Design Calculations Research Articles

Design and Fabrication of Low-Cost Portable Electric Scooters for Last Mile Connectivity

In metropolitan cities every day, thousands of people commute from one place to another using uncomfortable and polluting means of transport. Literature survey shows there are many varieties of E-scooters available in the market that are either bulky, nonmodular or expensive. Hence the objective is to fabricate a low-cost portable E-scooter that overcomes problems like pollution, range, portability and maneuverability. To fulfil these objectives, project work is initially undertaken with Fine Element Analysis (FEA) of Frame design to withstand all loading conditions. To reduce the cost of fabrication, the design for strength concept is incorporated with the assistance of machine design, vehicle dynamics and electric power train calculations. The present model is 1.27m in height and 0.657m in width considering the anthropometric profile for comfort requirements. The final model consists of many parts mainly, the Direct Current (DC) motor, controller unit, Li-ion battery pack and others. After the fabrication and electric work, the model is tested for manoeuvrability, stability and other ergonomic requirements. It is observed that models can sustain a 120Kg load for a 9km range on fully charged battery condition. Finally, the project satisfies 90% of the design calculations which include, braking distance, acceleration, top speed and gross weight. It is concluded that using design for strength concept, FEA and ergonomic consideration, it is quite possible to fabricate an E-scooter at 50% total cost of the market price.

Stress Concentration Factors of CHS-to-CFRHS Y-Joints Under Axial Tension Loading

A CHS-to-CFRHS Y-joint that consists of a circular hollow section (CHS) brace and a concrete-filled rectangular hollow section (CFRHS) chord by welding has a simple and smooth weld profile that saves time and cost for the fabrication of CHS-to-CFRHS Y-joints and leads to a superior fatigue performance, compared with other welded tubular joints. This investigation presented an analysis of the stress concentration factors (SCFs) of CHS-to-CFRHS Y-joints subjected to axial tension loading of the brace. First, a finite element (FE) modelling method, which was validated with the experimental results cited in the reference, was utilised to establish the FE models of CHS-to-CFRHS Y-joints. Then, a parametric analysis was conducted to investigate the influences of the significant non-dimensional geometric parameters on the SCFs of CHS-to-CFRHS Y-joints. It is found that the intersection angle of the brace and chord has an important influence on the magnitudes of the SCF values. An increase in the intersection angle of the brace and chord will increase the values of the SCFs at the 60° location and saddle. The values of the SCFs at the 60° location and saddle reach the maximum value when the intersection angle of the brace and chord reaches 90°. Furthermore, on the basis of the large database of the SCF results, empirical design equations were established to calculate the SCFs at the crown toe, 60° location and saddle via multiple regression analysis. A safety factor was applied to the empirical design equations to ensure safe and reliable results of SCF calculations for the fatigue design of CHS-to-CFRHS Y-joints in a composite truss structure. Ultimately, a comparative analysis of SCFs was conducted with the FE models of welded tubular joints with rectangular hollow section (RHS) chords and CFRHS chords. The results reveal that infilling concrete in the chord leads to a reduction in SCFs along the weld profile of more than 11% on average, and the peak SCF decreases by more than 15%.

Photoinduced Difluoromethylation Cyclization to Generate Medium-Sized Difluoro-benzo[b]azepines.

Compared with the energetically favorable 5- or 6-membered fluoro-functionalized heterocycles, the construction of medium-sized fluoro-heterocycles is relatively under-researched because of their inherently unfavorable enthalpic and entropic nature. Based on rational design and DFT calculations, a novel photocatalytic difluoromethyl radical-initiated intramolecular 7-endo-trig cyclization was realized, thus affording a sustainable route for the synthesis of challenging fluoro-functionalized medium-sized N-heterocycles. Depending on atomic dipole moment corrected Hirshfeld population (ADCH) charge calculations, the chemoselective 6-exo-trig radical cyclizations were further replenished. Large-scale synthesis and derivatization demonstrated the wide utility of this method.

Design and Shear Bearing Capacity Calculation of All-Welded Irregular Joints in Steel Traditional Chinese Buildings

Design and Shear Bearing Capacity Calculation of All-Welded Irregular Joints in Steel Traditional Chinese Buildings

Investigation of 15-7.5cm Wavelength Single Patch Micro strip Antenna.

In the world today, the relevance of antennas is crucial as they are utilized in various sectors. Thus, this paper focuses on the design and analysis by simulation of a rectangular microstrip patch antenna at a wavelength of 15-7.5cm. The software used for analysis by simulation is known as CST Microwave studio. Furthermore, design calculations were performed and the parameters obtained were used for the simulation. The results obtained revealed that the size of the designed antenna can operate within 2.3256GHz and 2.3923GHz with a maximum return loss of - 36.46dB at 2.3582GHz. The value of the voltage standing wave ratio obtained after the simulation was 1.029 at a resonant frequency of 2.358GHz, which is within the accepted range for communication systems operating in the S-band. The radiation pattern of the antenna was also investigated which revealed the directivity of the antenna to be 6.750dB, with a gain of 1.28dB at a frequency of 2.4GHz

Perancangan Mesin Pemotong Singkong Dadu 562 Kg/Jam Menggunakan Pisau Pemotong Baja Karbon 1066

The cassava dice cutting machine is used to speed up the process of cutting dice forms for Kerupuk Ganepo, which are traditionally made with a knife in Ganepo, Payakumbuh. The stages in designing this cassava dicing machine include ideas, literature studies, data collection, design calculations, and model design until the finished machine is ready for use and reporting. This cassava dice cutting machine uses 1066 carbon steel, has machine dimensions of 520 mm x 300 mm x 600 mm with a production capacity of 562 Kg/hour, 1400 rpm rotation using a 0.5 HP motor as the driving force. This motor's rotation will be transmitted through two pulleys utilizing type A belts. The operating concept is to cut cassava using a modified knife that functions as both a cutter and a suppressor, allowing it to enter the dice knife underneath.

Novel 3-benzylbenzo[d]thiazol-2(3H)-iminium salts as potent DNA benzylating agents: design, synthesis, MTT assay, and DFT calculation

New derivatives of 3-benzylbenzo[d]thiazol-2(3H)-iminium salt were developed, synthesized, and assessed for their cytotoxic effects on the MCF-7 cell line. Among them, two molecules, identified as 3g and 3i, demonstrated notable cytotoxic activity with IC50 values of 41.76 and 58.34 µmol/L respectively, compared to the reference drug Cis-platin, which has an IC50 of 22.36 ± 2.98 µmol/L. Subsequent DNA interaction docking studies were conducted with these compounds. The docking data revealed that both 3g and 3i effectively bind within the minor groove of DNA, showing a preference for interaction with AT-rich sequences over CG-rich sequences. These findings suggest that 3g and 3i are effective DNA-binding agents. Further analysis using Density Functional Theory (DFT) was performed to explore the potential of DNA benzylation by compound 3g. The DFT studies suggested that the benzylation of guanine bases by 3g could occur at room temperature. Nonetheless, further experimental investigations are necessary to validate this hypothesis. The DFT studies suggested that the benzylation of guanine bases by 3g could occur at room temperature. Nonetheless, further experimental investigations are necessary to validate this hypothesis.

IoT-Based LPG Level Sensor for Domestic Stationary Tanks with Data Sharing to a Filling Plant to Optimize Distribution Routes

This research presents the design and implementation of an Internet of Things (IoT)-based solution to measure the percentage of Liquefied Petroleum Gas (LPG) inside domestic stationary tanks. The IoT-based sensor, in addition to displaying the percentage of the LPG level in the tank to the user through a mobile application (app), has the advantage of simultaneously sharing the acquired data with an LPG filling plant via the Internet. The design process and calculations for the selection of the electronic components of the IoT-based sensor are presented. The methodology for obtaining and calibrating the measurement of the tank filling percentage from the magnetic level measurement system is explained in detail. The operation of the developed software, and the communication protocols used are also explained so that the data can be queried both in the user’s app and on the gas company’s web platform safely. The use of the Clark and Wright savings algorithm is proposed to sufficiently optimize the distribution routes that tank trucks should follow when serving different home refill requests from customers located in different places in a city. The experimental results confirm the functionality and viability of the hardware and software developed. In addition, by having the precise location of the tank, the generation of optimized gas refill routes for thirty customers using the heuristic algorithm and a visualization of them on Google Maps is demonstrated. This can lead to competitive advantages for home gas distribution companies.

Design and socialization of elderly-friendly hydraulic toilets for Elderly Shelter PCA Dau, Malang

The spirit of improving the welfare of the elderly is the concern of Amal Usaha Aisyiyah, an autonomous organization under Muhammadiyah by establishing a Shelter for the Elderly in the Dau area, under the management of the Aisyiyah Dau Branch Leadership. One thing that is a serious problem is the need for infrastructure that supports the ease of movement of the elderly. It is common knowledge that the elderly's movements slow down and their motor skills are greatly reduced due to physical factors and age. This is what causes them to fall easily and get injured. And the majority of falls occur in the bathroom, in addition to wet conditions that can cause slipping, also because the toilet is not suitable, or is not friendly to the elderly. This community service is aimed at creating a special toilet design that provides convenience and safety when used. The method applied is by conducting anthropometric observations, interviews with elderly users and administrators and caregivers, conducting design calculations, fabrication followed by product testing and socialization to users. Finally, this community service succeeded in building an elderly-friendly hydraulic toilet with special specifications and has been given to the Shelter for the Elderly. The handover of the product was carried out simultaneously with testing and socialization. This product is expected to increase comfort for the elderly and reduce the occurrence of accidents involving falls in the bathroom.

Capacity of connections on punched metal plate fasteners made of spruce wood reinforced with perforated plates and screws

In Poland, until 2010, a number of buildings were built with the support structure of roofs in the form of timber trusses connections with punched metal plate fasteners. Standardisation changes, i.e. the introduction of Eurocodes in 2010, resulted in, among other things, increasing the values of recommended climatic loads. Due to the above, in structures built several years ago, the load capacity limit for both timber and fasteners is exceeded. Modernisation of structures with these trusses usually leads to the need to strengthen existing nodes. The issue of strengthening connections with punched metal plate fasteners is poorly recognised in experimental (failure) tests, and thus there are no detailed standard guidelines. The purpose of the experimental tests was to identify the behaviour of tension connections on metal plate fasteners and to evaluate the impact of the additional reinforcement in the form of perforated plates and screws. The analysis of the results obtained from the experimental tests allows us to conclude that the reinforced nodes achieved a much higher ultimate load than the one resulting from the design calculations.

The Structural Design and Analysis of the Multi Nozzle Relay Air-Jet Inserting System by Profile Reed Guiding for 3D Weaving Machine

Introduction: Based on the literature, this article designs a parameterized simulation model of a multi-layer jet weft insertion system by profiles reed guidance for a 3D loom on the PTC Creo9.0 platform, including the main supersonic nozzle, supersonic auxiliary nozzle (relay nozzle), and multi-slot profiles reed components. Method: Based on the existing basic theory, experimental results, and empirical data of turbulent jet, the parameters of the multi-layer jet weft insertion system, as well as the structural parameters and the relative positions of the main, auxiliary nozzle and profile reed components, such as the center distance of each layer's main nozzle, auxiliary nozzle spacing, auxiliary nozzle installation angle, spray direction angle, and spray angle, have been determined preliminarily. Result: Further, the basic flow field parameters, such as the supply pressure of the main and auxiliary nozzles and the shape of multi-layer profile reeds, have been determined optimally on the Virtual Prototype Collaborative Simulation Platform (PTC Creo9.0/ANSYS Workbench/Fluent 2024R1), and the rationality of the structural design also been verified; on the premise of ensuring that the airflow velocity of each layer's profiles groove meets the requirements of weft insertion, the design and simulation calculation is repeatedly modified, and the optimal structural design parameters of the multi-layer weft insertion system and nozzle is finally determined. Conclusion: To explore the feasibility of multi-layer jet weft insertion, the design of threedimensional multi-layer jet weft insertion looms has laid a theoretical foundation, laying a good foundation for the emergence and industrial manufacturing of three-dimensional multi-layer jet weft insertion looms, and providing an important reference for the innovative design of threedimensional multi-layer water jet weft insertion looms.

Modeling and Control of Cable-Driven Exoskeleton for Arm Rehabilitation

Abstract Exoskeleton robotics is a key technology in the field of physical rehabilitation, and the main research direction is to precisely control the exoskeleton structure with improved dexterity. Bowden-cables are uniquely structured for power transmission in lightweight wearable exoskeletons, but precisely controlling the exoskeleton system is challenging when considering their inherent limitations such as friction and hysteresis. This paper proposes a compact wearable exoskeleton with Bowden-cable designed for the purpose of rehabilitating the elbow and forearm. First, we optimize the performance of the Bowden-cable transmission by incorporating redirection pulleys, while a mathematical model is developed to describe the Bowden-cable and pulley system (BCPS). Afterwards, guided by the principle of ergonomic concept, the mechanism design and size calculation of the exoskeleton are conducted. Moreover, an optimized sliding mode control strategy was implemented to control the exoskeleton, and the efficacy of the designed controller was assessed through trajectory tracking experiments simulating “eating” movements. Finally, the experimental results demonstrate that the root mean square errors (RMSEs) for elbow and forearm angle tracking are 0.84 deg and 1.13 deg, respectively, indicating that the designed exoskeleton is suitable for arm rehabilitation training.

Confined compressive stress–strain model for rectangular geopolymer reinforced concrete members

AbstractIn response to the urgent global challenge of mitigating climate change, sustainable materials have become a focal point across industries, including construction. The construction sector, recognizing its significant contribution to carbon dioxide emissions, has embarked on a relentless pursuit of eco‐friendly practices. Efforts to explore alternatives to cement, notorious for its substantial carbon footprint, have attracted considerable attention. Within this context, the present study delves into an in‐depth analysis of the stress–strain properties exhibited by geopolymer concrete (GC) column members. The primary objective is to develop a comprehensive material model of geopolymer concrete to estimate the flexural capacities of column members. To this end, inspired by the confinement model by Kent and Park, a stress–strain model incorporating the effect of confinement is proposed to accurately estimate the moment capacity of GC columns. The performance of the proposed formulation is checked using 41 different test results obtained from previous research on GC columns. Evaluations on the moment capacity estimations of the proposed model show that the results are promising in reflecting the behavior of geopolymer columns. In addition, moment–curvature curves from six recent experiments are also compared with the moment–curvature curve estimations using the proposed stress–strain model. Results show very close estimations, proving the ability of the model to be a good candidate for the performance‐based design calculations. Besides, the performance of the existing formulations from four prominent international codes (ACI318, BS8110‐97, TS500, and AASHTO) are compared with the proposed model. Notably, the flexural capacity calculated using the code formulations exhibited significant deviations from the experimental results. In contrast, the proposed model demonstrates a strong correlation with the experimental data, substantiating its effectiveness in accurately predicting the flexural capacities of GC columns.

Analysis of Stress and Strain in Sandwich Structures Using an Equivalent Finite Element Model

The study aims to build an equivalent 2D model as an alternative to the 3D model of sandwich panel structures. This model enables for reducing model building time and calculation time in the design calculation of this sandwich structure. The research object in this study is corrugated core cardboard. First, the isotropic plasticity equivalent (IPE) model for the paper material is implemented in the Abaqus software, using the VUMAT user subroutine. Subsequently, the homogenization method is proposed as an equivalent elastic-plastic finite element model. This model is implemented in Abaqus using the UGENS subroutine. Finally, numerical simulations of different load cases between the 3D model and the equivalent 2D model are performed to confirm the accuracy of the proposed model. The comparison results indicate that the equivalent model ensures exceptional accuracy compared to the 3D model but significantly reduces model building time and CPU time.

Design of a two-seater seaplane wing spar structure with composite materials

A two-seater, mono-wing seaplane was initially developed for survey and rescue operations, with an empty weight of 470 kg and a maximum takeoff weight of 650 kg. Fiber-reinforced composite materials, consisting of fiber reinforcement and thermosetting polymer, were used in this airframe to reduce weight because the structural properties can be customized by adjusting the orientation of the fiber fabric layup and removing redundant material, which is impossible with metal. This paper presents a comprehensive overview of the design process for the aircraft's primary I-beam wing spar, employing composite material. Before conducting design calculations, it is critical to consider the variability of characteristics of composite materials caused by fabrication conditions such as temperature, humidity, and defects. As a result, it is imperative to conduct thorough testing of carbon fiber-reinforced composites following many different testing requirements. The coupon tests capture critical characteristics such as strength, stiffness, and Poisson's ratio across several orientations. The wing spar I-beam structure was subsequently developed with three primary considerations: stiffness (maximum deflection), strength, and stability (structural buckling). Following preliminary sizing of the I-beam wing spar, a simple initial layup was recommended, with primary loading in each component. The initial design was then subjected to a more detailed calculation using classical lamination theory, which took into account distributed load along the wing, spar taper, ply-drops along the span, and composite layup guidelines in order to reduce structural weight while ensuring the main spar's ability to withstand operational loads effectively. The calculating results show that the spar with an optimized composite design has a lighter weight than the original design by around 43%, while it can withstand the same loads with no analytical failure.

Design Calculation and Shaping of the Hydro-Steam Turbine Flow Path with Helical Nozzles

Design Calculation and Shaping of the Hydro-Steam Turbine Flow Path with Helical Nozzles

Compositing effects for high thermoelectric properties of n-type Bi2S3 via doping C60 nanoparticles

Bi2S3 is one of the most inexpensive and eco-friendly thermoelectric materials in the medium temperature region. In this work, functionalized fullerene (C60) was successfully doped into Bi2S3 to optimize its thermoelectric properties by a simple hydrothermal method. Guided by first-principles calculations for compositional design, electron band structure of Bi2S3/C60 nanocomposites is reduced. Additionally, the high modulus elasticity of C60 further increases phonon scattering in Bi2S3. Due to composite effects synergistically optimized the transports of electron and phonon by C60 nanoparticles in Bi2S3-based materials, the electrical and thermal conductivity of Bi2S3-based nanocomposites are optimized and decreased to varying degrees, respectively. The highest power factor (PF) of Bi2S3/C60 nanocomposites is up to 181μW·m-1·K-2, and the lowest thermal conductivity is 0.17W m-1·K-2. Ultimately, the ZT value of Bi2S3/C60 (10ml) nanocomposites reached 0.38, nearly a threefold improvement over the pure Bi2S3, which further expands the application range of Bi2S3-based thermoelectric materials.

Fretting Dynamic Contact Analysis of Planetary Gear-Bearing Interference Fit Surface Considering Non-Uniform Interference

Abstract The planetary gear-bearing interference fit surface is prone to fretting slip under alternating torque, which can lead to fretting wear and fatigue failure. However, the current studies often ignore the influence of non-uniform interference on the stress and strain of the fit surface. In this paper, the force analysis of the planetary gear-bearing interference fit surface is carried out based on thick cylinders theory and planetary gear dynamics, and the fretting slip mechanism is explained in detail. Based on the assumption of plane stress, the equation for interference distribution in the circumferential direction of the fit surface is derived. On this basis, a three-dimensional fretting contact model considering non-uniform interference is established and solved by the conjugate gradient method (CGM). The results show that under the action of alternating torque, the fit surface interference is non-uniformly distributed in the circumferential direction, which shows a trend of increasing first and then decreasing. The fretting slip distance decreases first and then increases in the circumferential direction, but the fretting slip curve considering non-uniform interference shows a slip distance of nil in the range where the interference value exceeds the initial value. The model in this paper is more in line with the actual situation, and can provide more accurate theoretical calculation for the planetary gear-bearing interference fit design.

Electrical Tortuosities of Porous Structures Based on Triply Periodic Minimal Surfaces and Honeycombs for Power-to-Heat Systems

Power-to-heat (P2H) systems offer an efficient solution for decarbonization by facilitating the integration of renewable energy into the industrial, heating, and transport sectors. Its key requirements include high thermal efficiency and an appropriate electrical resistivity to meet application-specific electrical needs. When designing P2H systems, materials and electrical boundary conditions are often limited by application-specific requirements, whereas geometric structures offer high degrees of freedom. While thermal design calculations are often straightforward due to a variety of available Nusselt and pressure loss correlations, simplified design pathways, particularly for porous structures, are lacking in electrical design. Given the wide range of geometric degrees of freedom for porous structures and the fact that detailed modeling involves substantial computational effort, this work employed electrical tortuosity to capture and correlate the geometry-dependent impacts on the effective electrical resistance in a compact way. Honeycomb and triply periodic minimal surface (TPMS)-based structures were selected for this purpose, as they are characterized by high specific surfaces, allowing for high total heat transfer coefficients. The results show that the effective electrical resistance of both TPMS and honeycomb structures can be adjusted by the geometric structure. It was found that the electrical tortuosities of the investigated TPMS structures are nearly identical, while honeycomb structures show slightly higher values. Furthermore, the electrical tortuosity is mainly a function of the void fraction and does not change with the specific surface when the void fraction is kept constant. Finally, correlations for electrical tortuosity depending on geometric parameters with a mean error below 5% are derived for the first time, thereby providing a basis for simplified and computationally efficient electrical design calculations for P2H systems.

Ultrahigh-resolution broadband spectrometer based on grating-beamsplitter interferometer

An ultrahigh-resolution broadband spectrometer based on a grating-beamsplitter interferometer is presented, in which a transmission grating serves not only as a beamsplitter for the interferometer but also as a dispersive element to divide a wide spectral band into multiple narrow spectral bands. The distinctive design reduces the number of optical components of the instrument and simplifies the structure of the instrument. For one scan period, this spectrometer generates multiple interferograms simultaneously, each interferogram covering a separate wavelength range is received by a separate pixel of the linear detector, and the sum of the spectra recovered from all interferograms constitutes a continuous broadband spectrum. The relevant formulas and preliminary design calculation are provided. The simulation is shown by two examples within the spectral range from 300 nm to 500 nm and 900 nm to 1600 nm. This spectrometer will be suitable for ultrahigh-resolution broadband spectral measurements.