Structural Design Method Research Articles

Design Method of Gyroid Lattice Structure Based on the Load Paths Direction and Capacity

The Design of lattice structures with triply periodic minimal surface (TPMS) can improve the specific stiffness, strength, heat dissipation, and energy absorption functions of their physical structures. The load-transferred law in the structure can serve as a crucial basis for the design, including the distribution and anisotropy of the unit cells. In this paper, a design method based on load paths is proposed and a series of Gyroid lattice structures with variable density cells, variable direction cells, and combination of variable density and direction cells, are designed with better mechanical properties. The load paths within a given structure are extracted to explicitly provide the load-transferred law. The capacity of the load paths is then proposed to guide the distribution of the cells, and a mapping relationship with the parameters controlling the porosity is established. The lattice structures with variable density cells are designed. Afterwards, the pointing stress vectors of the load paths is defined as the main load-transferred direction in the local region to guide the direction of the cells. Based on the anisotropic behavior of the Gyroid cells, the direction setting principles are formulated, and the lattice structures with variable direction cells are designed. Furthermore, a model generation method is proposed, and the Gyroid lattice structures that combine variable density and direction cells are implemented. Two models are applied to validate the proposed method, including a two-dimensional three-point bending beam and a three-dimensional supporting beam. The obtained results show that for the same porosity, both the variable density and variable direction designs of Gyroid cells allow to improve the mechanical properties. The variable density design outperforms the variable direction design. In addition, the Gyroid lattice structures combining variable density and direction cells have significantly higher performance, which indicates that the proposed design method can more effectively increase the load-bearing performance.

Automated optimisation design of barge structures using integrated knowledge-based approaches

ABSTRACT An integrated automatic optimisation simulation system for barge structure design has been developed to enhance efficiency and quality. This system incorporates a knowledge-based geometrical modelling method for barge structure design, allowing for the automatic construction of computational models of barge sections through direct transfer of geometric models. Furthermore, a barge structure optimisation simulation system integrated with direct calculation has been established. The effectiveness of this approach is demonstrated through the successful application of structural optimisation to a 65 m barge section, resulting in higher quality design solutions. This research offers an efficient and effective method for achieving high-quality design solutions in the field of barge structure design.

Design method for the structure of a gravitational wave detection telescope with low TTL noise

As a critical payload of the gravitational wave detection interferometry system, the tilt-to-length (TTL) noise has a significant influence on the detection accuracy of the interferometry system. The non-geometric TTL (NG-TTL) noise, which is the main component of the TTL noise within the telescope, is closely related to the sensitive aberrations of the system’s small pupil. Due to the different environments of the earth and space, structural deformations of the telescope can cause significantly unfavorable changes in the sensitive aberrations at the small pupil. And its negative influence must be considered carefully during the whole structural design phase of the gravitational wave telescope. In this paper, the theoretical model of the NG-TTL noise within the telescope based on the Fringe Zernike polynomials has been summarized. An evaluation function of the NG-TTL noise within the telescope was proposed. A desensitization design method for the high-stability structure of the gravitational wave telescope was developed. The results show that under the same disturbances, the NG-TTL noise within the telescope was reduced to 0.1 pm·Hz− 1/2 from 2 pm·Hz− 1/2, taking the primary mirror (PM) as an example.

Numerical analysis of critical support stiffness in ring ribs of a sandwich composite pressure shell

ABSTRACT To study the hydro-static pressure carrying capability of a sandwich composite pressure shell with ring ribs, and explore a structure design method, we obtain an empirical formula of the ring rib segments critical support stiffness, which is defined as Dcr , via finite element simulation and theoretical analysis method. It was shown that, Dcr is of great significance in designing the sandwich composite pressure shell structure. On this basis, the parameters were dimensionless and the empirical formula was obtained by fitting serious independent simulated results. The fitting error of the empirical formula is within 2%. This fitting method has a certain theoretical value for the theoretical research of sandwich composite pressure shell structure. The obtained results are useful for desinging the bearing capacity of novel structure.

Seismic Behavior of Resilient Reinforced Concrete Columns with Ultra-High-Strength Rebars Under Strong Earthquake-Induced Multiple Reversed Cyclic Loading

The frequent occurrence of major earthquakes highlights the structural challenges posed by long-period ground motions (LPGMs). This study investigates the seismic performance and resilience of five reinforced concrete (RC) columns with different high-strength steel bars under LPGM-induced cyclic loading, both experimentally and numerically. The results show that low-bond and debonded high-strength steel bars significantly enhance self-centering capabilities and reduce residual drift, with lateral force reductions of 7.6% for normal cyclic loading and 19.2% for multiple reversed cyclic loading. The concrete damage in the hinge zone of the columns was increased; however, the significant inside damage of the concrete near the steel bars made it easier to restore the columns for the damage accumulation caused by multiple loading. Based on the experiment, a numerical model was developed for the columns, and a simplified model was proposed to predict energy dissipation capacity, providing practical design methods for resilient RC structures that may be attacked by LPGMs.

Automatic travel of a mine hole robot adaptive to changes in hole diameters

Abstract In response to the complex and challenging task of long-distance inspection of small-diameter and variable-diameter mine holes, this paper presents a design for an adaptive small-sized mine hole robot. First, focusing on the environment of small-diameter mine holes, the paper analyzes the robot’s functions and overall structural framework. A two-wheeled wall-pressing robot with good mobility, arranged in a straight line, is designed. Furthermore, an adaptive variable-diameter method is devised, which involves constructing an adaptive variable-diameter model and proposing a control method based on position and force estimators, enabling the robot to perceive external forces. Lastly, to verify the feasibility of the structural design and adaptive variable-diameter method, performance tests and analyses are conducted on the robot’s mobility and adaptive variable-diameter capabilities. Experimental results demonstrate that the robot can move within small-diameter mine holes at any inclination angle, with a maximum horizontal crawling speed of 3.96 m/min. By employing the adaptive variable-diameter method, the robot can smoothly navigate convex platform obstacles and slope obstacles in mine holes with diameters ranging from 70 mm to 100 mm, achieving the function of adaptive variable-diameter within 2 s. Thus, it can meet the requirements of moving inside mine holes under complex conditions such as steep slopes and small and variable diameters.

A structured system design method based on multi-domain gradient transformation

In contemporary product system design, addressing diverse user needs necessitates excellent adaptability to expedite the product development process. This paper adopts the concept of “domain” division within the design process as proposed by axiomatic design theory. It integrates structured methods such as the Design Structure Matrix (DSM) and Quality Function Deployment (QFD). A multi-domain gradient model is introduced to analyze the coupling between elements across domains during the design process. Initially, the correlation matrix between functional requirements and technical systems is constructed based on the QFD model. Subsequently, the DSM is utilized to establish the inter-functional coupling strength matrix based on “adjacent nodes” in a complex network. Additionally, the Multi-Domain Matrix (MDM) is employed to create a transformation matrix of part importance. Utilizing this transformation matrix, the PageRank algorithm evaluates the importance and utilization of parts, illustrating the coupling relationship between factors and the correlation of gradients. This approach aims to achieve shorter development cycles and more efficient design for product systems. Finally, the design of a model for a small, unmanned transporter for hilly orchards serves as a case study to verify the proposed method's effectiveness.

Reliability Analysis of High-Pressure Tunnel System Under Multiple Failure Modes Based on Improved Sparrow Search Algorithm–Kriging–Monte Carlo Simulation Method

It is often difficult for a structural safety design method based on deterministic analysis to fully and reasonably reflect the randomness of mechanical parameters, while the traditional reliability analysis method has a large calculation cost and low accuracy. In this paper, based on the seepage–stress coupling numerical model, the random variables affecting the reliability of the collaborative bearing of surrounding rock and lining structures are successfully identified. Then, the improved sparrow search algorithm (ISSA) is used to optimize the hyper-parameters of the Kriging surrogate model, in order to improve the computational efficiency and accuracy of the reliability analysis model. Finally, the ISSA-Kriging-MCS model is used to quantitatively evaluate the reliability of the surrounding rock-reinforced concrete lining structure under multiple failure modes, and the sensitivity of each random variable is discussed in depth. The results show that the high-pressure tunnel structure has high safety and reliability. The reliability indexes of each failure mode decrease with the increase in the coefficient of variation (COV) of random variables. In addition, the same random variable also exhibits varying degrees of influence in different failure modes.

Optical System Design of a Self-Calibrating Real Entrance Pupil Imaging Spectrometer

Presently, on-orbit calibration methods have several problems, such as low calibration accuracy and broken traceability links, so an urgent need exists to unify traceable and high-precision on-orbit radiometric calibration loads as benchmarks for cross-transfer radiometric calibration. Considering the deficiencies of current on-orbit calibration, this paper proposes adjusting the size of the variable diaphragm at the entrance pupil and the integration time to attain large dynamic attenuation, converting the radiometric calibration into absolute geometric calibration of the attenuation device, and realizing a self-calibrating real entrance pupil imaging spectrometer (SCREPIS) that can be directly used to view the Earth and the Sun and quickly obtain apparent reflectance data. An initial structural design method based on the distance between individual mirrors is proposed according to the instrument design requirements. The design of a real entry pupil image-side telecentricity off-axis three-reflector front optical system with a 7° field of view along the slit direction, a 3.7 systematic F-number, and a 93 mm focal length is finally realized, and the system image plane energy is verified to change proportionally to the variable diaphragm area. Finally, the front system and rear Offner optical system are jointly simulated and optically designed. The system provides instrumental support for cross-calibration and theoretical support and a technical basis for planning space-based radiation references.

Neural Network Methods in the Development of MEMS Sensors.

As a kind of long-term favorable device, the microelectromechanical system (MEMS) sensor has become a powerful dominator in the detection applications of commercial and industrial areas. There have been a series of mature solutions to address the possible issues in device design, optimization, fabrication, and output processing. The recent involvement of neural networks (NNs) has provided a new paradigm for the development of MEMS sensors and greatly accelerated the research cycle of high-performance devices. In this paper, we present an overview of the progress, applications, and prospects of NN methods in the development of MEMS sensors. The superiority of leveraging NN methods in structural design, device fabrication, and output compensation/calibration is reviewed and discussed to illustrate how NNs have reformed the development of MEMS sensors. Relevant issues in the usage of NNs, such as available models, dataset construction, and parameter optimization, are presented. Many application scenarios have demonstrated that NN methods can enhance the speed of predicting device performance, rapidly generate device-on-demand solutions, and establish more accurate calibration and compensation models. Along with the improvement in research efficiency, there are also several critical challenges that need further exploration in this area.

Programmable Intelligent DNA Nanoreactors (iDNRs) for in vivo Tumor Diagnosis and Therapy.

With the rapid advancement of DNA technology, intelligent DNA nanoreactors (iDNRs) have emerged as sophisticated tools that harness the structural versatility and programmability of DNA. Due to their structural and functional programmability, iDNRs play an important and unique role in in vivo tumor diagnosis and therapy. This review provides an overview of the structural design methods for iDNRs based on advanced DNA technology, including enzymatic reaction-mediated and enzyme-free strategies. This review also focuses on how iDNRs achieve intelligence through functional design, as well as the applications of iDNRs for in vivo tumor diagnosis and therapy. In summary, this review summarizes current advances in iDNRs technology, discusses existing challenges, and proposes future directions for expanding their applications, which are expected to provide insights into the development of the field of in vivo tumor diagnostics and targeted therapies.

Application and Practice of Mathematical Optimization Method in Structural Mechanics Design

Application and Practice of Mathematical Optimization Method in Structural Mechanics Design

Structure design and ultimate strength envelope of a modular carbon fiber-reinforced polymer (CFRP) laminate tube box on a 5000 ft deep-sea ultra large unmanned underwater vehicle

Deep-sea tube box is a crucial and basic structural component of various deep-sea equipment such as deep-sea submarine and unmanned underwater vehicles. The deep-sea ultra large unmanned underwater vehicle (ULUUV) is the most representative one of them. Tube boxes are the basic modular members on the ULUUV, which are widely used as the load-bearing hull in torpedo launch, load transportation, pipeline protection and etc. Due to the extremely harsh operation condition, deep-sea tube box simultaneously suffers extremely high lateral water pressure and tremendous axial compression induced by water pressure. Considering the strict requirements for lightweight, high strength, and corrosion resistance of deep-sea tube boxes, carbon fiber-reinforced polymers (CFRP) have become the most potential choice for the construction materials of future deep-sea tube box. Thus, the aim of this paper is to make a structure design of a deep-sea CFRP tube box which can operate at the water depth of 5000 ft. In this paper, a detailed design process of the deep-sea CFRP tube box was introduced, including geometrical configuration, critical buckling load prediction method, FE modeling technique and experimental validation. Corresponding to 5 ply schemes, 495 cases of FE analyses were performed to obtain the ultimate strength envelopes of the CFRP tube box subjected to combined axial compression and external lateral water pressure. Based on the obtained results, the best ply scheme for the deep-sea CFRP tube box was figured out. This paper could provide design method and data references for deep-sea CFRP structures which are subjected to combined loads.

Structural design and motion characteristics analysis of dual-mode active swing arm tracked robot

Focusing on the demand for complex terrain traversal capability of mobile robots, this paper presents a mobile and creep dual-mode tracked robot configuration with capability of autonomous extrication, in response to solving the problem of tracked robots trapped due to insufficient obstacle-crossing capability. Based on the geometrical characteristics of parallelogram and its dynamic computation on the ground, a topological configuration of mobile tracked mechanism with the ability of creep is studied. An integrated structural design method of mobile chassis that integrates the swing arm and the tracked mechanism is proposed and a dual-mode active swing arm tracked robot structural model is established. The mobile and creep characteristics of the dual-mode active swing arm tracked robot are revealed through comparative simulations in multiple working conditions; Through the prototype tests in such typical working conditions as climbing, turning and obstacle-crossing, the feasibility of creep for the robot is verified and it is proved that the obstacle-crossing ability can be effectively improved. The research results provide theoretical support for improving the adaptability and possibility of mobile robots in complex terrain.

Optimization of Composite Wheel Fender for Manned Lunar Vehicle

Abstract Weight reduction is the eternal theme of aerospace optimization. In the process of weight reduction, the main ways are material change, structural change, and processing method change. In the process of aerospace structure design, the boundary and load conditions are more complicated, which restricts the development of optimization technology in the aerospace field to some extent. At present, the research object of optimization technology in the aerospace field is mainly the large parts of the aerospace craft, and the structural optimization of small aerospace parts is rarely involved. Therefore, the research of structural optimization design method has important theoretical and engineering significance. A complete optimization design process is proposed, the structural performance of aviation products is simulated by finite element software, and the feasibility of the optimization theory is verified. This article mainly compares several schemes for weight reduction design of composite material wheel fenders in the process of design.

Design analysis and experimental verification of insulation blankets for civil aircraft nacelle and pylon

Abstract The nacelle and pylon structures of civil aircraft, due to their proximity to the engine, are significantly affected by the high-temperature components of the engine. To reduce the impact of high temperatures on the nacelle and pylon structures and their internal systems, insulation blankets are typically arranged on the inner side of the nacelle fan cowl, the inner side of the core cowl, and the bottom area of the pylon to decrease the thermal transfer effect from the high-temperature components of the engine and the hot air inside the core compartment to the nacelle and pylon structure. This paper mainly describes the structural design method and requirements for the nacelle pylon insulation blanket, and through thermal analysis theoretical calculations, the temperature changes on the cold side of the insulation blanket at different hot sides are derived. The results are compared with the insulation test results of the insulation blanket test pieces, further verifying the insulating performance of the blanket. In addition, environmental qualification tests were conducted on the insulation blanket test pieces, and insulation tests were re-performed on the test pieces after environmental testing, demonstrating the reliability of the nacelle and pylon insulation blanket design.

Ultrasonic and conventional fatigue behavior, strain rate sensitivity, and structural design methods for wrought and cold spray Al-6061

Cold spray is an additive manufacturing process that accelerates powder particles to supersonic speeds to create repairs and bulk depositions with fine-grained microstructures, high density, and good mechanical properties. Fatigue property measurement for these novel materials is critical for their use in safety-critical components, which can be accelerated with the use of ultrasonic fatigue testing. In this work, ultrasonic (20 kHz) and conventional (20 Hz) fatigue studies were conducted on as-sprayed bulk Al-6061 and conventional wrought Al-6061-T6. Complementary fatigue studies of surface preparation (surface finish and residual stress) and fatigue specimen geometry (round versus flat), as well as hole-drilling residual stress measurements, were undertaken to minimize the influence of these confounding variables. Cold spray Al-6061 exhibits fatigue frequency sensitivity, whereas the wrought material does not. Tensile testing at varied strain rates indicates that a portion of the fatigue frequency effect can be attributed to strain rate sensitivity. Fractographic studies show that crack initiation occurs from unbonded powder particles at the surface at high stress amplitude, and transitions sub-surface at lower stress amplitude. The results of these studies were used to create frequency-corrective models of S-N data and Kitagawa-Takahashi diagrams that can be used to design for fatigue crack initiation and growth resistance.

Stability analysis of micro-probe landings in complex terrain

Abstract Addressing the problem of landing stability of the micro-probes on the surface of extraterrestrial objects, combined with the geometric properties of the orthotetrahedron, this paper proposes a structural design method of the four-spine microprobe landing bracket that can adapt to the complex terrain and carries out the analysis of the landing stability of the four-spine bracket under the state of three-legged landing and the optimization of the structure for combined terrain of stones and slopes. Referring to the ZMP theory, the harsh working conditions of the four-spine bracket when landing are sorted out and determined. Based on the kinematics theory, the collision mechanism between the four-spine bracket and the ground is analyzed, and a landing model suitable for the micro-probes is established, which provides the basis for determining the landing stability of the micro-probe. Around the collision mechanism and landing model, the dimension optimization of the four-spine bracket is carried out, and the results of Adams dynamics simulation analysis and prototype test show that the landing stability of the four-spine bracket is improved, which verifies the validity of the optimization idea.

Realization of building grade fire resistance in independent fire zone of energy storage system

Abstract Lithium battery energy storage technology is one of the most promising technologies in the field of energy storage. The fire prevention and control of energy storage system usually needs to consider the cooperation of various parts of the energy storage system. The domestic standard requirements for the fire resistance of energy storage system have not been completely established. In this paper, combined with the US standard and related fire resistance experimental standards, the relevant requirements and test methods for the fire insulation performance of battery cabinet of the energy storage system are studied, and a set of structural design methods and test schemes for the 2h fire resistance limit of the energy storage system are formed. The research shows that the fire insulation of the battery cabin has positive significance for reducing the energy consumption of the air conditioning of the energy storage product, improving the battery life, and enhancing the safety performance of the energy storage system. It is of great significance to study the suitable fire resistance limit of energy storage products for improving the land utilization rate of energy storage system and saving the construction cost.

Honeycomb-like Microthermal Traps on a Photothermal Surface for Highly Efficient Solar Evaporation.

Solar evaporation is an ecofriendly and practical method for seawater desalination. The photothermal layer, which absorbs solar energy and converts it to thermal energy, plays a crucial role in enhancing the efficiency of the evaporator. However, structural design methods for photothermal layers are often complex and energy-intensive. This work reports a simple and efficient strategy for fabricating a necklace-like beaded nanofiber self-organized honeycomb-structured photothermal material. The honeycomb-like cavities form numerous microscale thermal traps, achieving thermal localization while maintaining high energy utilization efficiency, which not only increases light absorption but also facilitates the diffusion and escape of steam. Besides, the hydrophobic honeycomb layer separates the photothermal layer and the interface water, which reduces considerable heat conduction loss and achieves an effective antisalting performance. These functional features endow the evaporator with an evaporation efficiency of 92.9%, and the evaporation rate reaches 2.11 kg m-2 h-1 at 1 sun irradiance, demonstrating its great potential for practical solar-driven seawater desalination under natural sunlight.