Mechanical Structure Design Research Articles

Topology Optimization of the Bracket Structure in the Acquisition, Pointing, and Tracking System Considering Displacement and Key Point Stress Constraints

The lightweight and displacement-stable design of the mechanical support structure within the APTS (Acquisition, Pointing, and Tracking System) is crucial for enhancing the payload capacity of remote sensing, satellite communication, and laser systems, while still meeting specified functional requirements. This paper adopts the Solid Isotropic Material with Penalization (SIMP) method to investigate the structural topology optimization of the L-shaped bracket in the APTS, aiming to minimize structural compliance while using volume, key point displacement, and maximum stress as constraints. In the optimization model, differences in the topology of the L-shaped bracket structure are explored to minimize structural compliance, which was performed under volume, key point displacement, and stress constraints, and the results are compared with the initial reinforced structure. The innovative L-shaped bracket structure obtained through topology optimization uses significantly less material than the initial reinforced design, while still meeting the displacement and stress constraints. After smoothing, rounding, and finite element analysis, the displacement and stress performance of the optimized L-shaped bracket structure satisfies the set constraints. The method proposed in this paper offers an innovative solution for the lightweight design of mechanical support structures in APTS, with significant engineering application potential.

Structural topology optimization based on deep learning

In the mechanical design of structures, traditional topology optimization methods involve numerous finite element iterative analyses, leading to a significant expenditure of computational resources. Therefore, the improved multi-scale gradient generative adversarial networks topology optimization technique is proposed. The topology optimization condition parameters are compressed into a low-dimensional latent space feature representation using the encoder, allowing the model to better extract features from these parameters. To speed up model training, the generator and discriminator networks use lightweight residual convolutional blocks. The hybrid attention mechanism extracts prominent region features from the topology optimization structure map. The model training process is guided by a multi-dimensional fusion loss function to enhance the quality of generated model samples. Finally, transferring the parameters of the low-resolution topology optimization model to the high-resolution model enables complete training on a limited amount of high-resolution topology optimization datasets. The experimental data on the low- and high-resolution topology optimization datasets demonstrate that, when compared to alternative methods, this method produces better-quality topology optimization structure maps. Additionally, it can generate high-resolution topology optimization structure maps in minimal time, enabling real-time topology optimization.

Design and analysis of mechanical structure for on-board HTS magnets subjected to high acceleration

Design and analysis of mechanical structure for on-board HTS magnets subjected to high acceleration

Research on Automatic Pipe Cleaning Technology for Natural Gas Medium and Low Pressure Pipelines

Abstract As the number of low-production and low-efficiency wells in Chang Qing gas field increases gradually, and the problems of pipeline liquid accumulation, freezing plugging and leakage due to production with liquid are worsening, in view of the low efficiency of manual analysis of abnormal pipeline status, the difficulty of timely detection of potential problems and the labor intensity of manual blockage clearing operation, we study an automatic pipeline clearing technology applicable to medium- and low-pressure gas pipelines in the gas field, which mainly includes pipeline operation status analysis and early warning system and automatic pipeline clearing device. An analysis and warning algorithm module is proposed to analyze, warn and locate the frozen plugging point based on pipeline pressure, differential pressure and flow parameters in real time. A low and medium pressure balling device is designed to achieve the goals of intelligent control, pressure isolation balling and safe operation through mechanical structure design, automatic control system and safety protection system. The device and system are applied in the well field at the end of 1 and 3# trunk pipelines of Shen Mu Gas Field Station 7, which verifies the feasibility, accuracy and stability of the technology. Based on the joint operation of the pipeline analysis and warning system and the automatic pipeline clearing device, it is able to meet the remote intelligent pipeline clearing operation and pipeline maintenance tasks in the process of gas gathering and transmission in the gas field.

A Miniature PMUT Array for Medical Applications

Abstract Wearable continuous monitoring technology and internal and cerebrovascular imaging are the frontier hot area of current scientific research, which are of great significance to improving human life and health. Ultrasonic imaging can obtain information such as deep tissue structure by transmitting ultrasonic waves into the tissue and detecting echo signals, and ultrasonic imaging technology has the advantages of high imaging depth, high resolution, high safety, fast and convenient, etc. It is one of the important technologies in the medical field such as wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging. But miniaturization and low power consumption are necessary conditions for the success of such medical applications. Therefore, the ultrasonic imaging technology using a miniature ultrasonic probe is one of the most promising imaging technologies for this type of medical application. Aiming at the common technical problems of traditional ultrasonic transducers such as large volume, narrow bandwidth, high power consumption, difficulty in preparing two-dimensional arrays, and difficulty in integrating with ICs. In this paper, the electromechanical-acoustic multi-field coupling mechanism and array structure design technology of MEMS high-performance PMUT ultrasonic transducer elements are first studied, and a CMOS-compatible miniature PMUT high-performance array ultrasonic device suitable for this type of medical application is developed. The simulation results of the transducer are given. The measurement of various physical parameters of the transducer sample and the results of its application in the ultrasonic imaging system show that the miniature PMUT linear array ultrasonic sensor we designed is a kind of high performance ultrasonic array sensors that can be widely used in wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging.

Statistical analysis of adhesive rod-tube joints under tensile stress for structural applications

Adhesive bonding has been replacing traditional joining methods such as welding, bolting, and riveting in the design of mechanical structures in the automotive, aerospace and aeronautic industries. This joining method has several advantages over traditional methods such as ease of manufacture, lower costs, ease of joining different materials, higher fatigue resistance, and high corrosion resistance. Although tubular adhesive joints have varying applications, such as in truss structures and vehicles, machine axles, and piping, different joint configurations exist, such as rod-tube joints (RTJ), which are not conveniently addressed in the literature. This work compares the tensile performance of adhesively bonded RTJ between aluminium alloy components (AW6082-T651), considering the variation of the main geometric parameters: overlap length (LO), tube thickness (tS), rod diameter (d), adhesive fillet angle (f), and type of adhesive. The Taguchi’s method was employed in the elaboration of the applied design of experiments (DoE). To compare the RTJ behaviour, a numerical analysis was carried out through finite element analysis (FEA) and cohesive zone modelling (CZM). Peel (σy) and shear (τxy) stresses in the adhesive layer were initially obtained by applying purely elastic models. CZM modelling made possible to obtain the damage evolution in the adhesive layer, the maximum load (Pm) and dissipated energy (U) at Pm of the adhesive joints. As a result of applying the Taguchi method, the adhesive joint that showed the best overall performance used the adhesive Araldite® AV138, LO = 40 mm, d = 20, and tS = 3 mm.

Weight evaluation of comprehensive evaluation of difficulty in mechanical structure design of toy products based on ANP

Weight evaluation of comprehensive evaluation of difficulty in mechanical structure design of toy products based on ANP

Fault diagnosis and analysis of automobile capacitive touch display false triggering

Abstract Nowadays, automobile handling is mainly concentrated in the central control display. The use of high-definition and large-size capacitive touch displays has become the mainstream trend. Driving information and entertainment information are displayed on it, and the operation of the electronic control function of the car is generally realized by touching the touch panel of the central control display. As the integration of the central control display becomes higher, the fault of the display needs to be paid more attention to. The common faults include display faults and touch faults. The display fault will affect the display of vehicle information, and the driver cannot obtain vehicle status information; the touch fault will affect the car operation and can not carry out human-machine interaction. Therefore, once the central control display fails, it will affect the safety driving of the car. This paper studies the false triggering failure which is a kind of touch fault of the vehicle’s 9-inch capacitive touch display. Firstly, we test the parasitic capacitance of faulty parts and repeat the touch failure. After testing and analyzing, it has been found that the mechanical structure design of the display and the air gap bonding process can change the value of parasitic capacitance which leads to false triggering. This paper proposes solutions to solve this failure which are changing the wideness of glue to avoid glue overflow and strengthening size management to improve the spacing between the touch panel and the TFT display screen. After the implementation of the solutions, the false triggering failure no longer occurs, which proves that the solutions are effective and feasible.

Mechanical Structure Design of Pressure Sensors with Temperature Self-compensation for Invasive Blood Pressure Monitoring

Abstract Invasive blood pressure (IBP) is a fundamental part of basic cardiovascular monitoring. Conventional piezoresistive pressure sensors are limited in usage due to the high cost associated with equipment and intricate fabrication processes. Meanwhile, low-cost strain gauge pressure sensors have poor performance in the gauge factor (GF) and temperature insensitivity. Here, we report a mechanical structure design for diaphragm pressure sensors (DPSs) by introducing a compensation grid to overcome the aforementioned challenges. A simplified model is established to analyze the mechanical deformation and obtain the optimal design parameters of the DPS. By rationally arranging the placement of sensitive grids to eliminate the discrepancy of relative resistance changes within four arms of the Wheatstone full-bridge circuit, the appropriate GF and high temperature insensitivity are simultaneously achieved. The blood pressure sensor with the DPS is then fabricated and characterized experimentally, which demonstrates an appropriate GF (ΔU/U0)/P = 3.56 × 10−5 kPa−1 and low temperature coefficient of voltage (ΔU/U0)/ΔT = 3.4 × 10−7 °C−1. The developed mechanical structure design offers valuable insights for other resistive pressure sensors to improve the GF and temperature insensitivity.

Design and analysis of mechanical mechanism of cold-forming equipment for marine profiles

Abstract For the existing cold bending machine with complex structure, low automation, and poor motion accuracy. A cold-forming machine that can be used for cold-forming processing of ship profiles is designed in this paper. Firstly, the general structure of the equipment is described. Secondly, the key mechanical structures, such as the guiding mechanism, the feeding mechanism, and the cold bending mechanism, are explained. Finally, the finite element models of key components were mechanically analyzed. The results show that the mechanical structure design proposed in this paper not only meets the mechanical design requirements needed for the system but also can effectively prevent the profile from slipping during the feeding process and achieve highly accurate automatic cold bending processing of the profile.

Dual-mode electromagnetic-triboelectric-piezoelectric multifunctional self-charging energy system for efficient capture of kinetic energy

This study presents an innovative dual-mode electromagnetic-triboelectric-piezoelectric multifunctional self-charging energy system (MS-CES) that integrates two different operating modes of electromagnetic generators for contact-separation (CS-EMG) and non-contact (NC-EMG), as well as a triboelectric nanogenerator (TENG) and a piezoelectric nanogenerator (PENG). The system has an energy management circuit that efficiently captures and converts kinetic energy from the environment. We investigate the output performance of each unit of the MS-CES under different vibration frequencies and amplitudes. The units work together through a compact mechanical structure design to achieve high voltage output while shortening charging time based on improved space utilization, thus gaining more efficient energy storage. Polyacrylonitrile (PAN) powder and barium titanate (BTO) composite nanofibre membrane (PAN/BTO) as PENG material further enhances the system's output performance. The system provides a continuous power source for the vibration sensors. It enables human-computer interaction with mobile phones and computers via Bluetooth modules, enabling real-time monitoring and analysis of vibration parameters. Furthermore, we have validated the feasibility of using the MS-CES to power a noninvasive vagus nerve stimulation device, providing new technological means for monitoring and treatment in the medical field.

Compressive Characteristics and Energy Absorption Capacity of Automobile Energy-Absorbing Box with Filled Porous TPMS Structures

In order to meet the higher requirements of energy-absorbing structures in the lightweight automobile design, the mechanical design and impact energy absorption of porous TPMS structures are studied. Eight kinds of porous TPMS structure elements, Gyroid, Diamond, I-WP, Neovius, Primitive, Fischer-Koch S, F-RD, and PMY, are designed based on Matlab, and the porous structure samples composed of eight elements are printed and molded using SLM. The deformation mechanism, mechanical response, and energy absorption characteristics of different porous TPMS structures are investigated. Gyroid and Primitive elements are selected to fill the internal structure of the energy-absorbing automobile boxes. Traditional thin-walled energy-absorbing boxes served as a control group and were subjected to low-speed impact testing. The results show that the peak load of the energy-absorbing box filled with TPMS porous structures is almost equal to the average load under a 4.4 m/s impact, and the SEA of the energy-absorbing box filled with TPMS porous structures is higher than the traditional thin-walled energy-absorbing box. The problems of excessive peak load and inconsistent load fluctuation of traditional thin-walled energy-absorbing structures are effectively solved by porous TPMS structures with the assurance that the lightweight and energy-absorbing requirements are still met.

Analysis of the influence of mechanical element discontinuities on unbalancing

The study of rotor unbalancing is essential for safety and reliability in the design of machinery and other mechanical structures with rotating parts. By understanding the dynamic behavior and effects of unbalanced components, engineers can address this issue and establish a maintenance program to safeguard mechanical systems from excessive vibrations and prevent catastrophic failures, primarily due to fatigue. Balancing in one and two planes is the most common procedure to correct unbalanced masses in rotating parts. In this work, the aim is to advance the understanding of the effects of mass distribution in irregular-section parts and develop a tool to calculate and improve balancing. In certain situations, there are local limitations to corrections, such as adding correction mass due to irregularities and machine element constraints. To validate the proposed solution, a sample of a crankshaft and a camshaft actuation mechanism was used, where unbalancing is a common issue due to the inherent geometric discontinuities in these types of components. The achieved result demonstrated the validity of the application, allowing the balancing of the samples within the levels recommended by the standard.

Research on Mechanical Leg Structure Design and Control System of Lower Limb Exoskeleton Rehabilitation Robot Based on Magnetorheological Variable Stiffness and Damping Actuator

During the walking process of lower limb exoskeleton rehabilitation robots, inevitable collision impacts will occur when the swinging leg lands on the ground. The impact reaction force from the ground will induce vibrations in the entire robot’s body from bottom to top. To address this phenomenon, considering the limitations of traditional active compliance and passive compliance methods, a variable stiffness and damping actuator (VSDA) leg structure using a magnetorheological damper (MRD) is proposed. Firstly, experimental methods are used to obtain the ground reaction force (GRF) exerted on a normal person during walking. Then, a mathematical model of the VSDA leg structure is constructed, and its working principle is analyzed. Based on human mass and dimensions, a 3D model is designed and selected. Finally, a simulation model is built in the MATLAB/Simulink environment using the fuzzy switch damping control strategy to simulate the acceleration and displacement of the human body under sinusoidal and random excitations. The results indicate that under sinusoidal excitation, employing fuzzy switch damping control optimizes human displacement by 72.47% compared to the high stiffness and high damping system, and by 16.95% compared to the switch damping system. Human acceleration is optimized by 52.09% compared to the high stiffness and high damping system, and by 25.2% compared to the switch damping system. Under random excitation, adopting fuzzy switch damping control optimizes human displacement by 59.09% compared to the high stiffness and high damping system, and by 21.74% compared to the switch damping system. Human acceleration is optimized by 78.74% compared to the high stiffness and high damping system, and by 31.66% compared to the switch damping system. This validates the VSDA design structure and control method, demonstrating certain advantages in improving the compliance and stability of lower limb exoskeleton rehabilitation robots.

Mechanical Field Guiding Structure Design Strategy for Meta-Fiber Reinforced Hydrogel Composites by Deep Learning.

Fiber-reinforced hydrogel composites are widely employed in many engineering applications, such as drug release, and flexible electronics, with more flexible mechanical properties than pure hydrogel materials. Comparing to the hydrogel strengthened by continuous fiber, the meta-fiber reinforced hydrogel provides stronger individualized design ability of deformation patterns and tunable stiffness, especially for the elaborate applications in joint, cartilage, and organ. In this paper, a novel structure design strategy based on deep learning algorithm is proposed for hydrogel reinforced by meta-fiber to achieve targeted mechanical properties, such as stress and displacement fields. A solid mechanic model for meta-fiber reinforced hydrogel is first developed to construct the dataset of fiber distribution and the corresponding mechanical properties of the composite. Generative adversarial network (GAN) is then trained to characterize the relationship between stress or displacement field, and meta-fiber distribution. The well-trained GAN is implemented to design meta-fiber reinforced hydrogel composite structure under specific operation conditions. The results show that the deep learning method may efficiently predict the structure of the hydrogel composite with satisfied confidence, and has great potential for applications in drug delivery and flexible electronics.

Mechanical performance and design of aluminium alloy beam string structures

Aluminium alloys are widely used in spatial structures because of their lightweight, high-strength, and favourable corrosion resistance characteristics. However, the low elastic modulus of this material results in reduced structural stability compared to that of other construction materials. Therefore, this study proposes incorporating prestress into aluminium alloy structures to improve their structural performance. In this study, two types of aluminium alloy beam string structures (ABSS) are presented along with their corresponding joints. Through static tests conducted on various ABSS joint configurations, this study assesses the in-plane bearing capacity and failure modes of the structures, revealing the mechanism by which prestressing enhances the in-plane performance of aluminium alloy beams. Specifically, this study investigates the influence mechanisms of various factors, such as the rise-span ratio, sag-span ratio, and initial cable force, on the in-plane bearing performance of an ABSS through numerical simulations. Finally, a method calculating the ultimate bearing capacity of aluminium alloy beam string structures is derived by employing the Ritz method, accompanied by design recommendations. The results demonstrate that introducing a prestress can significantly increase the load-bearing capacity by 5–6 times, and the flange-connected joint is determined as more suitable for being implemented in ABSS.

Research on Miniaturization Design of Floor-standing Pole Electric Slewing Mechanism

This study is dedicated to investigating the downsizing design and ensuring the structural robustness of pole-mounted slewing mechanisms, aligning with the dynamic requirements of the power industry. The research encompasses critical facets, including the intricacies of mechanical structure design, meticulous motor selection, and a thorough finite element analysis. The outcomes reveal a noteworthy safety factor of 2.08, surpassing the standard requirement of ≥ 2, albeit without factoring in stress concentration. This study underscores the paramount importance of downsizing design in meeting the evolving demands of the modern power industry. It offers invaluable insights into the structural integrity and stability of the mechanism, thereby ensuring its reliability and safety in practical applications. The implications of these findings are poised to catalyse significant technological advancements in the realm of pole-mounted electric slewing mechanisms.

Design and Research on the Mechanical Structure of a Heavy-Duty Hexapod Robot with Bouncing Characteristics

Based on the lunar exploration project, a mechanical structure design scheme for a heavy-duty hexapod robot movement system with bounce characteristics was proposed. The materials used were determined by the robot's working environment and performance standards. The mechanical structure of a jumping heavy-duty hexapod robot was designed using SolidWorks 3D modeling software. Based on the analysis of the working modes of the root joint, hip joint, knee joint, and jumping energy storage mechanism, the main components of each joint and jumping energy storage mechanism were designed, and a single leg mechanism was obtained. Based on the special soil structure on the lunar surface, the foot end buffer mechanism was designed, and finite element stress analysis was conducted on the key components of the robot model, proving the rationality of the mechanical structure of a heavy-duty hexapod robot with bounce characteristics.

Tri-layer gradient structured micro/nanofibrous nonwovens for high filtration efficiency and low air resistance

The coexistence of PM2.5 pollution and the ongoing pandemic poses significant risks to human health. Protective masks incorporating high-efficiency particulate air filters offer adequate protection against PM2.5 particles. Micro/nanofibrous nonwovens, including melt-blown and electrospun nonwovens, are essential filter materials. This study focuses on the filtration mechanism and geometric structure design of multi-level structured micro/nanofibrous nonwovens. A comprehensive investigation was conducted on a filter core material composed of polyacrylonitrile, a polystyrene electrospun membrane, a polypropylene (PP) melt-blown membrane, and a supporting outer layer of a PP spun-bonded membrane. The resulting nonwovens exhibited exceptional filtration efficiency of 99.98% for PM0.3 particles, with a low pressure drop of 60 Pa at 32 L/min inlet air velocity. Filtration efficiencies of 99.99% and 100% were achieved for PM1.0 and PM2.5 particles, respectively. These characteristics make the designed composite nonwovens a very promising filter material for masks. The study contributes to understanding filtration mechanisms and developing advanced high-efficiency filter materials, enhancing protection against airborne pollutants.

Tunable Ultralow-Frequency Bandgaps Based on Locally Resonant Plate with Quasi-Zero-Stiffness Resonators

In order to suppress the transverse vibration of a plate, a quasi-zero-stiffness (QZS) resonator with tunable ultralow frequency bandgaps was introduced and analyzed. The resonator was designed by introducing the quasi-zero-stiffness systems into mass-in-mass resonators. The plane wave expansion method was employed to derive the bandgap characteristics of the locally resonant (LR) plate with QZS resonators, and corresponding simulations were carried out by finite element method (FEM). The results show that an LR plate with a QZS resonator can provide two bandgaps, and the ranges of the bandgaps agree well with the vibration attenuation bands calculated by FEM. Owing to the introduction of the QZS system, the bandgaps can be easily transferred to a lower frequency or even an ultralow frequency. The damping of the QZS resonators can effectively broaden the vibration attenuation bands. In addition, the differentiated design of the bandgap frequencies can be realized to obtain broadband low-frequency transverse wave suppression performance. Finally, a mechanical structure design scheme was proposed in order to achieve flexible adjustment of the bandgap frequency, which significantly increases the engineering applicability of QZS resonators.