Structural Design Process Research Articles

Shape/properties collaborative intelligent manufacturing of artificial bone scaffold: structural design and additive manufacturing process.

Artificial bone graft stands out for avoiding limited source of autograft as well as susceptibility to infection of allograft, which makes it the current research hotspot in the field of bone defect repair. However, traditional design and manufacturing method cannot fabricate bone scaffold that well mimics complicate bone-like shape with interconnected porous structure and multiple properties akin to human natural bone. Additive manufacturing, which can achieve implant's tailored external contour and controllable fabrication of internal microporous structure, is able to form almost any shape of designed bone scaffold via the layer-by-layer process. As additive manufacturing is promising in building artificial bone scaffold, only combining excellent structural design with appropriate additive manufacturing process can produce bone scaffold with ideal biological and mechanical properties. In this article, we sum up and analyze state of art design and additive manufacturing methods for bone scaffold to realize shape/properties collaboratuve intelligent manufacturing. Scaffold design can be mainly classified to design based on unit cells and whole structure, while the basic additive manufacturing and 3D bioprinting are the recommended suitable additive manufacturing methods for bone scaffold fabrication. The challenges and future perspectives in additive manufactured bone scaffold are also discussed.&#xD.

Pushing Radiative Cooling Technology to Real Applications.

Radiative cooling is achieved by controlling surface optical behavior toward solar and thermal radiation, offering promising solutions for mitigating global warming, promoting energy saving, and enhancing environmental protection. Despite significant efforts to develop optical surfaces in various forms, five primary challenges remain for practical applications: enhancing optical efficiency, maintaining appearance, managing overcooling, improving durability, and enabling scalable manufacturing. However, a comprehensive review bridging these gaps is currently lacking. This work begins by introducing the optical fundamentals of radiative cooling and its potential applications. It then explores the challenges and discusses advanced solutions through structural design, material selection, and fabrication processes. It aims to provide guidance for future research and industrial development of radiative cooling technology.

Adding friction to Third Medium Contact: A crystal plasticity inspired approach

This paper presents the first method to enable friction in the Third Medium Contact (TMC) method. TMC embeds a solid in a highly compliant medium, which becomes infinitely stiff under ultimate compression, thus allowing forces to be transferred between the solids when the medium between the solids is compressed. This approach is increasingly adopted for integrating internal contact in structural design processes, owing to its continuous, fully implicit characteristics, simplicity, and its stability when applying regularisation to the third medium regions. The lack of friction has previously restricted the use of the TMC method in simulating real-world contact conditions. Here, we address this issue by (1) integrating an anisotropic term into a Neo-Hookean material model to provide shear resistance, and (2) employing a framework inspired by crystal plasticity that includes a yield criterion specifically designed to replicate the effects of Coulomb friction.The effectiveness of the method is demonstrated through two examples: (1) a smooth sliding contact problem and (2) a non-smooth C-shaped structure. Results demonstrate a close agreement with reference solutions obtained by a conventional Lagrange multiplier approach. While the method, for now, requires user-defined slip directions, it represents a significant advancement by enabling the integration of friction into TMC, thereby broadening its applicability to problems involving realistic frictional contact. Future research should focus on restoring the fully implicit nature of TMC in the presence of friction, and on developing automated slip direction definitions to enhance usability and expand the method’s versatility.

Computer Design of the Regulating Working Element of the Channel Cleaning Equipment

Cleaning devices of channel systems used for irrigation of agricultural plants and mechatronic parts regulating their operations were analyzed, the issues of automation of construction design, measurement and management in this field were examined and the purpose of the work was determined. As the goal of the work, the issue of automation of the construction design, technological measurement and management process of the working body for efficient cleaning of small and medium-sized concrete-covered channels, bathtubs from sludge and weeds was set. A complex scheme of information, algorithmic and software support for the automation of the design, technological measurement and control of the mechatronic parts of the working body used for cleaning the channel and bathtub was proposed, and the issues of logical modeling and simulation of the drawing of 2- and 3-dimensional images of the working body were solved. Algorithms were developed using the production modeling method to automate the process of technological measurement, implementation and management, which accurately regulates the operations of the working body of the mechanical device of complex construction. In Solid Edge 2D, 3D software environments, the determination of the geometric shapes of the individual mechanical parts of the channel cleaning unit with a milling cutter, their sizes and types of materials is ensured, and the algorithm was developed using the logical modeling method. For the automation of the structural design process, the information security of the mechanical parts of the application object and the elements of the new design milling cutter device was created for the management of the database of drawings.

Contribution to the numerical modelling analysis of displacements caused by tunnel construction in discontinuous rock masses

This paper presents a comprehensive study of the stability conditions of a rock mass surrounding a tunnel, using numerical modelling analysis of displacements induced by the tunnel construction. The case study focuses on the Boukhadra iron ore mine in Algeria. This research employs empirical equations from literature based on geomechanical classifications to provide the most appropriate geotechnical input data for simulation. In addition to those equations, a novel correlation equation relating the rock mass ratio (RMR) and the rock quality index (Q) was developed. This equation gives a high regression coefficient, revealing a strong correlation (R2) of 0.878. It gives a better estimation of the rock mass characteristics: Young’s moduli (E), Poisson’s ratio (υ), cohesion (C), and friction angle (φ), compared to the existing literature-based correlation equations. The estimated parameters were used to pass from a discontinuous to a continuous equivalent medium, making the numerical modelling easier with the finite element method. Compared with intact rock and direct equations, the numerical simulation results based on the new equation fit well with the in-situ observations and provide a more reliable comprehension of rock mass behaviour. The new equation proposed in this paper provides a substantial evaluation of the rock mass parameters needed in the design process of underground structures once used with respect to their acceptable ranges.

Research on the Fabrication and Parameters of a Flexible Fiber Optic Pressure Sensor with High Sensitivity

In recent years, flexible pressure sensors have garnered significant attention. However, the development of large-area, low-cost, and easily fabricated flexible pressure sensors remains challenging. We designed a flexible fiber optic pressure sensor for contact force detection based on the principle of backward Rayleigh scattering using a single-mode optical fiber as the sensing element and polymer PDMS as the encapsulation material. To enhance the sensor’s sensitivity and stability, we optimized its structural design, parameters, and fabrication process and measured the fiber strain using an optical frequency domain reflectometer (OFDR). The results showed that the sensor achieved a high sensitivity of 6.93247 με/kPa with a PDMS concentration ratio of 10:1, a curing time of 2 h, and a substrate thickness of 5 mm. The sensor demonstrated excellent linearity and repeatability in static performance tests and was successfully used to monitor the plantar pressure distribution in real time. This flexible fiber optic pressure sensor can be developed via a simple fabrication process, has a low cost, and has high sensitivity, highlighting its potential applications in smart wearables and medical diagnostics.

Biomimetic Contact Behavior Inspired Tactile Sensing Array with Programmable Microdomes Pattern by Scalable and Consistent Fabrication.

Flexible sensor arrays have attracted extensive attention in human-computer interaction. However, realizing high-performance sensor units with programmable properties, and expanding them to multi-pixel flexible arrays to maintain high sensing consistency is still struggling. Inspired by the contact behavior of octopus antenna, this paper proposes a programmable multistage dome structure-based flexible sensing array with robust sensing stability and high array consistency. The biomimetic multistage dome structure is pressurized to gradually contact the electrode to achieve high sensitivity and a large pressure range. By adjusting the arrangement of the multistage dome structure, the pressure range and sensitivity can be customized. More importantly, this biomimetic structure can be expanded to a multi-pixel sensor array at the wafer level with high consistency through scalable and high-precision imprinting technologies. In the imprinting process, the conductive layer is conformally embedded into the multistage dome structure to improve the stability (maintain stability over 22000 cycles). In addition, the braced isolation structure is designed to effectively improve the anti-crosstalk performance of the sensor array (crosstalk coefficient: 26.62dB). Benefitting from the programmable structural design and high-precision manufacturing process, the sensor array can be customized and is demonstrated to detect human musculation in medical rehabilitation applications.

A novel sensitivity analysis method for multi-input-multi-output structures considering non-probabilistic correlations

In practical engineering, a multi-input-multi-output (MIMO) structure generally features a significant number of correlated input parameters and output responses. Sensitivity analysis is usually adopted to select key parameters for improving the computational efficiency of structural analysis and design processes. Traditional sensitivity analysis methods based on probabilistic models for MIMO structures may not reliably and efficiently derive the sensitivity indexes of correlated input parameters with limited samples. To solve the above problems, a novel sensitivity analysis method for MIMO structures considering non-probabilistic correlations is proposed to estimate the influence of uncertainties and correlations among the parameters on the responses in a unified framework. Firstly, a multidimensional parallelepiped (MP) model is employed to quantify the uncertainties and non-probabilistic correlations among the parameters. A new non-probabilistic variance propagation equation based on the MP model is then proposed to derive the non-probabilistic variances of output responses. The non-probabilistic independent, correlated, and total sensitivity indexes of each parameter for multi-input-single-output (MISO) structures are defined according to the non-probabilistic variance contribution rates. A dimensional normalization method and a vector projection method are then adopted to extend the non-probabilistic sensitivity indexes of each parameter for MIMO structures with correlations. Two numerical examples and an experimental example are exemplified to verify the proficiency and efficiency of the currently proposed method.

Development of a novel system for measuring femoroacetabular contact forces in hip arthroscopy

Purpose Arthroscopic osteochondroplasty is a minimally invasive procedure that has been used to treat femoroacetabular impingement syndrome, leading to significant improvements in patients’ clinical outcomes and quality of life. However, some studies suggest that inadequate bone resection can substantially alter hip biomechanics. These modifications may generate different contact profiles and higher contact forces, increasing the risk of developing premature joint degeneration. To improve control over bone resection and biomechanical outcomes during arthroscopic osteochondroplasty surgery, this study aims to present a novel system for measuring femoroacetabular contact forces. Design/methodology/approach Following a structured design process for the development of medical devices, the steps required for its production using additive manufacturing with material extrusion and easily accessible sensors are described. The system comprises two main devices, one for measuring femoroacetabular contact forces and the other for quantifying the force applied by the assistant surgeon during lower limb manipulation. The hip device was designed for use within an arthroscopic environment, eliminating the need for additional portals. Findings To evaluate its performance, the system was first tested in a laboratory setup and later under in-service conditions. The 3D printing parameters were tuned to ensure the watertighness of the device and sustain the intraoperative fluid pressures. The final prototype allowed for the controlled measurement of the hip contact forces in real-time. Originality/value Using additive manufacturing and readily available sensors, the present work presents the first device to quantify joint contact forces during arthroscopic surgeries, serving as an additional tool to support the surgeon’s decision-making process regarding bone resection.

A mobile serious game about diabetes self-management: Design and evaluation

Type 2 Diabetes Mellitus (T2DM) is a chronic condition that requires ongoing self-management and education. In recent years, there has been a growing interest in utilizing mobile serious games as a tool for patient education and engagement. This article presents the development of DiaPo, a mobile serious game designed to improve self-management education for patients with T2DM. DiaPo integrates gamification techniques to increase patient engagement and motivation while providing essential information about disease management. The development of DiaPo followed a structured design process, utilizing the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) educational system. This systematic approach allowed for the integration of best practices in educational game design and diabetes care. The development team consisted of experts in medical informatics, game design, and diabetes care, ensuring a multidisciplinary approach to the game's creation. The game's narrative focuses on a T2DM patient who earns positive points for making healthy lifestyle choices and negative points for poor ones. This gamified approach aims to reinforce positive behaviors and provide immediate feedback on negative ones. Interactive animations confirm or deny options selected by the player, further enhancing the learning experience. DiaPo offers a flexible and adaptable platform suitable for diverse audiences, promoting inclusiveness and accessibility in T2DM education. DiaPo represents a novel approach to self-management education for patients with T2DM, utilizing gamification techniques and a multidisciplinary design process to create an engaging and informative mobile serious game. By promoting inclusiveness and accessibility, DiaPo has the potential to empower patients with T2DM to take an active role in their disease management. As the field of mobile serious games continues to evolve, DiaPo stands as a promising tool for improving T2DM education and patient outcomes.

Bending stiffness analysis of regular polyhedron sandwich structures

Abstract As a new type of sandwich structure, regular polyhedron sandwich structure has excellent structure performances such as high bending resistance and energy-absorbing features. However, the current design process of regular polyhedron sandwich structures often ignores the influence of unit-cell parameters on structural bending stiffness. Based on origami geometry, this study analyzes the geometric characteristics of polyhedron unit-cell structures. A simulation model was established to analyze the bending performance of regular polyhedron sandwich structures. The influence of the number of polyhedron surfaces and similarity transformation parameters on bending stiffness was analyzed by finite element software. Through finite simulation analysis, the influence graph of bending performance in the impact of various parameters was obtained. This analysis provides valuable insights for the optimization design of regular polyhedron sandwich structures.

Failure mode maps for glass fibre-reinforced polymer/polyvinyl chloride foam-cored sandwich structures

Purpose This study aims to understand how the facesheet size, orientation and core size influence the analytical failure mechanism mode of glass fibre reinforced polymer (GFRP)/polyvinyl chloride (PVC) sandwich structures subjected to three-point bending. The purpose of this study was to develop failure-mode map of GFRP/PVC sandwich structures. Sandwich structures with different facesheet and core thicknesses were used to develop the failure map. Design/methodology/approach The sandwich structure and facesheet were fabricated using a vacuum-assisted resin infusion method with core sizes of 10, 15 and 20 mm and facesheet thicknesses of 1.5 and 3 mm and were arranged in three different orientations: angle-ply, cross-ply and quasi-isotropic. The key failure modes that occur in sandwich structures were used to predict possible failures in the developed material. Analytical equations were used in MATLAB for each observed failure mode. The probable failure modes, namely, face yielding, core shear and indentation equations, were used to construct the failure maps and were compared with the experimental data. Findings The boundary of the two failure modes shifts with changes in the facesheet and core thicknesses. The theoretical stiffness of sandwich panels was higher than the experimental stiffness. Based on strength-to-weight ratio, specimens E10-4, A15-8 and E20-8 exhibited the best optimum values owing to their shorter distance to the boundary lines. Originality/value In this study, a failure map was used to predict the possible failure modes for different GFRP facesheet orientations and thicknesses and PVC core thickness sandwich structures. Little is known about the prediction of the failure modes of unidirectional GFRP arranged in different orientations and thicknesses and PVC core thicknesses for sandwich structures. Few studies have used failure mode maps with unidirectional GFRP oriented in angle-ply, cross-ply and quasi-isotropic directions as a facesheet for sandwich structures compared to bidirectional mats. This study can serve as a guide for the correct selection of materials during the design process of sandwich structures.

Unraveling Object-Oriented Dynamics in Architectural Form: The Impact of Randomness in Digital Design Processes

The field of Mereology offers an understanding of the object-oriented dynamics between component parts and theirholistic integrations. Within this framework, architectural form creates a rich landscape of possibilities stemmingfrom the complex interactions among various living and non-living elements. In this perspective, each entity operateswithin its own objective reality, contributing to the rich fabric of relationships that shape architectural form. In thisform-centric approach, deliberate design efforts are complemented by the influences of chance events andrandomness in the assembly of elements. The impact of randomness extends to traditional structural designprocesses, but this effect becomes more pronounced in digital computational environments. As we transition intodigital reality, the representation of objects gains independent significance from their physical counterparts. Here,randomness plays a decisive and constructive role in shaping the digital landscape and forming structures. In thiscontext, this study aims to elucidate the essence and consequences of randomness in the formation of architecturalform. Through meticulous examination of specific examples from form-finding studies, the goal is to determine theextent of randomness's influence.

Quadcopter Unmanned Aerial Vehicle Structural Design Using an Integrated Approach of Topology Optimization and Additive Manufacturing

The performance of quadcopter frames, particularly in terms of weight and crash resistance, is significantly influenced by their structural design and manufacturing process. In this work, a methodology is proposed that integrates advanced principles of topology optimization (TO) and additive manufacturing (AM) techniques to optimize the frame structure for improved performance. First, an analysis is conducted to evaluate existing quadcopter frame configurations, identifying areas for improvement. Experimental evaluations of thrust and moment of motors are performed to assess the performance of the enhanced quadcopter frame, with a focus on advancing the design through computer-aided simulations of static structural analysis and impact tests. The TO technique is then employed to determine the optimal distribution of material within the frame, governed by constraints such as weight reduction and mechanical strength. The results demonstrate that the overall performance of a quadcopter frame is significantly improved by the proposed methodology, showcasing advancements in stability, weight reduction, and crashworthiness. The resulting optimized frame design is subsequently manufactured using AM methods, which offer advantages such as design flexibility and the ability to produce complex geometries. The findings of this study contribute to the field of quadcopter design and optimization by highlighting the synergies between TO and AM techniques. An avenue is offered for the development of lightweight and robust quadcopter frames, as the capabilities and performance of quadcopter systems are advanced. The insights gained from this research open up opportunities for further advancements in the design and manufacturing of UAVs.

Optimal design and analysis of a space lightweight mirror with a directionally oriented 2.5D-CVT structure

Reflective mirrors are the key imaging components of space-borne telescopes, which require a high lightweight ratio integrated with excellent optical properties. In this context, a novel, to our knowledge, 2.5D centroidal Voronoi tessellation (CVT) generation methodology is proposed for designing and optimizing a lightweight mirror structure. Firstly, the initial designs are obtained combining global sensitivity factor mapping and local distribution optimization. Then, the optimal model is selected through multi-objective optimization and decision making. Subsequently, the FEA (finite element analysis) results indicate that, under the same mass, the proposed design exhibits better optomechanical performance. Finally, in practical applications, the approach presented in this paper outperforms the traditional design for each technological requirement, including a 62% reduction in RMS and a higher lightweight ratio. This method offers a kind of novel design and optimization process for space-based optomechanical lightweight structures.

Understanding Graphic Design Process in Visual Communication

From a chocolate wrapper design to a huge advertising hoarding, graphic design play a significant role in our daily life, which takes into consideration three important aspect of acceptance of a design - an aesthetic appeal, functional and semiotic approach. Graphic design encompasses the diverse set of design solution in visual form -from designing a logo, poster, signage to advertising design, web based design and many more that utilizes various visual elements, combining art and technology to communicate a message visually. Since it a coherent creative process of visual communication, the content of communication need to be streamed between the clients and the end user that takes into consideration certain aspect of structural stages or design process in order to get the best service and design solution to a problem. The paper highlights on the structure of the design process involve in a graphic design in bringing about a solution to a design problem within the practice of visual communication.

CMC strength and damage prediction considering thermal mechanic coupling effect

Continuous Fiber Reinforced Ceramic Matrix Composites (CMC) confront significant and undeniable elevated thermal gradient. In this study, a periodic RVE geometrical model was simplified based on the XCT scanning images of 2.5D woven CMC, and the model of the thermal structural strength of 2.5D woven CMC under the influence of fine-scale temperature fields was developed. In conjunction with the temperature distribution of the aero-engine turbine working state, ten sets of temperature field conditions were established and the model of thermal structural strength of 2.5D woven CMC under the influence of fine-scale temperature fields was developed. The effects of the overall temperature level, the form of the temperature difference and the size of the temperature difference on the tensile curve, the failure limits, the form of damage evolution, and the distribution of the failure unit at the time of failure of the 2.5D woven CMC were discussed. It was found that the temperature field induced by temperature difference in the thickness direction has a more significant effect on the tensile mechanical properties of the material, which is a key consideration for the structural design process using this material.

Aerostructural Wing Optimization Using a Structural Surrogate in a Coupled Adjoint Formulation

As the number of disciplines included in the multidisciplinary design-optimization process continues to increase, it is envisioned that some of the disciplinary tools will take the form of surrogate models, whereas others remain physics-based, depending on the requirements and stage of the design process. To simulate this in the context of an aerostructural optimization of an aircraft wing, the work presented herein features a high-fidelity aerodynamic flow solver, while a surrogate is employed to model the wing structure. This approach includes the evaluation of the sensitivities of both the aerodynamic and structural disciplines, using a coupled-adjoint formulation to enable gradient-based optimization. An important aspect of the method is that the surrogate is trained only once, prior to the optimization, and held fixed throughout. The surrogate in effect parameterizes the structural design process, and outputs the weight and stiffness of an optimized structure, given inputs of geometry parameters and sizing loads. To minimize the number of surrogate inputs and enable the representation of the entire structural design space, parameterized loads are used to build the surrogate. The method is applied to the optimization of the NASA Common Research Model, illustrating the effectiveness of the new approach.

Impact response characteristics and damage mechanism of continuous carbon-fiber-reinforced magnesium matrix composite materials

The continuous carbon-fiber-reinforced magnesium matrix composite (C_f/Mg) is a new type of composite material made of a magnesium alloy sheet and carbon-fiber-reinforced composite material with alternating layers. It has the advantages of high damage tolerance, light weight, and corrosion resistance, and has become the first choice of lightweight materials in aerospace, transportation, and other fields. Because impact-resistance serves as an important index for its structural design and performance stability, a continuous carbon-fiber-reinforced magnesium matrix composite with indirect bonding using a modified epoxy resin was designed in this study. Moreover, C_f/Mg was chosen to be the object of research through the selection of constituent materials such as magnesium alloys, carbon fibers, resins, and other properties, which matched the aim of realizing a lightweight material. With the help of hot-compression molding technology, dynamic impact mechanical behavior, and damage analysis technology, the structural design and preparation process optimization of epoxy resin carbon-fiber prepregs and magnesium alloy layer materials, as well as the dynamic impact mechanical response characteristics and damage evolution process under different impact energy conditions, were studied. Accordingly, through a combination of low-velocity impact experiments and numerical simulations, the effects of continuous multiple impacts at the same location with the same impact energy, as well as impacts with the same impact energy and different punch diameters, on the low-velocity impact damage behavior and dynamic impact response characteristics of C_f/Mg were investigated. The results of this study show that when the 5J impact is applied four times consecutively, the peak impact load gradually increases with the increasing number of impacts. Moreover, the peak impact loads of the second, third, and fourth impacts increase by 6.09%, 10.7%, and 14.5%, respectively, compared with the results of the first impact.

Simultaneous analysis of continuously embedded Reissner–Mindlin shells in 3D bulk domains

AbstractA mechanical model and numerical method for the simultaneous analysis of Reissner–Mindlin shells with geometries implied by a continuous set of level sets (isosurfaces) over some three‐dimensional bulk domain is presented. A three‐dimensional mesh in the bulk domain is used in a tailored FEM formulation where the elements are by no means conforming to the level sets representing the shape of the individual shells. However, the shell geometries are bounded by the intersection curves of the level sets with the boundary of the bulk domain so that the boundaries are meshed conformingly. This results in a method which was coined Bulk Trace FEM before. The simultaneously considered, continuously embedded shells may be useful in the structural design process or for the continuous reinforcement of bulk domains. Numerical results confirm higher‐order convergence rates.