Influence Of Design Parameters Research Articles

Sensitivity Analysis Contact Reliability of VH-CATT Cylindrical Gear and Its Reliability with Material Strength Degradation

VH-CATT cylindrical gear is a new transmission mechanism. In order to study the influence of design parameters and material strength degradation of the VH-CATT cylindrical gear on its transmission reliability. The Kriging surrogate model based on improved quantum particle swarm optimization (QPSO) algorithm was used to establish the limit state equation of contact stress for the VH-CATT cylindrical gear based on the stress-strength interference theory. The state equation of contact stress of the VH-CATT cylindrical gear was obtained with higher precision. Also, the strength degradation model with gamma distribution was established by using the P-S-N curve to estimate the parameters of the strength degradation model with gamma distribution. The reliability sensitivity of the VH-CATT cylindrical gear was analyzed by improved first order second moment method (AFOSM) based on the limit state equation of contact stress of the VH-CATT cylindrical gear, the reliability of gear considering strength degradation was studied by using the improved first order second moment method (AFOSM). The analysis results show that the failure rate decreases with the increase of pressure Angle, tooth width, modulus and tooth radius. The failure rate increases with increasing torque. Strength degradation has a certain influence on the reliability of gear and opinion. And the reliability of the gear is lower than that of the opinion, Strength degradation has a greater influence on the failure probability of gear, at the same time, the reliability of the gear pair decreases with the strength degradation. After 15000 hours of operation, the reliability of the gear pair is only 0.63155.

Multi-body dynamics model of crawler wall-climbing robot

In this paper, a crawler-type wall-climbing robot with negative pressure adsorption is designed. The dynamic model of the robot is established based on the method of discretizing the force load of the track shoe. The correctness of the kinematic model and dynamic model is proved by comparing two different ways of virtual prototype simulation and prototype experiment. According to the simulation results of the dynamic model and virtual prototype, the influence of design parameters on the motion performance of the wall-climbing robot is analyzed. The smaller the speed difference between the two tracks of the robot, the longer the gauge between the two tracks, and the greater the inclination of the adsorption wall, the larger the turning radius of the robot will be. The research content based on this paper can provide a new design optimization method and theoretical basis for improving crawler wall-climbing robots and crawler vehicles.

A study on porous nanocomposite graded plates using equivalent single layer and layerwise models

The static deflection of plates made from functionally graded materials integrating nanoparticles and porosities is analyzed. The models developed, consider equivalent single layer and layerwise approaches jointly with different shear deformation theories, and were implemented via finite element method. For the first-order shear deformation models, the shear correction factor is determined for each case. The models’ performances were verified and several case studies were considered to analyze the influence of parameters such as material properties, nanoparticles presence, and layers’ porosities distributions in the plates’ deflection. The results enable understanding the influence of design parameters as the models’ prediction trends.

Multi-objective optimization design and experimental investigation for a parallel liquid cooling-based Lithium-ion battery module under fast charging

• Parallel liquid cooling system is proposed for a battery module under fast charging. • Sensitivity analysis proves mini-channel depth as the most influential parameter. • Thermal control and energy cost can be enhanced by multi-objective optimization. • Volume energy density gets enhanced by 9.0% after optimization. • Accuracy of the numerical model and optimization is validated by experiments. Enhancing the charging rate capability is beneficial for the driving convenience of electric vehicles. However, high current rate charging causes inevitable severe heat generation, thermal inconsistency, and even thermal runaway. This study proposes a parallel liquid cooling system for a prismatic battery module to achieve the shortest charging interval and thermal safety under fast charging. Furthermore, a surrogate model with the objectives of the thermal performance and energy cost is constructed, the impact of some influential design parameters is explored through sensitivity analysis and response surface analysis. Moreover, a multi-objective optimization design is conducted for the optimal design selection. Finally, the optimal design is validated by experiments under 2.5C fast charging. Results demonstrate that mini-channel depth is the most influential design parameter on the cooling effect (70.8%), the temperature distribution uniformity (75.7%), and the energy cost (86.1%). Volume energy density, maximum temperature ( T max ), temperature standard deviation ( TSD ), and the energy cost ( W ) of the system are enhanced by 9.0%, 2.1%, 23.7% and 26.9%, respectively. Experimental validation proves that T max , TSD , and W of the battery module can be maintained within 33.1℃, 0.9℃, and 17.29 J, respectively. This study guides for the battery thermal management system design with enhanced efficiency and energy cost, especially during harsh operations.

Optimizing Design Parameters of PLA 3D-Printed Scaffolds for Bone Defect Repair

Current materials used to fill bone defects (ceramics, cement) either lack strength or do not induce bone repair. The use of biodegradable polymers such as PLA may promote patient healing by stimulating the production of new bone in parallel with a controlled degradation of the scaffold. This project aims to determine the design parameters maximising scaffold mechanical performance in such materials. Starting from a base cylindrical model of 10 mm height and of outer and inner diameters of 10 and 4 mm, respectively, 27 scaffolds were designed. Three design parameters were investigated: pore distribution (crosswise, lengthwise, and eccentric), pore shape (triangular, circular, and square), and pore size (surface area of 0.25 mm2, 0.5625 mm2, and 1 mm2). Using the finite element approach, a compressive displacement (0.05 mm/s up to 15% strain) was simulated on the models and the resulting scaffold stiffnesses (N/mm2) were compared. The models presenting good mechanical behaviors were further printed along two orientations: 0° (cylinder sitting on its base) and 90° (cylinder laying on its side). A total of n = 5 specimens were printed with PLA for each of the retained models and experimentally tested using a mechanical testing machine with the same compression parameters. Rigidity and yield strength were evaluated from the experimental curves. Both numerically and experimentally, the highest rigidity was found in the model with circular pore shape, crosswise pore distribution, small pore size (surface area of 0.25 mm2), and a 90° printing orientation. Its average rigidity reached 961 ± 32 MPa from the mechanical testing and 797 MPa from the simulation, with a yield strength of 42 ± 1.5 MPa. The same model with a printing orientation of 0° resulted in an average rigidity of 515 ± 7 MPa with a yield strength of 32 ± 1.6 MPa. Printing orientation and pore size were found to be the most influential design parameters on rigidity. The developed design methodology should accelerate the identification of effective scaffolds for future in vitro and in vivo studies.

Deployable toroidal structures based on modified Kresling pattern

Origami folding methods are increasingly becoming a vital factor in the advancement of deployable structures. The present study aims to the folding pattern design and deformation analyses of origami based deployable toroidal structures. A novel generalized algorithm is proposed to design six-fold line origami patterns for the development of circumferentially foldable/deployable toroidal structures. The proposed design approach is based on the mathematical optimization of the fold angles to accomplish perfect foldability and closure conditions. The foldability of the designed toroidal origami pattern is verified mathematically as well as by developing physical models. The angular deployment scheme is introduced to analyze the deformation behavior of the toroidal Kresling pattern numerically using pin-jointed wireframe technique. Later, a parametric study is performed to examine the influence of design parameters on the deployment strains under angular loading conditions, followed by a brief discussion about the absence of bistabililty phenomenon in the presented origami patterns. Moreover, the development procedure of paper based models of multi-story deployable toroidal sections is presented, and their shape accuracy is analyzed experimentally.

Impact load mitigation of meta-panels with single local resonator

This study investigates the influence of design parameters on the impact mitigation capacity of a new meta-panel that leveraged the coupled mechanisms of plastic deformation and local resonance to absorb energy from impact loading. The main objective is to minimize the force to be transmitted to the protected structures through mitigating the stress wave propagation by using local resonators. The meta-panel demonstrates the capability of filtering out the stress wave induced by impact loading with frequencies falling in its bandgaps. A numerical model is built and verified by the analytical solution with a good agreement in terms of the predicted frequency bandgaps. The meta-panel shows a substantial reduction in the mid-span deflection of the facesheets and an increase in the impact energy absorption as compared with the conventional sandwich panels. The peak reaction force of the meta-panel transmitted to the protected structure is also reduced significantly by more than 47% compared to its conventional counterparts. Furthermore, parametric studies are conducted to investigate the effects of the thickness of the hollow-truss bar, core material properties, and impact velocity on the meta-panels impact-resistant behaviour.

Novel Si/SiC heterojunction lateral double-diffused metal oxide semiconductor field effect transistor with low specific on-resistance by super junction layer

A novel Si/SiC heterojunction lateral double-diffused metal oxide semiconductor (LDMOS) field effect transistor with the low specific on-resistance (Ron,sp) by super-junction (SJ) layer (Si/SiC SJ-LDMOS) is proposed in this paper. On the basis of using N-Buffer layer to solve substrate assisted depletion effect (SAD), breakdown point transfer terminal technology (BPT) is realized by the deep drain structure of Si/SiC heterojunction and electric field modulation is carried out, which further improves the breakdown voltage (BV) of Si/SiC SJ-LDMOS, alleviates the contradictory relationship between the BV and the Ron,sp. Through ISE TCAD simulation, the result shows that with the same drift region length of 20 μm, the BV is increased from 114 V of conventional SJ-LDMOS (Cov. SJ-LDMOS) and 270 V of SJ-LDMOS with N-Buffer layer (Buffer SJ-LDMOS) to 374 V of Si/SiC SJ-LDMOS, increased by 228% and 38%, respectively. In addition, the Ron,sp of Cov. SJ-LDMOS, Buffer SJ-LDMOS and Si/SiC SJ-LDMOS are 46.26 mΩ cm2, 26.96 mΩ cm2 and 25.85 mΩ cm2, respectively. Moreover, the figure-of-merit (FOM) of proposed Si/SiC SJ-LDMOS device is 5.411 MW/cm2, which means the Si/SiC SJ-LDMOS has a better performance to break the silicon limit. The influence of design parameters on device performance is also discussed.

Shear behavior of flexible-sleeve perfobond strip connectors: Experimental and analytical studies

Flexible-sleeve perfobond strip connectors (SPBL), consisting of perfobond strip connectors (PBLs) and flexible plastic sleeves surrounding transverse rebars, are considered to be an effective and ductile solution in combining steel and concrete members together in composite structures. In order to evaluate structural performance of this type of shear connectors, push-out tests were performed on sixteen SPBL specimens with varying sleeve thicknesses and number of holes. Failure modes, load-slip curves, load-uplift displacement relationships, and strain history obtained from SPBLs tests are presented and discussed. The influences of design parameters on shear performance of SPBLs are analyzed. Experimental results indicated that the plastic sleeves surrounding transverse steel rebars effectively optimized the connector’s stiffness and ductility. As compare to conventional PBL connectors without plastic sleeves, the ductility coefficients of SPBL with a 2.0 mm- and 10.0- mm thick sleeve are increased by 77.2% and 26.1%, respectively, while the corresponding initial stiffness decreased by 27.6% and 46.9%, respectively. Results also indicated that the utilization of plastic sleeves effectively diminished the uneven effects among the multi-hole PBLs. Also, and as compared to triple-hole PBL connectors without flexible sleeves, providing a 2.0 mm- and 10.0 mm- thickness sleeves to transverse rebars decreased the uneven load coefficient by 26.3% and 89.7%, respectively. A comparison between experimental and analytical results using PBLs published formulas indicated that such existing formulas failed to address shear capacity of the multi-hole SPBLs. Accordingly, an analytical model that considers the uneven loadings and sleeve thickness effects that is capable of predicting the load-carrying capacity of multi-hole SPBLs was developed, and calibrated using experimental results.

New precast self-centering rocking shear wall with multiple hinged joints: Description and design approach for seismic protection of buildings

This paper proposes a novel precast self-centering shear wall with multiple hinged joints (PSCSWMHJ) as an alternative seismic resilient system, which is composed of pinned precast walls, pre-compressed disc spring devices (PDSD) and self-centering energy dissipation braces (SCEDB). It is featured by a dual self-centering system with the PDSD-wall component and the SCEDB resisting lateral loads. Seismic energies are expected to be mainly dissipated by S-shaped steel plate dampers installed in the SCEDB, while the precast walls are protected from damages. The damper is characterized by flexure-tension strengthening behavior that is beneficial to control structural displacement under strong earthquakes, and its seismic performance has been experimentally and numerically studied. The main objective of this study is to investigate rocking mechanism and seismic resilient design method for the PSCSWMHJ. In present study, mechanic models for the PDSD and the SCEDB are presented, and the SCEDB's hysteretic behavior is analyzed through numerical parametric studies. Rocking mechanism for the PDSDS-wall component and the PSCSWMHJ are theoretically revealed and numerically validated. Meanwhile, the influence of design parameters on their hysteretic behavior is discussed. The results show that the PSCSWMHJ has flag-shaped hysteretic curve and most of the energy is dissipated by dampers in the SCEDB. Subsequently, the step-by-step design procedure is proposed on the basis of energy balance concept for realizing seismic resilience of the PSCSWMHJ. Nonlinear dynamic analyses indicate that the design procedure is capable of achieving the expected performance objectives and the pre-selected yielding mechanism; the proposed PSCSWMHJ exhibits excellent self-centering capacity and good functional recoverability.

Tensile response of AP-PLY composites: A multiscale experimental and numerical study

This study presents the experimental and numerical characterization of composite laminates manufactured using a novel method known as Advanced Placed Ply (AP-PLY). The behavior of cross-ply and quasi-isotropic AP-PLY laminates under uniaxial tension is compared with that of baseline laminates. Stiffness is found to be unaffected by the preforming process, while the strength is dependent on the laminate configuration. A 3D multiscale numerical modeling framework is developed to capture the effect of the through-thickness fiber undulations present in the AP-PLY composites. The ability of the framework to accurately predict the stress–strain behavior and failure mechanisms at a relatively low computational cost is demonstrated. The approach is also exploited to investigate the influence of design parameters and improve the strength of the laminates. These results show the potential of the numerical framework to optimize the fiber placement preforming process to design AP-PLY components for structural applications.

Mechanics-Guided Design of Wearable Network Heaters for Bio-Integrated Applications

Abstract Wearable heaters that can retain conformal contact with human skin have attracted significant attention in recent years due to their enormous potential in thermotherapy. Existing strategies for wearable heaters are constrained by fixed configurations or dimensions, which limit their broad utilities in bio-integrated applications requiring heaters of various sizes. Here, we report a mechanics-guided design of wearable network heaters based on the lattice structure with the negative Poisson’s ratio combined with the uniaxial stretch, which allows for the easy realization of heaters with different sizes and relatively uniform heating performance. Theoretical and computational mechanics studies reveal the fundamental aspects of the design and operation of the network heaters. Thermal analyses of the network heaters integrated with human skin are performed to investigate the influences of design parameters on the skin temperature. This study offers an easy route for wearable network heaters and provides design guidelines for their fabrications.

Dynamics of two floating wind turbines with shared anchor and mooring lines

Floating wind farms present the opportunity to harvest wind resources located in deep water sites. Shared mooring designs can contribute in making floating wind energy more cost-competitive, and it is important to understand the new system dynamics that arise. We are presenting here HAWC2Farm, an extension of HAWC2 that can model multiple wind turbines with shared mooring lines. We apply the new modeling capabilities to simulate two 15 MW floating wind turbines on spar floaters with shared mooring lines. We consider two different sites and we identify and compare the natural frequencies and mode shapes of the shared mooring designs with those of an individual moored turbine. Furthermore, we investigate the influence of design parameters on the systems’ natural frequencies and we show that it is possible for a shared mooring design to achieve similar characteristics as a single turbine design. Finally, we test the response of the shared mooring design in steady wind and regular waves and find that the surge displacement of the upstream turbine and its mooring line loads are considerably larger compared to the single turbine case.

Multi-objective optimization of cross laminated timber-concrete composite floor using NSGA-II

Cross-laminated timber (CLT) is an engineered wood product made of multiple glued layers in the form of a panel suitable for flooring systems. CLT can also be mechanically connected to the concrete layer using the connector systems to create a CLT-concrete composite (CCC). This concept enhanced the structural performance of the floor and could be adopted for mid-and high-rise buildings. However, the design of the CCC floor involves the optimization of multiple structural and non-structural elements. In this study, we tackle the gap in the literature by carrying out a multi-objective optimization of the CCC floor with notched connectors by minimizing total thickness, total weight, and total material cost considering structural, vibration comfort, and especially, fire conditions constraints using the well-developed genetic algorithm (NSGA-II). The optimal solutions are presented in the Pareto fronts of multiple floor spans and cost ratio timber/concrete. The study also gives insight into the influence of design parameters and the governing design constraint. However, we only focus on one type of floor (CCC) and do not implement the environmental aspect of the structure.

Residual displacement demand for non-degrading bilinear SDOF oscillators with self-centering viscous-hysteretic devices

The self-centering viscous-hysteretic device (SC-VHD) is a high-performance self-centering system that was recently developed to reduce structural residual displacement and damage during severe earthquakes. This study focuses on developing a residual displacement ratio C r spectrum and a residual displacement estimation method for non‐degrading bilinear SDOF oscillators with SC-VHDs. Statistical analysis is conducted to investigate the effect of design parameters on the constant-ductility residual displacement ratio C r spectrum under near-fault pulse-like earthquake ground motions (NFPE) and far-fault earthquake ground motions (FFE). Based on statistical data, a formula for the mean C r spectrum is proposed. Subsequently, an iterative calculation method for residual displacement is presented according to the equivalent linearization method and the proposed mean C r spectrum formula. Finally, using the iterative calculation method, the residual displacement of a two-story steel moment-resisting frame (MRF) with SC-VHDs is predicted, demonstrating its application. The results indicate that the mean C r spectrum under the NFPE is significantly larger than that under the FFE. Besides, the mean constant-ductility C r spectrum decreases with increasing post-yield strength ratio, ratio of preload to yield strength, ratio of loading stiffness to elastic stiffness increases, or ratio of unloading stiffness to loading stiffness, but increases with increasing viscous damping ratio. When estimating the C r spectrum, increasing the ductility ratio and decreasing the ratio of preload to yield strength can both reduce record-to-record variability. Both the formula for the mean C r spectrum and the iterative calculation method for residual displacement are validated by comparing with statistical data. • The influence of design parameters on the residual displacement C r spectrum is investigated. • A formula for the normalized mean C r spectrum is developed. • An iterative calculation method for residual displacement is proposed. • An example application is used to validate the calculation method.

Increased Robustness to Delay in Incremental Controllers Using Input Scaling Gain

The main advantage of the incremental dynamics formulation is its property of replacing state-dependent aspects of the system dynamics by measurements, solely requiring modeling the input-dependent dynamics. However, incremental controllers assume that state derivative measurements are available. The lack of accurate sensors and communication delay may appear as limitations for the use of incremental techniques. This article applies a second-order differentiator (SOD) for estimating state derivatives and attenuate measurement noise, and an input scaling gain (ISG) for attenuating the effects of high-frequency noise and delay in the feedback loop. A complete analysis of the combined solution is carried out using an incremental nonlinear dynamic inversion (INDI) strategy. First, a simple linear single-input single-output model is used to evaluate the influence of design parameters in the closed-loop response and stability. Then, the combined SOD and ISG approach is illustrated in a more complex case application, where INDI is used to control the lateral motion of an autonomous airship, results of which corroborate the ISG as an asset to increase the maximum delay allowed in the feedback loop.

Methodology for Assessing the Energy Efficiency of Electrotechnical Complexes in the Separation of Wax Raw Materials

A technique for assessing the energy efficiency of operational impacts in the separation of organic wax contaminants is presented. Promising methods for separating media with complex types of bonds are proposed. Dependences characterizing the energy efficiency of methods for the separation of wax raw materials are determined. Mathematical models in the form of quadratic polynomials are obtained, which describe the influence of design parameters on energy characteristics.

Design and Optimization of a New Anti-reflux Biliary Stent With Retractable Bionic Valve Based on Fluid-Structure Interaction Analysis.

Duodenal biliary reflux has been a challenging common problem which could cause dreadful complications after biliary stent implantation. A novel anti-reflux biliary stent with a retractable bionic valve was proposed according to the concertina motion characteristics of annelids. A 2D equivalent fluid-structure interaction (FSI) model based on the axial section was established to analyze and evaluate the mechanical performances of the anti-reflux biliary stent. Based on this model, four key parameters (initial shear modulus of material, thickness, pitch, and width) were selected to investigate the influence of design parameters on anti-reflux performance via an orthogonal design to optimize the stent. The results of FSI analysis showed that the retrograde closure ratio of the retractable valve primarily depended on initial shear modulus of material (p < 0.05) but not mainly depended on the thickness, pitch, and width of the valve (p > 0.05). The optimal structure of the valve was finally proposed with a high retrograde closing ratio of 95.89%. The finite element model revealed that the optimized anti-reflux stent possessed improved radial mechanical performance and nearly equal flexibility compared with the ordinary stent without a valve. Both the FSI model and experimental measurement indicated that the newly designed stent had superior anti-reflux performance, effectively preventing the duodenobiliary reflux while enabling the bile to pass smoothly. In addition, the developed 2D equivalent FSI model provides tremendous significance for resolving the fluid-structure coupled problem of evolution solid with large deformation and markedly shortens the calculation time.

Prediction of the shear strength of RC beam-column joints using new ANN formulations

Beam-column joint is a key part for reinforced concrete (RC) frame building structures under the impact of severe lateral actions of seismic or wind loading. Prior works indicate that there is lacking in the direction of formulation of new mathematical models to predict RC joints strength by artificial neural network (ANN) considering influential design parameters. Present endeavor is devoted to establish new empirical ANN models to estimate shear strength and failure mode for RC exterior and interior beam-column joints. These models were relied on training, testing and validation of a database of over 200 experiments, for the performance of RC joints, using ANN. More than 20 parameters, related to the geometry and loading of the joints, were selected as inputs for these models; but four effective inputs were used in the formulation of the final ANN models. The outputs for ANN models were compared to those counterparts of the commonly utilized models given in codes and other recent studies. This calculation confirms the reliability of current ANN mathematical models and their outstanding performance. Moreover, comparison shows that the proposed models were precise in including the effective independent variables in these models and avoiding the shortcoming of previous models.

Influence of design parameters on engineering properties of angular shaped fly ash aggregates

Fly ash of thermal power plants substitute’s construction materials and can help to preserve non-renewable resources. In the construction industry, more particularly in concrete and road construction, a huge quantity of aggregate is being used. Fly ash aggregate is a unique alternative for the construction industry at present. However, the properties of fly ash aggregate are mostly controlled by the type and dosage of additive used besides the characteristics of ash and curing method adopted. In the present study, specimens from various combinations of fly ash with hydrated lime, ground granulated blast furnace slag, and cement were prepared at maximum dry unit weight with optimum moisture content and cured by hot water curing method. The cured specimens were crushed to prepared angular shaped fly ash aggregates. The influence of the binding additives on the unconfined compressive strength of mixes and aggregate impact value was studied. Measured engineering properties were also analyzed through a micro-level study. The addition of lime enhanced the unconfined compressive strength of mixes and impact value of aggregates, whereas, replacement of lime with the ground granulated blast furnace slag and cement reduced the strength of the mixes. Unconfined compressive strength value of mixes shows the inverse relationship with impact value of aggregate prepared from that mixes and a correlation between unconfined compressive strength and aggregate impact value has been proposed. Moreover, the effect of moisture content and pressing force on compressive strength and aggregate impact value was also investigated on optimum mixes. From these experimentations, the optimum combinations of fly ash-additive mixes, the optimum value for moisture content, and pressing force were chosen; and angular shaped fly ash aggregates were produced by hot water curing method. Furthermore, the various physical properties, mechanical properties and durability index of these fly ash aggregates are discussed and compared with the Indian standard specifications. The leaching behavior of these aggregates was also examined in this study. The addition of lime gives better results compared to cement and ground granulated blast furnace slag and use of lime seems to be more cost-effective. Thus, these cold bonded fly ash aggregates with significant strength may find prospective use in civil engineering construction sector.