Sensitivity Of Structural Parameters Research Articles

Study on Structural Parameter Sensitivity and the Force Transmission Mechanism of Steel–Concrete Joints in Hybrid Beam Bridges

In this study, a refined model of the Shanghai Damaogang Bridge’s (hybrid beam type) box deck joints is established. The correctness of the model is verified by construction monitoring. For the front and back bearing plates, the force performance of the joint members under the most unfavorable loads is investigated, and the force transmission mechanism is analyzed. The influence of the bearing plate thickness and the joints’ stiffness on the stress distribution of the joint members, the internal force of the joints, and the force-transfer efficiency is investigated by the method of controlling variables, and the optimal structural parameters of the nodes are also studied. The results show that, within the proximity of the back bearing plate, the thickness of the back bearing plate affects stress distribution in the joint. The increased stiffness of the welding studs makes the range of shear force along the bridge direction of the top and bottom welding studs larger, and the longitudinal distribution of welding stud shear force is more uneven. The concrete structure bears a higher proportion of the internal force in the joint compared to the steel structure.

Mechanical properties prediction and design of curved beams by neural network

It is known that curved beams are used widely in vibration isolation and noise reduction. The curved beam can show bistable, negative stiffness and other mechanical characteristics in the compression process through design. The preflex beam absorbs energy during the multi-state jump process and can recover its initial configuration after undergoing loading and unloading, so it is an ideal energy absorb component. In this paper, preflex beams are designed and the mechanical properties are studied and predicted by neural network. Firstly, a large number of finite element models for sinusoidal preflex beams are built by using Python randomly selected the parameters of beams. Secondly, the dataset corresponding to the parameters of the beams and mechanical properties is established. The variation trend of mechanical properties such as initial stiffness, force threshold, negative stiffness and total absorbed energy with the change of structural parameters and the sensitivity of structural parameters to the above mechanical indexes are obtained. Thirdly, by substituting the data set into the artificial neural network, the trained neural network can predict the mechanical properties of the beams within the allowable error range. At last, a new type of preflex beam with porous section is proposed in order to optimize the specific absorbed energy of the preflex beam. After data screening and optimization, the specific absorbed energy of the porous preflex beam is increased by 15.56 % compared with the beam whose section without porous. The results obtained show that the data-driven method can greatly shorten the structural design time and expand the design space. This study will provide a theoretical basis for the wider application of preflex beams in engineering field.

Low-loss and high-sensitivity surface plasmon resonance sensor composed of microstructured optical fibers for wide visible-to-infrared and refractive index ranges

ObjectiveOptical fiber sensing technology develops rapidly and is widely used. In order to design a SPR sensor with better performance and easy production, a new type D-MOF sensor with low loss, high sensitivity and simple structure is proposed. MethodsThe full vector finite element method (FEM) was used to optimize the structure parameters by using the multi-physics analysis software COMSOL, and the performance of the structure was systematically analyzed. ResultsThe sensor operational wavelength spans the visible and infrared range (430 nm to 7200 nm). The refractive index detection range of 1.00–1.42, the maximum wavelength sensitivity and the optimal resolution are 60,000 nm/RIU and 1.67 × 10−6 RIU−1, respectively, and the maximum limiting loss peak is 64.99 dB/cm. In addition, MOF-SPR sensors have large tolerance and low sensitivity of structural parameters in actual manufacturing. It has great application potential in biosensing and other fields.

A highly sensitive six-conjoined-tube anti-resonance optical fiber temperature sensor based on surface plasmon resonance

ObjectOwing to advances in optical fiber sensing, sensing techniques based on surface plasmon resonance (SPR) have received much attention. In this work, an SPR temperature sensor based on the anti-resonant fiber (ARF) is designed and analyzed. By filling the core with a thermosensitive liquid, the ambient temperature in the range of 5–55 °C can be detected. MethodsThe proposed ARF was simulated utilizing the finite element analysis software COMSOL, followed by systematic and comprehensive structural parameter optimization, and the basic characteristics of the ARF-SPR temperature sensor were analyzed. Filling with a gold medium instead of the traditional coating process reduces the difficulty in manufacturing the ARF-SPR temperature sensor. ResultsThe average temperature sensitivity of the ARF-SPR sensor is 16.055 nm/°C, the minimum structural parameter sensitivity is 1.0 nm/μm, and the maximum FOM is 360.8 °C−1 at 5 °C. The ARF sensor with excellent properties has large commercial potential in biochemical analysis, temperature monitoring, as well as long-distance sensing.

Orbital angular momentum-excited surface plasmon resonance for liquid refractive index sensing by photonic crystal fiber with high sensitivity and wide detection range

With the continuous development of optical fiber sensing technology, the photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) excited by the LP0,1 mode has attracted extensive attention. In this work, an SPR PCF excited by the HE1,1 mode is designed and the various structural parameters are optimized from the perspective of the wavelength sensitivity. The phase matching, mode field distribution, wavelength sensitivity, amplitude sensitivity, structural parameter sensitivity, and figure of merit (FOM) of the PCF-SPR sensor are systematically and comprehensively analyzed numerical by the finite element method and the characteristics are compared to those of representative PCF sensors reported in recent years. The highest wavelength sensitivity of the PCF-SPR sensor is 25,800 nm / RIU, resolution is 3.87 × 10 − 6 RIU, and FOM is 289.83 RIU − 1. The excellent sensing properties suggest that the sensor has immense potential in petroleum logging, geological exploration, and other applications.

Double-formant surface plasmon resonance for refractive index sensing by anti-resonance fibers with high sensitivity and wide detection range

Owing to advances in the surface plasmon resonance (SPR) technology, sensors composed of photonic crystal fibers (PCFs) based on SPR have attracted extensive attention. Herein, a double-formant SPR refractive index sensor comprising the anti-resonant fiber (ARF) is designed and analyzed, which can be used to realized high sensitivity and wide detection range. SPR is excited by gold filling in the negative curvature tube and replaces the traditional coating process to reduce the difficulty associated with actual production. Finite element analysis indicates that the optimized ARF-SPR sensor can detect analytes in the refractive index range of 1.310–1.445 with a maximum wavelength sensitivity and amplitude sensitivity of 36400 nm/RIU and 2,573.33 RIU−1, respectively. In addition, the minimum resolution and structural parameter sensitivity is 2.747 × 10-6 RIU and 38 nm/μm. The maximum figure of merit (FOM) is 776.15 RIU−1, and as the refractive index of the analyte increases, the length of the sensor decreases, which suggesting great potential in biochemical detection and geological exploration.

HE1,1 mode-excited surface plasmon resonance for refractive index sensing by photonic crystal fibers with high sensitivity and long detection distance

ObjectiveAs a result of the rapid development of optical fiber sensing technology, photonic crystal fiber (PCF) sensors based on surface plasmon resonance (SPR) have attracted extensive attention. To design SPR sensor with better performance, a novel ring-core PCF sensor excited by the HE1,1 mode is proposed and demonstrated. MethodsBy means of finite element method (FEM) simulation, the structure is optimized and the properties are analyzed systematically with the multi physical field analysis software COMSOL. ResultsThe sensor can detect analytes with refractive indexes in the range between 1.34 and 1.425 with average sensitivity and resolution of 13,541.18 nm/RIU and 7.38 × 10−6 RIU respectively, the longest detection distance is 556.59 m. In addition, PCF-SPR sensor has large tolerance in actual manufacturing with the low sensitivity of structural parameters and the amplitude sensitivity of all analytes is above 80 RIU−1. This high-performance sensor has large application potential in biological sensing and oil logging.

Wear Analysis of Support Spring of Sprag Clutch during State of Overrunning

This paper analyzes the wear of the support spring of sprag clutches for different structural parameters during overrunning state. Specifically, the stiffness model of the support spring is established based on the characteristics of the variable helix angle, and also the supporting force model is established according to the energy conservation law during the working process of the sprag clutch. Meanwhile, the relative rotation speed between the support spring and the wedge is analyzed by dynamic simulation method. Furthermore, the wear model of the support spring in process of overrunning is established based on Archard wear theory. The results show that there is a linear relationship between supporting force and spring radial displacement compression. In addition, increasing free length and wire diameter of springs will aggravate the wear of springs, whereas enlarging pitch diameter of springs will reduce it. When free length is increased from 270 to 290 mm, the wear time is reduced by 20.88%; when wire diameter is increased from 0.5 to 0.7 mm, the wear time is reduced by 42.75%; when pitch diameter is increased from 2 to 2.4 mm, the wear time is increased by 3.35%. The degree of influence of the structural parameters on the spring wear from large to small is free length, wire diameter, and pitch diameter. Exactly speaking, when wear time is 100 hr, the relative sensitivity of structural parameters affecting the wear of the support spring is in order of free length (2.2), wire diameter (0.97), and pitch diameter (0.08). The research provides a reference for the design and optimization of the support spring for highly reliable sprag clutches.

Experimental and CFD study on the optimization of valve lintel’s structural parameters under critical self-aerated conditions

Self-aerated technology of valve lintel (SATVL) is widely used in high head navigation lock water delivery system to address the cavitation problem. To optimize the structural parameters of valve intel including the height of the throat () and divergent part enhance (), the length of the throat part () and the divergent part (), and the diffusion angle () for better self-aerated performance, the dimensionless structural parameters and beta were chosen as the variables. The conception of critical self-aerated conditions was proposed via theoretical analysis and experimental verification for the first time, and the slope m of critical self-aerated conditions was taken as the response to assess self-aerated performance. The method of combing Response Surface Methodology (RSM) with Central Composite Design (CCD) was introduced to systematically investigate the effects of the structural parameters on the self-aerated performance. A 1: 1 full-scale slicing physical model and CFD simulations were designed to capture the critical self-aerated conditions. Finally, though multiple regression analysis, a quadratic polynomial equation between m and structural parameters was obtained. It was found that: (i) the results of theoretical analysis and physical model verification confirmed the hypothesis of critical self-aerated conditions. (ii) with the aid of ANOVA, the sensitivity of structural parameters which influenced critical self-aerated conditions is . (iii) the optimal structural parameters are and . The result indicate that the substantial improvement of self-aerated performance can be achieve by using those optimal structural parameters.

Experimental investigations on atomization characteristics of dual-orifice atomizers part I: Optimization method formation

In this paper, influences of structure parameters on mass flow and atomization characteristics (spray cone angle, SMD, liquid film fusion and separation) of dual-orifice atomizers were investigated using Fraunhofer diffraction optical instrument and high-speed shadowgraph technique. The main influential structure parameters are obtained by structural parameter sensitivity analysis. Liquid film fusion and separation is an important atomization characteristic lacking of in-depth research. Results of liquid film fusion and separation illustrate that three patterns (separation-fusion-secondary separation) of main stage liquid film and pilot stage liquid film appear with the increase of Δ P. Liquid film fusion makes SMD larger, and there is a delay in liquid film separation when reduce Δ P after liquid film fusion. In addition, mass flow and spray cone angle are key factors which affect liquid film fusion pressure, liquid film secondary separation pressure and distance between two liquid films. The smaller the pilot stage mass flow is, the larger the effect of the main stage on pilot stage spray cone angle will be. Results in this paper could be used to the design and optimization of new dual-orifice atomizers.

Analysis and design of coaxial nozzle with rectangular outlet for high power diode laser in laser metal deposition

High power diode laser (HPDL) characterized by a wider rectangle beam spot (RBS) with top-hat intensity distribution is particularly applied in laser metal deposition to manufacture large-scale components. In order to design a coaxial nozzle with rectangular outlet to match the RBS of the HPDL, a novel wide-beam coaxial feeding nozzle (WBCFN) outlet is proposed. Based on the gas-powder flow model established in ANSYS FLUENT, the influence of structural parameters of the new coaxial nozzle on the gas flow and powder distribution is investigated. Two quantitative indexes are defined to seek out the optimal designing scheme that minimize the divergences of the powder flow and uniform the powder distribution in transverse and longitudinal directions. And then, the effect and sensitivity of structural parameters on concentration distribution and focal length of powder flow are analyzed. The results indicate that the two indexes increase with the increase of exit width, while the variance of concentration firstly increases and then decreases with the increase of the chamber length and inclination angle. The focal length decreases with the increase of inclination angle. Finally, the optimal solution of designing scheme is obtained through comprehensive analysis, and experiments are carried out to validate the model, which indicates that the designed WBCFN can acquire good morphology and quality of deposition layer for HPDL.

Sensitivity analysis of mesoscale structural parameters for simulation of fluidized beds

This study presents new numerical drag models with which to analyze the sensitivity of mesoscale structural parameters in bubbling, turbulent, and circulating fluidized beds. The drag models are derived using the method of transfer-coefficient-based structural parameters (TC-SP). Analyzing the sensitivity of the structural parameters reveals that the coefficients associated with drag are more sensitive to parameters in the dense phase than to those in the dilute phase, especially the superficial slip velocity. On the basis of these results, the TC-SP drag model is simplified further. Interestingly, despite having half the number of parameters of conventional structure-based drag models, the simplified TC-SP drag model achieves simulation results that are equally or more accurate. With simple calculations and improved accuracy using coarse grids, the model reported in this study is capable of predicting the hydrodynamics of the three types of fluidized beds.

Structural Parameter Sensitivity Analysis of an Aircraft Anti-Icing Cavity Based on Thermal Efficiency

The objective of this paper is to accurately describe the influence of structural parameter uncertainties on the thermal efficiency of an aircraft wing anti-icing cavity. To do this, a new method of parameter sensitivity evaluation is proposed according to the weighted stochastic response surface method. First, the concept of fitting the explicit performance function of the anti-icing cavity structure using the weighted stochastic response surface method is presented. A structural parameter sensitivity analysis based on thermal efficiency is then conducted considering the uncertainties of the position of the flute tube, the height of the double-skin channel, and the diameter and angle of the jet holes. The results indicate that the height of the double-skin channel and the diameter of the jet holes are the main factors influencing the functional reliability of the anti-icing cavity.

Optimization of Sound Transmission Loss Characteristics of Orthogonally Stiffened Plate

An analytical model is developed to investigate the sound transmission loss from orthogonally rib-stiffened plate structure under diffuse acoustic field excitation. The validity and feasibility of the model are verified by comparing the present theoretical predictions with the numerical results published previously. The influences of structure geometrical parameters on sound transmission loss are subsequently presented. The optimization algorithm is used to search for the optimal structural parameters with the objective to maximize the sound transmission loss over a frequency band. Furthermore, the sensitivity of structural parameters on the overall vibration and acoustic performance of the stiffened plates structure is also analyzed.

Optimization of Sound Transmission Loss Characteristics of Orthogonally Stiffened Plate

An analytical model is developed to investigate the sound transmission loss from orthogonally rib-stiffened plate structure under diffuse acoustic field excitation. The validity and feasibility of the model are verified by comparing the present theoretical predictions with the numerical results published previously. The influences of structure geometrical parameters on sound transmission loss are subsequently presented. The optimization algorithm is used to search for the optimal structural parameters with the objective to maximize the sound transmission loss over a frequency band. Furthermore, the sensitivity of structural parameters on the overall vibration and acoustic performance of the stiffened plates structure is also analyzed.

Seismic Fragility Analysis of an Isolated Continuous Girder Bridge Using the Response Surface Method with Random Factors

To improve the efficiency of seismic fragility analysis, this paper analyzes the seismic fragility of isolated continuous girder bridges by adopting the response surface method with random factors. A three-dimensional finite element model is established for a typical RC isolated continuous girder bridge in western China using the finite element analysis software OpenSees. Next, test samples are determined according to experimental design theory by simultaneously accounting for the uncertainty of the structure itself and the earthquake ground motion. The response surface models of the scenario's structural capability can be obtained in terms of the numerical calculation results, after which structural parameter sensitivity analysis is conducted. On this basis, a seismic fragility curve for the major components and structural system can be obtained by the Latin Hypercube method. The analysis shows that concrete's compressive strength is the dominant factor affecting structural capacity in the parameter sensitivity analysis. Use of isolation bearing greatly reduces the possibility of pier damage by contrasting the seismic fragility curve. Briefly, the application of this method not only decreases the workload immensely, providing a new idea for seismic fragility analysis, but also has significant, practical value for the design and optimization of similar isolated bridges.

The Effects of Structural Parameter Variation on Cable Force of Fast Cable-Net Structure

Five-hundred-meter aperture spherical radio telescope (FAST) is supported by a cable-net structure, which enables its surface to form a real-time paraboloid by active control. FAST project is currently in the construction and implementation stage. However, there are always a considerable amount of errors that existed in practice which may result in the deviation of the structure from its ideal model or design. Therefore, structural parameter sensitivity analysis was discussed, which is indispensable. However, such deformation operation would lead to about 500 MPa of fatigue stress variation amplitude in the cable-net structure. Optimized deformation strategy is proposed to release the fatigue stress of the cable-net structure, which would be of advantage to improve the reliability of the cable-net structure. In the paper, the variation ranges of structural parameters were rationally determined. Based on local sensitivity analysis and global sensitivity analysis method, finite element model was used to study the effect of different structural parameters on the static behavior. It can be concluded that the effect of several key design parameters such as the cutting length and the elastic modulus of cable on the cable force is significant. The global sensitivity analysis indicates that the cable force range of the cable-net is −19% to 27%.

Parameter Sensitivity and Reliability Analysis for Construction Control of Cable-Net Structure Supporting the Reflector of FAST

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is supported by cable-net structure, which enables its surface to form a paraboloid in real time under active control. FAST is now entering project construction and implement stage, however there are always a considerable amount of errors existed in practice which would result in the deviation of the structure from its ideal model. Therefore, structural parameter sensitivity analysis was indispensable discussed. In the paper, the variation ranges of structural parameters were rationally determined. Base on local sensitivity analysis and global sensitivity analysis method, Using the finite element model investigated the influence of different structural parameters change on the static behavior, gets the conclusions that the impact of several key design parameters on the tension force of cable-net is large. The results indicate that of all types of the structural parameters, the error of the length of cable plays the most important role, and the global sensitivity analysis indicates that the tension force range of cable-net is -18% to 27%.

Optimization Design of Vehicle Front Suspension Structure Parameters Using DOE Method

Based on Multi-body system Dynamic theory, front suspension model is established by using ADAMS/Car, and then the validation is finished according to suspension K&C test project. Through the model simulation, the sensitivity of structure parameters to suspension kinematics characteristics has been analyzed and then the most sensnetive ones have been sorted out. The suspension structure geometry parameters are optimized by the application of DOE method based on virtual prototype technology. The parallel travel simulation results are as follows: the values of camber angle, toe angle, kingpin inclination angle, steer angle and lift/dive are reduced, and the values of caster angle are increased slightly with the optimized suspension. Consequently, the optimized suspension is more conducive to vehicle handling stability compared with the original one. This optimization design method provides the technical support for suspension positive development.

Parameter and Structural Sensitivity of Econometric Models

Sensitivity analysis which can be used as an evaluation technique for mathematical models, is discussed in relation to an econometric model. Parameter sensitivity functions are used to define a performance criterion by which a comparison may be made of the simulation properties of the econometric model for different estimation methods. Structural parameter sensitivity functions are introduced to evaluate the way in which various variables are used in the structure of an econometric model. The simple KLEIN 1 model is used as an example for the analysis, but the sensitivity methods discussed in the paper can easily be extended to accommodate more complicated macroeconometric models containing intricate lag patterns and non-1inearities.