Design Of Structural Components Research Articles

Shear buckling behaviour of sinusoidal corrugated web girders with stiffened circular openings

The mechanical properties and failure behaviours of three different specimens of sinusoidal corrugated web girders with stiffened circular openings were investigated experimentally and numerically. The experimental outcomes showed similarities in the mechanical properties and failure model of the specimens, despite differences in the geometric dimensions. The numerical simulations further confirmed the buckling as well as post-buckling behaviours of the experimental results. The influence of initial geometric imperfections on the shear buckling load of the corrugated web girders was quantified and neglecting geometric imperfections led to an overestimation of the actual shear load capacity, emphasizing the importance of considering imperfections in the design of structural components. The investigation results showed that the shear load capacities of the girders were significantly affected by the thickness of the opening stiffeners, and that the presence of openings reduced the load carrying capacity and the overall stiffness of the beams, whereas the existence of opening stiffeners increased both the ultimate load bearing capacity and the global stiffness. However, the strengthening effect of the opening stiffener becomes less pronounced beyond a specific thickness. Besides, a comparison between hand calculations and numerical simulations show that the recently developed calculation method provided a more reliable prediction of the shear buckling resistance of corrugated web with stiffened openings. This investigation provides valuable guidance on the shear buckling behaviour of sinusoidal corrugated web girders with circular opening stiffeners, thus benefiting the design and analysis of steel structural components with sinusoidal corrugated web.

On the dynamics of the elastic concrete systems reinforced by advanced nanocomposites

This work investigates the vibrational properties of doubly curved elastic concrete panels reinforced with multi-hybrid nanocomposites under in-plane loading. These cutting-edge materials use the advantages of several nanocomposites to produce greater performance by integrating many kinds of nanofibers and nanotubes to boost mechanical qualities. The study focuses on the effects of these reinforcements on the dynamic behavior of doubly curved panels, which are a typical structural component in contemporary engineering applications including civil infrastructure, automotive, and aerospace. The study investigates the natural frequencies and dynamic stability of the panels under in-plane stress circumstances using a thorough analytical method. The complicated geometry and material heterogeneity are modeled using mathematical modeling, which offers comprehensive insights into the impact of nanocomposite reinforcements. The findings show that, in comparison to conventional concrete panels, multi-hybrid nanocomposites considerably increase stiffness characteristics and vibrational performance. The results highlight the potential of these novel materials to transform structural component design and application, resulting in more robust and effective engineering solutions. By improving our knowledge of hybrid nanocomposite behavior under dynamic stresses, our study opens the door to a wider use of these materials science and engineering principles in materials science and engineering.

MnFe2O4/Fe3O4/PANI/rGO heterogeneous nanocomposites: Outstanding dual-broadband nano-coating microwave absorbers

In this study, MnFe2O4/Fe3O4/PANI nanocomposites were synthesized via hydrothermal and coprecipitation methods and decorated on reduced graphene oxide (rGO) sheets with three weight ratios (1:1), (2:1), and (3:1) for MnFe2O4/Fe3O4/PANI versus rGO. FESEM images indicate a random distribution of MnFe2O4/Fe3O4 and PANI components on the rGO sheets. The designed superparamagnetic nanocomposites, MnFe2O4/Fe3O4/PANI/rGO, exhibit multi-reflections, strong interfacial polarizations, scattering of incident microwaves, and multiple magnetic resonances, which results in superior absorption performance. This is due to the structural design and distribution of different components providing various interfaces, high specific surface area, and different magnetic and dielectric components. The microwave absorption properties are evaluated in the frequency range of 1–18 GHz (L, S, C, X, and Ku bands), from electromagnetic parameters according to transmission line theory. Our results show that (MnFe2O4/Fe3O4/PANI)/rGO (1:1) presents the highest reflection loss, −108.71 dB, at 17.8 GHz with a thickness of 4.2 mm and bandwidth of 3.2 GHz. Interestingly, (MnFe2O4/Fe3O4/PANI)/rGO (3:1) shows a broad absorption bandwidth of 5.6 GHz for a thickness of only 2.2 mm, having a remarkable reflection loss of −95.52 dB at 17.8 GHz. Our study introduces a novel approach for the successful design and preparation of multi-dimensional graphene-based quaternary nanocomposites compromised from lightweight microwave absorbers, with numerous heterogeneous interfaces and defects resulting from interfacial engineering that have promising potential applications in broadband microwave absorption.

Fracture behaviors of the 1500 MPa-grade anti-oxidation hot-stamped steel: Measurement, numerical simulation and experimental validation

Ultra-high strength hot-stamped steel has been increasingly and widely used for the improvement of the collision safety and lightweight level. The 1500 MPa-grade anti-oxidation hot-stamped steel (AHS-1500), as a newly developed hot-stamped steel, is promising in the automotive industry due to its advantages of anti-oxidation, high strength, high hardenability, and no coating. It is necessary to figure out its fracture failure behaviors and further predict the fracture risk for promoting the large-scale application. In this paper, the fracture behaviors of the AHS-1500 steel plate are investigated by experiments and simulation. The fracture tests are conducted under static and dynamic loads by considering various stress states, namely uniaxial tension, notched static tension, shear, punching, center-hole static tension, and VDA bending. The fracture failure behaviors are obtained. Moreover, an Swift+Hockett-Sherby combined hardening model is adopted to extrapolate the post-necking flow stress to obtain the stress-strain relation at large strains. A fracture failure model is further established based on the GISSMO fracture failure criterion to accurately describe the failure behaviors under various stress states. The nonlinear fracture failure strain and the necking instability strain are determined with the consideration of the influence of element size and strain rate. Finally, the three-point bending experiment of a cap beam part is conducted and simulated to verify the effectiveness of the proposed model. The simulated results match the experimental ones very well, with the absolute relative errors of only 1.4 % and 4.6 % for the peak force and peak displacement, respectively. This research is favourable for contributing to high-precision numerical analysis for the design of automotive structural components and providing technical support for large-scale promotion of the AHS-1500 steel.

Assessment of a Simplified Methodology for Preliminary Blast-Resistant Design of Insulated Precast Concrete Wall Panels

Abstract A Blast loading history can be represented by the peak pressure value and the impulse. Combinations of pressure and impulse of various blast loading scenarios can be collected to draw a pressure-impulse (P-I) curve that corresponds to a level of damage of a blast-resistant structural component. The P-I curve is typically used for a preliminary design or assessment of blast resistance structural components. Generating a P I curve for a given structural component and level of protection requires repeatedly ru nning a single degree of freedom system (SDOF) model, which can be tedious for early design stages. Hence, a simplified approach (i.e., the normalization approach) was utilized to promptly generate the P- I curve for insulated precast concrete wall panels, which relies on shifting a control P I curve using normalization factors. The generated P-I curves using the normalization approach are validated with the traditional SDOF approach curves; 95% of the examined insulted panel configurations have an error between +/-7%. As a result of the reached low error percentages, a spreadsheet- design tool was developed using this approach. The tool can further enable rapid evaluation of the performance of insulated precast concrete panels under blast loading during the preliminary design phase.

Optimal design of structural engineering components using artificial neural network-assisted crayfish algorithm

Abstract Optimization techniques play a pivotal role in enhancing the performance of engineering components across various real-world applications. Traditional optimization methods are often augmented with exploitation-boosting techniques due to their inherent limitations. Recently, nature-inspired algorithms, known as metaheuristics (MHs), have emerged as efficient tools for solving complex optimization problems. However, these algorithms face challenges such as imbalance between exploration and exploitation phases, slow convergence, and local optima. Modifications incorporating oppositional techniques, hybridization, chaotic maps, and levy flights have been introduced to address these issues. This article explores the application of the recently developed crayfish optimization algorithm (COA), assisted by artificial neural networks (ANN), for engineering design optimization. The COA, inspired by crayfish foraging and migration behaviors, incorporates temperature-dependent strategies to balance exploration and exploitation phases. Additionally, ANN augmentation enhances the algorithm’s performance and accuracy. The COA method optimizes various engineering components, including cantilever beams, hydrostatic thrust bearings, three-bar trusses, diaphragm springs, and vehicle suspension systems. Results demonstrate the effectiveness of the COA in achieving superior optimization solutions compared to other algorithms, emphasizing its potential for diverse engineering applications.

Multiscale 3D displacement field measurement using stereo digital image correlation on a fractal speckle pattern

AbstractEven though the simulations used to predict failure are becoming increasingly predictive, complex multiaxial loading tests are still required to validate the design of structural components in a wide range of industries. Large specimen testing often requires two different scales. A global Far Field to obtain boundary conditions and a local Near Field to evaluate strain gradients around discontinuities such as bolts, notches… The main goal of this study is to provide a continuous displacement over the whole specimen surface integrating data from multiple cameras. In this paper, we propose a new methodology that generates 3D displacements determined by finite‐element stereo digital image correlation in the Near Field and in the Far Field using a unique fractal speckle pattern and an off‐line determined texture. The displacements are obtained in the same coordinate system and on the same mesh. Satisfactory data fusion from both Near Field and Far Field images of a biaxial test on a notched laminate composite was obtained with a refined mesh at the notch tip. This methodology can be applied to any tests requiring multiple camera systems and will support the use of the finite‐element digital image correlation framework as an experimental‐numerical efficient technique.

Deformation localisation in ion-irradiated Fe and Fe10Cr

Determining the mechanisms for irradiation-induced ductility loss is crucial for the design of reactor structural components. Here, the deformation characteristics around nanoindents in Fe and Fe10Cr irradiated with Fe ions to ∼1 displacement-per-atom at 313 K are non-destructively studied. Slip steps surrounding the nanoindents indicate that deformation is localised in the irradiated materials. Lattice rotation and strain fields near the indent site show over 87% confinement of plasticity in the irradiated material. Cr has little effect on the irradiation-induced changes in pile-up topography and deformation fields, suggesting it has limited impact on retaining strain hardening capacity and reducing irradiation-induced embrittlement.

Fatigue Crack Growth Rates and Crack Tip Opening Loads in CT Specimens Made of SDSS and Manufactured Using WAAM.

Additive manufacturing offers greater flexibility in the design and fabrication of structural components with complex shapes. However, the use of additively manufactured parts for load-bearing structural applications, specifically involving cyclic loading, requires a thorough investigation of material fatigue properties. These properties can be affected by many factors, including residual stresses and crack tip shielding mechanisms, which can be very different from those of conventionally manufactured materials. This research focuses on super duplex stainless steels (SDSSs) fabricated with wire arc additive manufacturing (WAAM) and investigates their fatigue crack growth rates and the net effect of crack tip shielding mechanisms. Using the compliance-based method, we measured crack tip opening loads in compact tension (CT) specimens with cracks propagating longitudinally and transversely to the WAAM deposition direction. It was found that fatigue crack growth rates were very similar in both directions when correlated by the effective stress intensity factor range. However, the differences in crack tip opening loads explain a quite significant influence of the deposition direction on the fatigue life.

Comparison of the structure and physicochemical properties of ZrO2 based crystals partially stabilized with Y2O3, Gd2O3 and Sm2O3

The phase composition, density, microhardness and fracture toughness of (ZrO2)1-x(R2O3)х crystals (where R = Y, Sm and Gd) for x = 0.02–0.04 have been compared. The crystals have been grown using directional melt crystallization in a cold crucible. The phase composition of the crystals has been studied using X-ray diffraction and Raman spectroscopy. The microhardness and fracture toughness of the crystals have been evaluated by means of indentation. At stabilizing oxide concentrations of ≥ 2.8 mol.% for Y2O3 and Gd2O3 and ≥ 3.7 mol.% for Sm2O3 the crystals have densities close to the theoretical ones and contain two tetragonal phases. At lower stabilizing oxide concentrations the crystals contain the monoclinic phase. The fracture toughness of the tetragonal crystals increases with the ionic radius of the stabilizer. The highest fracture toughness values achieved when stabilized by a specific oxide are 11.0, 13.0 and 14.3 MPa·m1/2 for the 2.8YSZ, 2.8GdSZ and 3.7SmSZ crystals, respectively. The fracture toughness proves to depend on the crystallographic orientation of the crystals. The results of this work can be used in the design and fabrication of various structural components and devices.

Consideration of surface roughness during the design of internal structures for fluid transport produced by additive manufacturing of PEEK

Additive manufacturing offers new possibilities for the design of structural components used in fluid transport. Sections of hydraulic manifolds or hydraulic blocks, parts of fluid pumps or hydraulic motors can now be manufactured with details which were not achievable with conventional manufacturing technologies, e.g., optimization of internal bends to minimize pressure drops or decrease peaks in velocity fields of fluids. However, as geometric features influence operational conditions of structural elements, pressure drop and velocity field also depend on the wall roughness of internal bends. This feature thus also has to be taken into account when designing the internal structure for the given fluid and operating conditions. In this paper, a study on surface roughness produced with additive manufacturing of polyether ether ketone (PEEK) is presented. PEEK is known for its excellent thermal and mechanical properties, resistance to wear, chemicals, and temperature which makes it an exciting material choice for structural elements with exceptional performance characteristics. First, flow of water and oil through a round pipe produced with additive manufacturing has been simulated. Two models have been used in simulations, a simplified pipe with a prescribed wall roughness and a detailed pipe with modeled surface roughness. Pressure losses and velocity fields in the pipe were then calculated. Finally, an experiment has been set to measure the pressure losses which are compared to the simulated values.

Latent Diffusion Models for Structural Component Design

Recent advances in generative modeling, namely Diffusion models, have revolutionized generative modeling, enabling high-quality image generation tailored to user needs. This paper proposes a framework for the generative design of structural components. Specifically, we employ a Latent Diffusion model to generate potential designs of a component that can satisfy a set of problem-specific loading conditions. One of the distinct advantages our approach offers over other generative approaches is the editing of existing designs. We train our model using a dataset of geometries obtained from structural topology optimization utilizing the SIMP algorithm. Consequently, our framework generates inherently near-optimal designs. Our work presents quantitative results that support the structural performance of the generated designs and the variability in potential candidate designs. Furthermore, we provide evidence of the scalability of our framework by operating over voxel domains with resolutions varying from 323 to 1283. Our framework can be used as a starting point for generating novel near-optimal designs similar to topology-optimized designs.

Biaxial Testing of EPDM Rubbers for Automotive Applications Using a Uniaxial Testing Machine

The FE-based structural design of components made of rubber materials requires an experimental characterization to calibrate a proper hyperelastic material model. A strain energy density (SED) parameter is typically adopted to describe the hyperelastic behavior of isotropic rubbers. This can be written as a function of the strain tensors, the strain invariants or the stretch ratios and proper material parameters. The latter must be calibrated on experimental data generated by testing rubber materials under different loading conditions, typically two among uniaxial tension, pure shear and biaxial tension. In this context, the mechanical behavior of Ethylene–Propylene–Diene Monomer (EPDM) rubbers, both in the dense and expanded configurations, which are typically employed to manufacture automotive seals, has been investigated. First, uniaxial tension tests have been performed. Afterwards, a new fixture has been developed to perform equi-biaxial tension tests using a uniaxial testing machine. The fixture has been adopted to test EPDM cruciform specimens under equi-biaxial tension loading. Finally, both uniaxial and equi-biaxial data have been employed to fit a Mooney–Rivlin material model for each tested EPDM rubber, which has been validated by comparing the results of FE simulations with the experimental ones.

Numerical Study of Crack Prediction and Growth in Automotive Wheel Rims.

Finite element analysis has become an essential tool for simulating and understanding crack growth. This technique holds significant importance in the field of mechanical engineering, where it finds wide application in the design and optimization of structural components and material properties. This work began with the identification of critical zones and estimated the number of load life repeats through fatigue analysis, specifically applied to automotive rims utilizing innovative finite element methods. To investigate crack behavior, we are used the Extended Finite Element Method (XFEM) with the volumetric approach to compute the Stress Intensity Factor (SIF). The results obtained by our study align closely with experimental tests in terms of detecting the critical zone where a crack can appear. Our findings contribute to the understanding of fatigue behavior in automotive rims, offering new insights into their structural integrity and performance under various load conditions.

Notch structural stress theory: Part II predicting total fatigue lives of notched structures

Notch fatigue problems are among the most common topics for the reliability analysis and structural design of mechanical engineering components. In previous work, we proposed the Notch Structural Stress (NSS) method based on fracture mechanics for reflecting the notch effect on fatigue crack propagation lives. However, like other regular fatigue assessing procedures, NSS also cannot accurately predict the fatigue life of notched structures with slower stress gradients due to the inconsistent slope of their S-N curves. This paper presents the Theory of Notch Structural Stress (TNSS) for predicting total fatigue lives of notched structures, which overcomes the life prediction limitations caused by slope differences in S-N curves and constructs a life-predicting frame suitable for different notch types even including plain and sharp notches. Compared with the often-used stress-concentration-assessing procedures, TNSS provides a more effective consolidation of the S-N data from different notch types, mostly since it takes both Initiation and Propagation state resistance into account at the same time.

STUDENT MADE INFRASTRUCTURE IN RURAL CONTEXTS - LA ESTRELLA STEEPLE DESIGN BUILD PROJECT

The Design/Build Methodology in the Education of Architecture is an alternative to traditional and theoretical training where real projects and construction takes place. This paper focuses on a case study from the School of Architecture course “Introducción a la Construcción” at the Pontificia Universidad Católica de Chile. Its main feature is exploration on timber construction through a direct hands-on experience and development of prefabricated built projects. Timber has been used as the predominant building material since it allows to explore concepts of prefabrication, modular coordination, and structural performance. This intuitive design approach is complemented by a low-tech and low-cost solution according to the local context. Recently the course has realigned its focus to community-oriented projects outside the university in a process that entails complex management and technical issues. The project considers a steeple structure commissioned by La Estrella parish and the impact of project´s brief constraints on the timber structure in terms of: design and prefabrication process: brief constraints plus available design tools were applied to on-site and off-site construction methods to allow quick assembly. A participative and iterative process through design and testing of different timber structural components developed by groups of students; management issues: communication, consultants and construction management by the academic staff and students; relationship with community: this process includes participatory design, community engagement and participation. Conclusions drawn from this project show a successful experience of timber building systems applied to this methodology. Built results have exceeded original expectations while the engagement between the student project and the benefiting community constitute a successful experience in the exploration of these teaching strategies. Involvement of students in management process is an aspect that needs further development as a relevant feature to be considered on future off-campus projects.

Development of a novel perforated type precision metering device for efficient and cleaner production of maize

This research presents a filling method that strips the kernels from the seed group to address the poor performance and energy efficiency of the mechanical maize metering devices at high-speed operating conditions. In addition, it advances the design of a novel perforated type precision seed-metering device. The quantity and posture of seed filling are restricted by the perforated ring, which creates a dispersed particle flow, thus enhancing the filling effect of the seeding plate and reducing energy consumption. The structural design of critical components is completed, and the principle of improving performance and energy efficiency is analyzed. The DEM simulation and bench experiment assisted in analyzing the effects of operating parameters on seed dynamic characteristics, seeding plate's filling performance, and operational energy consumption. Finally, the optimal parameter combination is determined. The result demonstrates that the number of teeth in the perforated ring was 21, accompanied by an improved seed-filling effect and lower energy consumption. The metering performance was optimal when the tooth length of the perforated ring was 8.65 mm, the center angle of the teeth was 8°, and the operating speed was 13.55 km/h. Moreover, the qualified rate was 94.5%, the multiple rate was 2.7%, and the leakage rate was 2.8%. The operating speed was in the range of 8–14 km/h, the qualified rate of the perforated seed-metering device was higher than 92.7 %, the leakage rate was lower than 5.4 %, the multiple rate was lower than 3.5 %, and the coefficient of performance was more than 9.2. Its energy efficiency was significantly better than that of the picker finger seed-metering device and the air-suction seed-metering device, thus satisfying the demands for an efficient and cleaner production of maize.

Actuality and technology prospect of using perovskite quantum dot solar cells as the photovoltaic roof

PV architecture is the main form of low-carbon architecture, it has great significance for realizing zero-energy buildings (ZEB) The photovoltaic (PV) roofing project is an important form of PV architecture. The materials currently on the market such as silicon and copper indium gallium selenide (CIGS) are unable to meet both the cost and aesthetic requirements of architectural design. So, a new technical scheme has been emphasized to eliminate the color inconsistency between the PV roofing and building and costing by using perovskite quantum dots solar cells（PQDSC） in PV facilities. The technical requirements of PV roofing are sorted out from the architectural perspective based on general standards. PQDSC has the potential to meet regulatory requirements due to its flexibility, light weight color transparency. Then solutions to the underlying technical problems such as the structural design of PV building components, PV basic materials, and color adjustment of PV modules are analyzed and summarized. The potential of PQDSC for applications in PV roofing projects has been largely prospected due to the promising directions they reveal for further research.

Low-cycle fatigue testing and microstructure of high strength-ductility structural steel materials

The well-known tradeoff between strength and ductility is a key issue in the large-scale engineering application of steel materials to resist fatigue due to earthquakes and other vibrational excitations. The steel production industry provides a vast range of technologies to achieve the desired performances. Through experimental research, it was found that FeCrNi-based high-ductility steel (HD-S) can demonstrate remarkable hysteresis behavior due to extensive deformation capacity of strain-hardening until the ultimate fracture, compared to industrially manufactured high-strength steel (HS-S) with the level of 1 GPa in yield strength. The balance between strength and ductility can be realized by slightly adding the percentage of Ni by 5% to achieve a ductile hysteresis behavior. Moreover, the HD-S specimens exhibit greater resistance to low-cycle fatigue with large plastic amplitude. By developing a new damage evolution law based on instantaneous damage differential during nonstationary fatigue history, the fatigue life of materials is extended into the inelastic hinges of flexural beams/origami components. The proposed approach enables the fatigue design of steel structural components with desirable disaster-prevention capacities for complex steel structures.

A phase-field fatigue fracture model considering the thickness effect

Modern aero-engine turbine structures often have variable-thickness geometries (e.g., turbine structures with complex cooling systems) that pose a significant challenge to crack analysis. The phase-field fracture method is a numerical method that has recently received considerable attention. However, phase-field fatigue fracture models that consider the effect of thickness are still lacking. To address this problem, this paper proposes a modification of the fracture toughness in the phase-field fatigue model by introducing a relationship function between material fracture toughness and thickness (Gc-B curve). We use reference experimental data to fit the Gc-B curve of GH4169 and predict the fracture toughness of specimens with other thicknesses. The predictions of the proposed model agree well with the experimental results reported in the literature. This achievement contributes significantly to the structural safety design and life prediction of aero-engine components.