precise present-day state from the point cloud obtained. Comparing drawings allows us to assess the muqarnas relevance while proving, for the first time, that the muqarnas of both pavilions have distinct configurations and different amounts of pieces. Besides, this process reveals geometric deformations existing in the original Nasrid muqarnas compositions, identifying small pieces hitherto unknown, plus additional deformations resulting from adjustments after important threats that both pavilions and their muqarnas overcame for centuries, despite their fragile construction.

Constraints for Improving Information Integrity in Information Conversion From CAD Building Drawings to BIM Model

Computer Aided Design (CAD) systems play an important role in the production of building designs that are used to assist building constructions. Thus, CAD building drawings contain a large amount of building data important for indoor navigation and other related analysis which are often done in BIM (Building Information Modeling). Therefore, the conversion of CAD-based building data to BIM is necessary to make the data in CAD useful for these applications. However, when mapping to the BIM model, there are semantic ambiguities which will have an important impact on the subsequent analysis of the information converted from CAD. This paper addresses these ambiguity problems by first examining the building information represented in CAD drawings and the mapping relationships between the building information in CAD drawings and that in BIM. Once these relationships are established, the semantic ambiguities existed in the mapping were identified and then corresponding constraints were developed to address these ambiguities. The experiment results show that the approach described in this paper can effectively eliminate the semantic ambiguity of the mapping from CAD to BIM and the converted BIM model can effectively support subsequent analysis.

Automatic grading software for 2D CAD files

AbstractUndergraduate computer‐aided design (CAD) courses can have large enrollments, making it difficult for instructors to thoroughly assess each student's assignments and provide individualized feedback. While in some subject areas textbook companies are developing online platforms that adapt problem sets to meet each individual student's needs, there has been apparently little attention to the area of individualized CAD instruction. This paper presents a program that compares students’ two‐dimensional CAD drawings to a solution, computes the number of missing or erroneous features in each student's drawing, and generates a visual comparison of each student's drawing with the solution. The system is implemented both as an offline version for batch processing and an online version for immediate student feedback on assignments. While the system lacks the “smartness” of a human grader, the offline version substantially reduces time spent grading exams and improves grading accuracy and consistency, and the online version encourages students to focus on important details of drawing and provides immediate online feedback for students as they complete assignments, as well as providing after‐the‐fact feedback on exams.

Manufacturing of Metal Frameworks for Full-Arch Dental Restoration on Implants: A Comparison between Milling and a Novel Hybrid Technology.

To determine the trueness and precision of frameworks manufactured with a selective laser melting/milling hybrid technique (SLM/m) and conventional milling by comparing the implant-platform/framework interface with those of the original computer-aided design (CAD). Using a virtual 6-implant-supported full-arch framework CAD drawing, 27 titanium replicas were manufactured by 3 independent manufacturing centers (n = 9/center) using a hybrid SLM/m technology (labs 1 and 2) or the conventional milling technique (lab 3). Using an opto-mechanical coordinate measuring machine, the frameworks' misfit distribution and patterns were analyzed, and the position error between paired platform positions within each framework was evaluated to calculate the misfit tendency for each group. A multilevel analysis using a mixed-effects model was conducted (α = 0.05). The trueness was evaluated as the dimensional difference from the original, while the precision as the dimensional difference from a repeated scan. The 3 dimensional misfits differed significantly among the 3 groups, with the milled group exhibiting the least accurate outcome (p = 0.005). The mean 3D positioning errors ranged from 8 to 16 µm and from 9 to 22 µm for the SLM/m technique (labs 1 and 2, respectively), and from 20 to 35 µm for conventional milling (lab 3). Regarding the misfit distribution pattern, the misfit increased with the distance between paired platform positions in all groups. All groups had 3D misfits well within the error limits reported in the literature. The 3D misfits of new hybrid (SLM/milling) and conventional (milling) procedures differed significantly among them, with the milling technique the less accurate and precise. The largest errors in all groups were found between the most distant implants, resulting in a correlation between the framework span and the inaccuracies.

An Automated Approach to Building and Simulating Dynamic District Heating Networks

In Nordic countries, district heating accounts for a large share of the consumers’ heat demand. In Sweden, roughly 50% of the total heat demand is attributed to district heating. Which, over the past few years, is equivalent to around 50 TWh, and imposes a difficult balance between supply and demand for the suppliers of district heating. For large networks the propagation of heat from supplier to end-user can vary several hours. Further complexities of large networks, which can consist of multiple overlapping rings, is that during transient conditions the flow can actually change direction. A dynamic modeling library has been developed in Modelica using OpenModelica for district heating networks. Methods for modeling, handling data, simulating and the visualization of results has been developed using Matlab. The model has been validated using data from Mälarenergi AB, a local provider of district heating in Västerås, Sweden. The model provides to an acceptable degree in predicting the heat propagation and temperature distribution in a localized case study. Adding a higher level of robustness, the model has the capacity to handle bi-directional and reversing flows in complex ring structures. Through this work, the combination of OpenModelica and Matlab, a framework for automating the building and simulation of district heating networks is obtainable. The implications of automating network modeling from computer-aided design drawings allows for a quick robust overview of how the network is working and how prospective additions to the network could impact the end-users. Furthermore, incorporating visual aspects for heat propagation in a network contributes to a higher understanding of complex network structures.