Journal articles: 'Multi-input loading'

1

Zhi, Hao, and Jiahao Lin. "Random loading identification of multi-input-multi-output structure." Structural Engineering and Mechanics 10, no. 4 (October 25, 2000): 359–69. http://dx.doi.org/10.12989/sem.2000.10.4.359.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Wang, J., S. Jiang, J. He, and Z. Liu. "Adaptive detectors with diagonal loading for airborne multi-input multi-output radar." IET Radar, Sonar & Navigation 3, no. 5 (2009): 493. http://dx.doi.org/10.1049/iet-rsn.2008.0128.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Baroux, Emilien, Benoit Delattre, Andrei Constantinescu, Patrick Pamphile, and Ida Raoult. "Analysis Of Real-Life Multi-Input Loading Histories For The Reliable Design Of Vehicle Chassis." Procedia Structural Integrity 38 (2022): 497–506. http://dx.doi.org/10.1016/j.prostr.2022.03.050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Kuriki, M., S. Kuroguchi, H. Tajino, T. Takahashi, Z. Liptak, T. Omori, J. Urakawa, and K. Yokoya. "Beam Loading Compensation of Traveling Wave Linac to a Multi-bunch Pulse with Gaps." Journal of Physics: Conference Series 2687, no. 2 (January 1, 2024): 022012. http://dx.doi.org/10.1088/1742-6596/2687/2/022012.

Full text

Abstract:

Abstract In the electron driven ILC (International Linear Collider) positron source, the beam is generated and accelerated in a multi-bunch format with mini-trains. The macro-pulse contains 2 to 4 mini-trains with several gaps, because the pulse format is a copy of a part of the bunch storage pattern in DR (Damping Ring). This pulse format causes a variation of the accelerator field in the pulse due to the transient beam loading and an intensity fluctuation of captured positron. The beam loading is compensated by amplitude modulation on the input RF in the positron booster composed from L-band and S-band traveling wave RF cavity. In this article, we derive the exact solution for the compensation with the gaps. In addition, we evaluate the effect of the time constant (delay) of the input RF modulation due to klystron Q-value.

APA, Harvard, Vancouver, ISO, and other styles

5

Tang, Enling, Li Wang, Ruizhi Wang, Yafei Han, Xiaochu Lin, Guowen Gao, Liping He, Shenghai Xiang, and Meng Wang. "Influence of the Storage Energy Capacitance on Their Electrical Output Characteristics of Piezoelectric Ceramic during the Process of High-Velocity Impact." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 36, no. 5 (October 2018): 949–54. http://dx.doi.org/10.1051/jnwpu/20183650949.

Full text

Abstract:

In order to reveal influence of external capacitance on the voltage input and input energy provided by the PZT-5H piezoelectric ceramic composite structure under high-speed impact loading, experiments have been performed by using one-stage light gas gun loading system combining with a power supplier circuit and power output testing system, which the aspect ratio of 1:1 column projectile impact monolithic and multi-piece piezoelectric ceramic composite structure at the near impact velocity and different storage capacity. The experimental results show that the more larger storage capacitance is, the smaller the piezoelectric ceramic output voltage is. However, the smaller of the capacitor voltage is, the smaller the value of energy storage is; with the energy storage capacitance increasing, the piezoelectric capacitance ratio and the energy conversion rate of piezoelectric ceramics decreases; In addition, the storage energy capacitor increases with the increasing of the piezoelectric ceramic layers; the relationships of storage energy capacitor and piezoelectric ceramic capacitor has a great influence on the input voltage and storage energy for storage energy capacitor.

APA, Harvard, Vancouver, ISO, and other styles

6

Zhang, Lin, Cheng-ge Wu, and Gan-wei Cai. "The inverse kinematics analysis and simulation study on the controllable loading mechanism." MATEC Web of Conferences 189 (2018): 06011. http://dx.doi.org/10.1051/matecconf/201818906011.

Full text

Abstract:

The multi-DOF controllable loading mechanism adopts the electric drive system to replace the hydraulic drive system of traditional loader, not only has higher transmission efficiency and has better mechanical and electrical integration level, but also overcome the shortcomings of high cost of manufacture and maintenance.The inverse kinematics model of this type of loading mechanism was built by means of closed loop vector method. According to the performance index of the loading mechanism, the inverse kinematics model was solved by means of MATLAB software, and the input motion law of the two driving lever at different period of time is obtained, and a small prototype is built, which provides the basis for control system programming of this new type of leading mechanism. To some extent, this research lays a foundation for further development of this type of loading mechanism.

APA, Harvard, Vancouver, ISO, and other styles

7

Chen, Mu-Chun, Tsung-Wen Sun, and Tsung-Heng Tsai. "Dual-Domain Maximum Power Tracking for Multi-Input RF Energy Harvesting with a Reconfigurable Rectifier Array." Energies 15, no. 6 (March 11, 2022): 2068. http://dx.doi.org/10.3390/en15062068.

Full text

Abstract:

This work proposes a dual-domain maximum power tracking (MPPT) technique for multiple-input RF energy harvesting systems. A differential rectifier array is used to implement 4-channel reconfigurable RF to DC power conversion, and an adjustable 4-bit capacitor array is designed to improve the impedance matching between the antennas and the rectifiers. Using the perturbation and observation (P&O) method, both arrays are adaptively configured in the background with the variations of the input energy and output loading. Experimental results show that the proposed circuit successfully tracks the maximum power points while harvesting RF energy, with the peak conversion efficiency of 49.06% when the input energy is −6 dBm. With the proposed dual-domain MPPT, the high efficiency range of the energy harvesting system is greatly extended to 21 dB (−21–0 dBm).

APA, Harvard, Vancouver, ISO, and other styles

8

Kushvaha, Vinod, S. Anand Kumar, Priyanka Madhushri, and Aanchna Sharma. "Artificial neural network technique to predict dynamic fracture of particulate composite." Journal of Composite Materials 54, no. 22 (March 8, 2020): 3099–108. http://dx.doi.org/10.1177/0021998320911418.

Full text

Abstract:

In this paper, the artificial neural network technique using a multi-layer perceptron feed forward scheme was used to model and predict the mode-I fracture behaviour of particulate polymer composites when subjected to impact loading. A neural network consisting of three-layers was employed to develop the network. Artificial neural network was constructed using six input parameters such as shear wave speed ( CS), density ( D), elastic modulus ( Ed), longitudinal wave speed ( CL), volume fraction ( Vf) and time ( t). The influence of input parameters on the output stress intensity factor and crack-initiation fracture toughness were found to be in the order of t > CS > D > Ed > CL > Vf. The degree of accuracy of prediction was 92.7% for stress intensity factor. In this regard, artificial neural network can be used in the modelling and prediction of fracture behaviour of particulate polymer composites under impact loading.

APA, Harvard, Vancouver, ISO, and other styles

9

Kuriki, M., S. Konno, H. Tajino, Z. Liptak, T. Takahashi, M. Fukuda, T. Omori, et al. "Beam loading compensation of standing wave linac with off-crest acceleration." Journal of Physics: Conference Series 2420, no. 1 (January 1, 2023): 012007. http://dx.doi.org/10.1088/1742-6596/2420/1/012007.

Full text

Abstract:

Abstract In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.

APA, Harvard, Vancouver, ISO, and other styles

10

Koofigar, Hamid Reza, and Ghader Isazadeh. "Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay." Archives of Electrical Engineering 66, no. 3 (September 1, 2017): 459–74. http://dx.doi.org/10.1515/aee-2017-0034.

Full text

Abstract:

AbstractA robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC). The mixedH2/H∞problem with regional pole placement, resolved by linear matrix inequality (LMI), is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multi-machine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

APA, Harvard, Vancouver, ISO, and other styles

11

Frecker, M. I., G. K. Ananthasuresh, S. Nishiwaki, N. Kikuchi, and S. Kota. "Topological Synthesis of Compliant Mechanisms Using Multi-Criteria Optimization." Journal of Mechanical Design 119, no. 2 (June 1, 1997): 238–45. http://dx.doi.org/10.1115/1.2826242.

Full text

Abstract:

Compliant mechanisms are mechanical devices that achieve motion via elastic deformation. A new method for topological synthesis of single-piece compliant mechanisms is presented, using a “design for required deflection” approach. A simple beam example is used to illustrate this concept and to provide the motivation for a new multi-criteria approach for compliant mechanism design. This new approach handles motion and loading requirements simultaneously for a given set of input force and output deflection specifications. Both a truss ground structure and a two-dimensional continuum are used in the implementation which is illustrated with design examples.

APA, Harvard, Vancouver, ISO, and other styles

12

Sous, Christopher, Henrik Wünsch, Georg Jacobs, and Christoph Broeckmann. "Prediction of fatigue limit of journal bearings considering a multi-axial stress state." Industrial Lubrication and Tribology 68, no. 3 (April 11, 2016): 430–38. http://dx.doi.org/10.1108/ilt-08-2015-0119.

Full text

Abstract:

Purpose The purpose of this paper is to investigate the applicability of the quadratic failure hypothesis (QFH) on journal bearings coated with a white metal sliding layer on the prediction of safe and unsafe operating conditions. The hypothesis covers operation conditions under static and dynamical loading. Design/methodology/approach Material tests and elastohydrodynamic, as well as structural, simulations were conducted to provide the required input data for the failure hypothesis. Component samples were tested to verify the results of the QFH. Findings The load bearing capacity of journal bearings was analysed for different operating conditions by the use of the QFH. Results allow for the identification of critical and non-critical loading conditions and are in accordance with component test results. Originality/value Today’s design guidelines for journal bearings do not consider a multi-axial stress state and actual stress distribution. The applied hypothesis enables consideration of multiaxiality inside the sliding surface layer, as well as determining the location of bearing fatigue due to material overload.

APA, Harvard, Vancouver, ISO, and other styles

13

Hauptman, S., A. Volte, G. Kohse, M. Carette, A. Lyoussi, and C. Reynard-Carette. "Flux and Nuclear Heating Rate Calculations for CALORRE Irradiation in MITR." EPJ Web of Conferences 288 (2023): 04010. http://dx.doi.org/10.1051/epjconf/202328804010.

Full text

Abstract:

This work summarizes neutronic calculations performed for the CALORRE differential calorimeter specifically designed by Aix Marseille University to inform the irradiation campaign planning for testing in MITR within the framework of the CALOR-I research program. MCNP software was used to predict the neutron and gamma flux spectrum, and total nuclear heating rate to the components of the calorimeter in a variety of positions. Results were compared to evaluate spatial bias, core loading effects, optimization for axial position, and provide input data for thermal multi-physics modelling.

APA, Harvard, Vancouver, ISO, and other styles

14

Hong, Hong-Ki, Li-Wei Liu, Ya-Po Shiao, and Cheng-Jih Chang. "Building structure with elastoplastic bilinear model under multi-dimensional earthquake forces." Journal of Mechanics 38 (2022): 598–609. http://dx.doi.org/10.1093/jom/ufac045.

Full text

Abstract:

Abstract Developed herein is an analysis procedure based on closed-form solutions to elastoplastic bilinear model of building structures accounted for different stiffnesses and yielding forces in different directions and rotated yield ellipses in different floor levels due to the layout of buildings and the complexity of structural members. The seismic design often considers earthquake forces on multiple floor levels but usually only in a single direction. However, in reality, the direction of the earthquake is not limited to one particular direction. Therefore, studying the influence of a two-way, furthermore multi-dimensional, earthquake on buildings is of great value. To estimate the total seismic demand on inelastic building structures subjected to multi-dimensional loading, this paper aims to find closed-form solution responses to an input rectilinear force path for the elastoplastic bilinear model of Hong and Liu (1999) which already has available closed-form solution responses to an input rectilinear displacement path. In this paper the elastoplastic bilinear model of building structures and Minkowski spacetime are adapted to accommodate such situations as different stiffnesses and yielding forces in different directions and rotated yield ellipses in different floor levels.

APA, Harvard, Vancouver, ISO, and other styles

15

Bora, P., P. Pokkunuri, and B. T. P. Madhav. "The Design of Closed Square RR Loaded 2-Port MIMO for Dual Band Applications." Engineering, Technology & Applied Science Research 12, no. 2 (April 9, 2022): 8382–87. http://dx.doi.org/10.48084/etasr.4760.

Full text

Abstract:

In this paper, a closed square ring resonator loaded 2-port Multi Input Multi Output (MIMO) is proposed for dual-band applications in the S and C band. The presented antenna model is designed by loading it in FR-4 substrate with a feedline of 50Ω and loaded with SRR for the enhancement of isolation and radiation pattern. Ansoft HFSS is used to obtain the simulated parameters of the model for the frequency ranges of 2.2-2.5 and 6-6.3GHz. Measurements confirm the characteristics of the fabricated antenna that were speculated with the simulation results with a little shift in frequencies. The diversity parameter performance analysis justifies the working performance of the 2-port MIMO for WiFi, WLAN, and ISM band applications.

APA, Harvard, Vancouver, ISO, and other styles

16

Sun, Q., X. R. Liu, and K. Liang. "Impact Fatigue Life Prediction for Notched Specimen of Steel AerMet100 Subjected to High Strain Rate Loading." International Journal of Applied Mechanics 10, no. 03 (April 2018): 1850030. http://dx.doi.org/10.1142/s1758825118500308.

Full text

Abstract:

In this study, the ultra-low cycle fatigue (ULCF) behavior of a high-strength-ductile steel AerMet100 exposed to repeated high strain rate impact loadings is investigated. Three types of coupon-level experiments were performed, in which a three-point bending (TPB) specimen with a through-thickness notch was employed for multi-impact test. A special ratchet effect associated with complex stress state, dynamic impact loading and other physical mechanisms was observed through measured principal strain variations with a specific decay rate at the notch root surface. An improved ULCF predictive model based on the continuum damage mechanics was developed to quantify the relationship between the fatigue damage and the input of localized impact energy to the notch root. The model expressed in terms of damage growth rate introduces a new exponential term for better predictive accuracy and reduced number of nonlinear dynamic response analysis. As a computational efficient tool, the proposed model can predict impact fatigue life in acceptable timeframe for multiple critical locations in a complex engineering component.

APA, Harvard, Vancouver, ISO, and other styles

17

Ramly, Ramzyzan, Wahyu Kuntjoro, Amir Radzi Abdul Ghani, Rizal Effendy Mohd Nasir, and Zulkifli Muhammad. "Multi-configuration Stiffened Panels under Compressive Load: Part 1 – Theoretical Analysis." International Journal of Engineering & Technology 7, no. 3.11 (July 21, 2018): 38. http://dx.doi.org/10.14419/ijet.v7i3.11.15926.

Full text

Abstract:

Stiffened panels are the structure used in the aircraft wing skin panels. Stiffened panels are often critical in compression load due to its thin structural configuration. This paper analyzes the critical loads of a multi configuration stiffened panels under axial compressive loading. The study comprised three main sections; theoretical analysis, numerical analysis and experimental analysis. The present paper deals only with the theoretical analysis. This first part of analysis is very important since the results will be the main input parameter for the subsequent numerical and experimental analysis. The analysis was done on the buckling properties of the panels. Four panel configurations were investigated. Results showed that even though the stiffened panels have the same cross-sectional area, their critical loads were not identical.

APA, Harvard, Vancouver, ISO, and other styles

18

Gopalakrishnan, Kasthurirangan, and Siddhartha Kumar Khaitan. "FINITE ELEMENT BASED ADAPTIVE NEURO‐FUZZY INFERENCE TECHNIQUE FOR PARAMETER IDENTIFICATION OF MULTI‐LAYERED TRANSPORTATION STRUCTURES." TRANSPORT 25, no. 1 (March 31, 2010): 58–65. http://dx.doi.org/10.3846/transport.2010.08.

Full text

Abstract:

During the service life of a pavement, it is often required to conduct Non-destructive tests (NDTs) to evaluate its structural condition and bearing capacity and to detect damage resulting from the repeated traffic and environmental loading. Among several currently used NDT methods, the Falling Weight Deflectometer (FWD) is the most commonly used pavement NDT method applied by many transportation agencies all over the world. Non-destructive testing of pavements using FWD is typically accompanied by the prediction of the Young’s modulus of each layer of the pavement structure through an inverse analysis of the acquired FWD deflection data. The predicted pavement layer modulus is both an indicator of the structural condition of the layer as well as a required input for conducting mechanistic-based pavement structural analysis and design. Numerous methodologies have been proposed for backcalculating the mechanical properties of pavement structures from NDT data. This paper discusses the development of an Adaptive-Network-based Fuzzy Inference System (ANFIS) combined with Finite Element Modeling (FEM) for the inverse analysis of the multi-layered flexible pavement structures subjected to dynamic loading.

APA, Harvard, Vancouver, ISO, and other styles

19

Ma, Hao, Wei Wei Wang, and Jing Bo Yu. "Design of the Parametric Simulation Program for Multi-Point Forming Based on APDL." Advanced Materials Research 148-149 (October 2010): 763–68. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.763.

Full text

Abstract:

Two difficulties exist in the finite element analysis of multi-point forming: the complicated modeling process and the difficulty to control the movement pattern of more punches simultaneously. In the present paper, the design process of parametric simulation program for multi-point die forming and force-displacement separated control forming by using ANSYS parametric design language (APDL) is described. The rapid modeling is realized by use of the parameter input dialog box. The calculation program for the original position of each punch is designed, and then the stroke of each punch is determined. The process of model definition, loading and analysis is controlled by customized multi-point forming toolbar. The parametric finite element analysis process for spherical surface forming with the force-displacement separated control forming method is described in the paper. The results indicate that the simulation requirements for different parameters and different forming modes can be satisfied by the designed parametric simulation program.

APA, Harvard, Vancouver, ISO, and other styles

20

Wibowo, Wahyu, Taly Purwa, Brodjol Sutijo Suprih Ulama, and Regina Niken Wilantari. "Investigating the effects of several intervention on supply chain behavior: Evidence from West Nusa Tenggara Province, Indonesia." Uncertain Supply Chain Management 10, no. 2 (2022): 601–24. http://dx.doi.org/10.5267/j.uscm.2021.11.004.

Full text

Abstract:

This study analyzed the impact magnitudes and patterns of several intervention events, including eight earthquakes and Covid-19 pandemic, on the number of unloading and loading goods in the three main ports and airports in West Nusa Tenggara Province during 2015-2020. The multi-input intervention models are performed for twelve series data obtained from BPS-Statistics of West Nusa Tenggara Province. The results from the estimated response values show that generally the number of unloading and loading in the three main ports and airports have experienced mixed impact, i.e., negative, and positive impacts. As the main concern in this study, the negative impacts were more experienced by the number of unloading and loading goods in airports than in ports indicating that the supply chain in airports was more vulnerable to intervention. Lombok International Airport and Sultan M Kaharuddin Airport received the most negative impact during the period. Most intervention events have delayed impact patterns that are more experienced by the three airports than the three ports. Started in March 2020, Covid-19 produced the widest and biggest negative impacts. These impacts are even bigger than the impacts produced by the severe earthquakes that occurred in August 2018.

APA, Harvard, Vancouver, ISO, and other styles

21

Venkatesan, Hariram, John Johnrose, Saravanan Arumugam, Kumar Mari, Balachandar Moorthy, Samuel Stalin, Seralathan Sivamani, and Lakshmi Vasudev. "Optimized biodiesel production from C. innophyllum bio-oil using Kriging and Ann predicitive models." Thermal Science, no. 00 (2022): 32. http://dx.doi.org/10.2298/tsci211127032v.

Full text

Abstract:

This work aimed at optimizing the two-stage transesterification efficiency of the production of Calophyllum inophyllum biodiesel using Artificial Neural Network and Kriging predictive models. Response Surface Methodology was used to develop the central rotatable composite design of twenty-seven trial experimental runs with variations in the input process parameters like methanol to oil molar ratio, potassium hydroxide catalyst loading, and reaction time. A multi-layered non-linear regressive Artificial Neural Network model with feed-forward propagation and a numerical surrogate Kriging model was used to predict the Calophyllum inophyllum biodiesel yield. The efficacy of the developed model was verified using Analysis of Variance by comparing its coefficient of determination and the mean relative percentage deviation values. The optimized Calophyllum inophyllum biodiesel as 98.1% is derived with 0.94 v/v of methanol to oil molar ratio, 0.98 wt % of potassium hydroxide catalyst loading, and 80 minutes reaction time with 70oC constant reaction temperature as predicted by Kriging model. The optimized parameters were also verified experimentally.

APA, Harvard, Vancouver, ISO, and other styles

22

Fan, F., S. Z. Shen, and G. A. R. Parke. "Study of the Dynamic Strength of Reticulated Domes under Severe Earthquake Loading." International Journal of Space Structures 20, no. 4 (December 2005): 235–44. http://dx.doi.org/10.1260/026635105775870251.

Full text

Abstract:

The behaviour of selected steel domes subject to severe earthquake loading has been investigated and reported. Particular attention has been given to assess the development and spread of plasticity throughout these structures. Several dome configurations have been considered, both perfect and imperfect, together with a range of varying rise to span ratios. Finite element analysis of these structures has been undertaken to determine the rate of spread of plasticity and the rate of increase in node displacement under seismic loading. The dynamic strength failure acceleration (DSFA) has been defined as the acceleration at which the rate of spread of plasticity and node displacement reaches a runaway level and the structure becomes dynamically unstable. For the dome structures under consideration DSFA occurred at an acceleration of approximately 8 m/s2. In addition, the DSFA decreased by 15%–50% for the imperfect structures when compared with the perfect domes and was lower for the multi-directional seismic input. Also, the DSFA decreased gradually with a corresponding increase in the rise to span ratio.

APA, Harvard, Vancouver, ISO, and other styles

23

Qian, Zhenyao, Yuan Chen, Chunmei Feng, and Wei Wang. "Compact Multi-Mode Filtering Power Divider with High Selectivity, Improved Stopband and In-band Isolation." Applied Computational Electromagnetics Society 35, no. 8 (October 7, 2020): 936–40. http://dx.doi.org/10.47037/2020.aces.j.350813.

Full text

Abstract:

This letter presents a new compact multi-mode filtering power divider (FPD) design based on co-shared FPD topology with sharp frequency selectivity, improved out-of-band harmonic rejection and port-to-port isolation. Power splitting and quasi-elliptic filtering functions are achieved by masterly integrating only one triple-mode resonator. By loading different open-circuited stubs at the input/output ports, multiple additional transmission zeros (TZs) are generated at both lower and upper stopband, resulting in an improved stopband performance. Meanwhile, a better port-to-port isolation is obtained by adopting frequency-dependent resistor-capacitor parallel isolation network. The proposed multi-mode FPD design stands out from those in the literature by both nice operation performance and compact topology with only one resonator. For demonstration purposes, one triple-mode FPD prototype and its improved one are implemented, respectively. Measured results exhibit the superiority of the FPD design.

APA, Harvard, Vancouver, ISO, and other styles

24

Ghazwan, Aseel, Chris Wilson, Cathy A. Holt, and Gemma M. Whatling. "Knee osteoarthritis alters peri-articular knee muscle strategies during gait." PLOS ONE 17, no. 1 (January 20, 2022): e0262798. http://dx.doi.org/10.1371/journal.pone.0262798.

Full text

Abstract:

The primary role of muscles is to move, and control joints. It is therefore important to understand how degenerative joint disease changes this role with the resulting effect on mechanical joint loading. Muscular control strategies can vary depending on strength and coordination which in turn influences joint control and loading. The purpose of this study was to investigate the variation in neuromuscular control mechanisms and joint biomechanics for three subject groups including those with: uni-compartmental knee osteoarthritis (OA), listed for high tibial osteotomy surgery (pre-HTO, n = 10); multi-compartmental knee OA listed for total knee replacement (pre-TKR, n = 9), and non-pathological knees (NP, n = 11). Lower limb kinematics and electromyography (EMG) data for subjects walking at self-selected speed, were input to an EMG-driven musculoskeletal knee model which was scaled and calibrated to each individual to estimate muscle forces. Compared to NP, the peak gastrocnemius muscle force reduced by 30% and 18% for pre-HTO and pre-TKR respectively, and the peak force estimated for hamstring muscle increased by 25% for pre-HTO. Higher quadriceps and hamstring forces suggest that co-contraction with the gastrocnemius could lead to higher joint contact forces. Combined with the excessive loading due to a high external knee adduction moment this may exacerbate joint destruction. An increased lateral muscle co-contraction reflects the progression from NP to uni-compartmental OA (pre-HTO). Pre-TKR patients adopt a different gait pattern to pre-HTO patients. Increased medial muscle co-activation could potentially differentiate between uni- or multi-compartmental OA.

APA, Harvard, Vancouver, ISO, and other styles

25

Kong, Y. S., Mohd Zaidi Omar, L. B. Chua, and S. Abdullah. "Fatigue Life Prediction of Leaf Spring through Multi Mean S-N Approach." Applied Mechanics and Materials 663 (October 2014): 83–87. http://dx.doi.org/10.4028/www.scientific.net/amm.663.83.

Full text

Abstract:

Parabolic leaf spring is a suspension component for heavy vehicles where spring itself experiences repeated cyclic loading under operating condition. Fatigue life of the parabolic leaf spring is vital since the deflection of the spring is large and continuous. To determine the fatigue life of the parabolic leaf spring, material properties input to the design is important. The objective of this study is to predict the fatigue life of a parabolic leaf spring based on two different material grades which are SAE 5160 and SAE 51B60H under constant amplitude loading through various mean stress method. SAE 51B60H is the material with slightly higher carbon, manganese and chromium content compared to material SAE 5160. Chemical composition differences between SAE 5160 and SAE 51B60H have significant effects on the mechanical properties and fatigue life. In this analysis, finite element method together with multi mean curve stress life (S-N) approach has been implemented to estimate the fatigue life of the spring. Goodman, Gerber and Interpolate mean stress correction method were adopted to correct the damage calculation for mean stress. The results show that interpolate and Goodman method predict the fatigue life of the material with higher accuracy. On the other hand, material SAE 51B60H yields higher fatigue life compared to material SAE 5160.

APA, Harvard, Vancouver, ISO, and other styles

26

Eleftheroglou, N., D. S. Zarouchas, T. H. Loutas, Rene C. Alderliesten, and R. Benedictus. "Online Remaining Fatigue Life Prognosis for Composite Materials Based on Strain Data and Stochastic Modeling." Key Engineering Materials 713 (September 2016): 34–37. http://dx.doi.org/10.4028/www.scientific.net/kem.713.34.

Full text

Abstract:

The present study utilizes a state-of-the-art stochastic modeling with structural health monitoring (SHM) data derived from strain measurements, in order to assess the remaining useful life (RUL) online in composite materials under fatigue loading. Non-Homogenous Hidden Semi Markov model (NHHSMM) is a suitable candidate with a rich mathematical structure capable of describing the composite’s multi-state damage evolution in time. The proposed model uses as input SHM data in the form of strain measurements obtained from the Digital Image Correlation (DIC) technique to a coupon-level constant amplitude fatigue test campaign. The obtained from the stochastic model RUL estimations are compared with the actual RUL and the effectiveness of the prognosis is discussed.

APA, Harvard, Vancouver, ISO, and other styles

27

Shang, Shouping, and Zhen Wang. "Dynamic Analysis of a Spring-Asphalt Three-Dimensional Isolation System Based on Cyclic Simple Shear and Shaking Table Tests." Applied Sciences 10, no. 18 (September 18, 2020): 6530. http://dx.doi.org/10.3390/app10186530.

Full text

Abstract:

Damping is one of the important issues related to isolated structures, including the newly proposed low-cost spring-asphalt isolation system. In this study, the damping properties of the system in terms of displacement dependence, frequency dependence and temperature dependence were studied by a cyclic simple shear experiment. Then, the direct least-square method was used to identify the damping properties from the experimental data. Furthermore, to validate the effectiveness of the damping device, a modal analysis was conducted based on multi-dimensional shaking table tests. The results indicate that (1) the hysteretic curves are similar to an ellipse, which means that the asphalt shows characteristics of viscoelastic materials; (2) the damping properties are positively related to the loading frequency and inversely related to the temperature and displacement; and (3) asphalt can provide adequate damping and reduce the displacements of the superstructure by nearly half. On the basis of the experimental test results, an analysis of the modal information with multi-dimensional input is also presented.

APA, Harvard, Vancouver, ISO, and other styles

28

Lin, Sheng, Jiacheng Wang, Wenkang Xiong, Qingyuan Hu, Hui Liu, and Qi Wang. "Design and Modeling of a Curved Beam Compliant Mechanism with Six Degrees of Freedom." Micromachines 13, no. 2 (January 28, 2022): 208. http://dx.doi.org/10.3390/mi13020208.

Full text

Abstract:

Compliant mechanisms are widely used in cutting-edge scientific and technological fields such as precision engineering, micro-/nano-manipulation, or microelectronics. Hence, the demand for multi-degree-of-freedom compliant mechanisms has increased sharply. The structure of compliant mechanisms becomes increasingly complex with the increase of degrees of freedom. Here, a compliant mechanism with six degrees of freedom is proposed based on curved beams. The compliant mechanism has the advantages of simple structure and multi-degree-of-freedom. Using the isogeometric analysis method, a model of the mechanism is constructed. Static analysis show that six degrees of freedom can be generated. The prototype of the mechanism is developed by 3D printing. A loading test in six degrees of freedom is carried out. The output and input have high linear relations and the structure has low inter-directional coupling. We trust that this study provides a pioneering step towards the design of compliant mechanisms based on curved beam elements.

APA, Harvard, Vancouver, ISO, and other styles

29

Argilaga, Albert, and Efthymios Papachristos. "Bounding the Multi-Scale Domain in Numerical Modelling and Meta-Heuristics Optimization: Application to Poroelastic Media with Damageable Cracks." Materials 14, no. 14 (July 16, 2021): 3974. http://dx.doi.org/10.3390/ma14143974.

Full text

Abstract:

It is very common for natural or synthetic materials to be characterized by a periodic or quasi-periodic micro-structure. This micro-structure, under the different loading conditions may play an important role on the apparent, macroscopic behaviour of the material. Although, fine, detailed information can be implemented at the micro-structure level, it still remains a challenging task to obtain experimental metrics at this scale. In this work, a constitutive law obtained by the asymptotic homogenization of a cracked, damageable, poroelastic medium is first evaluated for multi-scale use. For a given range of micro-scale parameters, due to the complex mechanical behaviour at micro-scale, such multi-scale approaches are needed to describe the (macro) material’s behaviour. To overcome possible limitations regarding input data, meta-heuristics are used to calibrate the micro-scale parameters targeted on a synthetic failure envelope. Results show the validity of the approach to model micro-fractured materials such as coal or crystalline rocks.

APA, Harvard, Vancouver, ISO, and other styles

30

Reggio, Anna, Rita Greco, Giuseppe Carlo Marano, and Giuseppe Andrea Ferro. "Stochastic Multi-objective Optimisation of Exoskeleton Structures." Journal of Optimization Theory and Applications 187, no. 3 (November 18, 2020): 822–41. http://dx.doi.org/10.1007/s10957-020-01778-8.

Full text

Abstract:

AbstractIn this study, a structural optimisation problem, addressed through a stochastic multi-objective approach, is formulated and solved. The problem deals with the optimal design of exoskeleton structures, conceived as vibration control systems under seismic loading. The exoskeleton structure is assumed to be coupled to an existing primary inner structure for seismic retrofit: the aim is to limit the dynamic response of the primary structure to prevent structural damage. A non-stationary filtered Gaussian white noise stochastic process is taken as the seismic input. Design variables pertain to the mechanical properties (stiffness, damping) of the exoskeleton structure. Two concurrent and competing objective functions are introduced, in order to take into account not only safety performance but also economic cost considerations. The resulting trade-off is solved searching the Pareto front by way of a controlled elitist genetic algorithm, derived from the Non-dominated Sorting Genetic Algorithm-II. Sensitivities of Pareto fronts and Pareto optimal sets to different system parameters are finally investigated by way of a numerical application.

APA, Harvard, Vancouver, ISO, and other styles

31

Deng, Shi Gan, Huai Ku Sun, and Chung Jung Chiu. "Nonlinear Transient Finite Element Analysis for Rifle’s Power Transmission Mechanism with Structure Coupling Effects." Applied Mechanics and Materials 764-765 (May 2015): 324–28. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.324.

Full text

Abstract:

This study uses a nonlinear transient finite element method (FEM) to simulate the mechanism and structural behavior of a 5.56 mm rifle’s multi-body power transmission system after being fired. Specifically, this study uses the Vallier-Heydenreich formula to calculate the chamber pressure, and uses the result as the input loading for the FEM model. The analysis in this study considers elastic deformation, joint clearance, and impact effects. The proposed simulation is capable of simultaneously obtaining the kinematic status, transient stresses, and strain history of a rifle. The results of shooting experiments verified the accuracy of the numerical model. The difference in the bolt carrier’s operation cycle between experimental and numerical data was only 1.9%, indicating that this simulation method is credible.

APA, Harvard, Vancouver, ISO, and other styles

32

Čabrilo, Aleksandar, and Nenad Janjić. "WELDING OF HIGH-HARDNESS ARMOR STEEL." Advanced Engineering Letters 1, no. 4 (2022): 148–55. http://dx.doi.org/10.46793/adeletters.2022.1.4.5.

Full text

Abstract:

Armor steels are difficult to weld due to the high percentage of carbon. The coarse-grained area and the fusion line in the welded joint are sensitive areas due to the high hardness and the possible presence of hydrogen produced during the welding process. Furthermore, multi-purpose armored vehicles made of armored steel are exposed to dynamic loading due to traffic on rough terrain. High hardness in the coarse- grained area of the heat-affected zone and dynamic loading can cause cracks. In the weld metal zone, a crack created during the welding process or due to pores can quickly propagate toward the sensitive fusion line, after which its accelerated growth can occur. Based on the above, achieving a welded joint without porosity or cracks for armor steel is necessary. This paper investigated the welding process of high- hardness armor steel with two regimes. The test aims to achieve an optimal hardness level and a compromise between ballistic requirements and toughness. The test results showed that a high-quality welded joint and an optimal balance between hardness and toughness are achieved with increased heat input.

APA, Harvard, Vancouver, ISO, and other styles

33

Громыко, П. Н., С. Н. Хатетовский, В. Л. Юркова, and Д. Ю. Макацария. "ОСНОВНЫЕ ПОКАЗАТЕЛИ ЭКСЦЕНТРИКОВОЙ ПЕРЕДАЧИ С ПАРАЛЛЕЛЬНЫМ РАСПОЛОЖЕНИЕМ ВХОДНОГО И ВЫХОДНОГО ВАЛОВ НА ОСНОВЕ ИСПОЛЬЗОВАНИЯ МНОГОПОТОЧНОЙ СХЕМЫ НАГРУЖЕНИЯ." Vestnik of Brest State Technical University. Civil Engineering and Architecture, no. 2 (128) (July 15, 2022): 75–78. http://dx.doi.org/10.36773/1818-1112-2022-128-2-75-78.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Tonin, Jean Marcel Faria, and Taufik Abrao. "Linear detectors and precoding methods for massive MIMO." Semina: Ciências Exatas e Tecnológicas 42, no. 2 (December 2, 2021): 209. http://dx.doi.org/10.5433/1679-0375.2021v42n2p209.

Full text

Abstract:

Detection in multiple-input-multiple-output (MIMO) wireless communication systems is a crucial procedure in receivers since the multiple access transmission schemes generate interference due to the simultaneous transmission along with the several antennas, unlike single-input-single-output (SISO) transmission schemes. Precoding is a technique in MIMO systems used to mitigate the effects of the channel over the received signal. Hence, it is possible to adjust continuously the transmitted information to reverse the effect of the wireless channel at the receiver side. In this work, linear sub-optimal detectors and precoders for massive MIMO (M-MIMO) systems are implemented, analyzed, and compared in terms of performance-complexity trade-off. It is also being considered numerical results in both channel scenarios: a) receiver and transmitter have perfect channel state information (CSI); b) complex channel coefficients are estimated with different levels of inaccuracy. Monte-Carlo simulations (MCS) reveal that linear zero-forcing (ZF) and minimum mean squared error (MMSE) massive MIMO detectors result in a certain robustness against multi-user interference when operating under low and medium system loading, L = K/M, thanks to the favourable propagation phenomenon arising in massive MIMO systems.

APA, Harvard, Vancouver, ISO, and other styles

35

Simpson, Dakotah J., Roberto Gómez-García, and Dimitra Psychogiou. "Mixed-technology quasi-reflectionless planar filters: bandpass, bandstop, and multi-band designs." International Journal of Microwave and Wireless Technologies 11, no. 5-6 (March 1, 2019): 466–74. http://dx.doi.org/10.1017/s1759078719000230.

Full text

Abstract:

AbstractThe design of mixed-technology quasi-reflectionless planar bandpass filters (BPFs), bandstop filters (BSFs), and multi-band filters is reported. The proposed quasi-reflectionless filter architectures comprise a main filtering section that determines the power transmission response (bandpass, bandstop, or multi-band type) of the overall circuit network and auxiliary sections that absorb the reflected radio-frequency (RF) signal energy. By loading the input and output ports of the main filtering section with auxiliary filtering sections that exhibit a complementary transfer function with regard to the main one, a symmetric quasi-reflectionless behavior can be obtained at both accesses of the overall filter. The operating principles of the proposed filter concept are shown through synthesized first-order BPF and BSF designs. Selectivity-increase techniques are also described. They are based on: (i) cascading in-series multiple first-order stages and (ii) increasing the order of the filtering sections. Moreover, the RF design of quasi-reflectionless multi-band BPFs and BSFs is discussed. A hybrid integration scheme in which microstrip-type and lumped-elements are effectively combined within the filter volume is investigated for size miniaturization purposes. For experimental validation purposes, two quasi-reflectionless BPF prototypes (one- and two-stage architectures) centered at 2 GHz and a second-order BSF prototype centered at 1 GHz were designed, manufactured, and measured.

APA, Harvard, Vancouver, ISO, and other styles

36

Le Corre, Gwenaëlle. "Comparing in-service multi-input loads applied on non-stiff components submitted to vibration fatigue to provide specifications for robust design." MATEC Web of Conferences 165 (2018): 16004. http://dx.doi.org/10.1051/matecconf/201816516004.

Full text

Abstract:

This study focuses on applications from the automotive industry, on mechanical components submitted to vibration loads. On one hand, the characterization of loading for dimensioning new structures in fatigue is enriched and updated by customer data analysis. On the other hand, the loads characterization also aims to provide robust specifications for simulation or physical tests. These specifications are needed early in the project, in order to perform the first durability verification activities. At this time, detailed information about the geometry and the material is rare. Vibration specifications need to be adapted to a calculation time or physical test durations in accordance with the pace imposed by the projects timeframe. In the trucks industry, the dynamic behaviour can vary significantly from one configuration of truck to another, as the trucks architecture impacts the load environment of the components. The vibration specifications need to be robust by taking care of the diversity of vehicles and markets considered in the scope of the projects. For non-stiff structures, the lifetime depends, among other things, on the frequency content of the loads, as well as the interactions between the components of the multi-input loads. In this context, this paper proposes an approach to compare sets of variable amplitude multi-input loads applied on non-stiff structures. The comparison is done in terms of damage, with limited information on the structure where the loads sets are applied on. The methodology is presented, as well as an application. Activities planned to validate the methodology are also exposed.

APA, Harvard, Vancouver, ISO, and other styles

37

Rajendra Boopathy, Vijayanand, Anantharaman Sriraman, and Arumaikkannu G. "Energy absorbing capability of additive manufactured multi-material honeycomb structure." Rapid Prototyping Journal 25, no. 3 (April 8, 2019): 623–29. http://dx.doi.org/10.1108/rpj-03-2018-0066.

Full text

Abstract:

Purpose The present work aims in presenting the energy absorbing capability of different combination stacking of multiple materials, namely, Vero White and Tango Plus, under static and dynamic loading conditions. Design/methodology/approach Honeycomb structures with various multi-material stackings are fabricated using PolyJet 3D printing technique. From the static and dynamic test results, the structure having the better energy absorbing capability is identified. Findings It is found that from the various stacking combinations of multiple materials, the five-layered (5L) sandwich multi-material honeycomb structure has better energy absorbing capability. Practical implications This multi-material combination with a honeycomb structure can be used in the application of crash resistance components such as helmet, knee guard, car bumper, etc. Originality/value Through experimental work, various multi-material honeycomb structures and impact resistance of single material clearly indicated the inability to absorb impact loads which experiences a maximum force of 5,055.24 N, whereas the 5L sandwich multi-material honeycomb structure experiences a minimum force of 1,948.17 N, which is 38.5 per cent of the force experienced by the single material. Moreover, in the case of compressive resistance, 2L sandwich multi-material honeycomb structure experiences a maximum force of 5,887.5 N, whereas 5L sandwich multi-material honeycomb structure experiences a minimum force of 2,410 N, which is 40.9 per cent of the force experienced by two-layered (2L) sandwich multi-material honeycomb structure. In this study, the multi-material absorbed most of the input energy and experienced minimum force in both compressive and impact loads, thus showing its energy absorbing capability and hence its utility for structures that experience impact and compressive loads. A maximum force is required to deform the single and 2L material in terms of impact and compressive load, respectively, under maximum stiffness conditions.

APA, Harvard, Vancouver, ISO, and other styles

38

Lin, Yu-Hsien, and Cheng-Hao Yang. "Hydrodynamic Simulation of the Semi-Submersible Wind Float by Investigating Mooring Systems in Irregular Waves." Applied Sciences 10, no. 12 (June 22, 2020): 4267. http://dx.doi.org/10.3390/app10124267.

Full text

Abstract:

The present study aims to implement the software ANSYS AQWA to discuss the hydrodynamic analysis of the DeepCwind semi-submersible floating platform in waves based on the potential flow theory by considering the second-order wave exciting force. In this study, the linearized potential-flow hydrodynamic radiation and diffraction problems in the frequency domain were firstly solved by adopting the three-dimensional panel method. Subsequently, the hydrodynamic coefficients and wave loading data were transformed to time domain forms by the Cummins time domain equation as a system loading input. Furthermore, the quadratic transfer function (QTF) matrices with different frequencies and directions deduced based on the near field integration over the mean wetted hull surface were adopted for the calculation of slow-drift forces. In order to represent the damping in a real system for modeling potential flow without Morison’s elements, an additional quadratic damping matrix was added to capture the viscous drag. Eventually, both of the dynamic mooring model based on the lump-mass (LM) approach and the quasi-static mooring model based on the multi-segmented, quasi-static (MSQS) approach are introduced to discuss the mooring effect on the platform hydrodynamics. The effect of wave heading angles on the platform motion is considered as an influential parameter as well.

APA, Harvard, Vancouver, ISO, and other styles

39

Uotila, Valter, Jiaheng Lu, Dieter Gawlick, Zhen Hua Liu, Souripriya Das, and Gregory Pogossiants. "MultiCategory." Proceedings of the VLDB Endowment 14, no. 12 (July 2021): 2663–66. http://dx.doi.org/10.14778/3476311.3476314.

Full text

Abstract:

The variety of data is one of the important issues in the era of Big Data. The data are naturally organized in different formats and models, including structured data, semi-structured data, and unstructured data. Prior research has envisioned an approach to abstract multi-model data with a schema category and an instance category by using category theory. In this paper, we demonstrate a system, called MultiCategory, which processes multi-model queries based on category theory and functional programming. This demo is centered around four main scenarios to show a tangible system. First, we show how to build a schema category and an instance category by loading different models of data, including relational, XML, key-value, and graph data. Second, we show a few examples of query processing by using the functional programming language Haskell. Third, we demo the flexible outputs with different models of data for the same input query. Fourth, to better understand the category theoretical structure behind the queries, we offer a variety of graphical hooks to explore and visualize queries as graphs with respect to the schema category, as well as the query processing procedure with Haskell.

APA, Harvard, Vancouver, ISO, and other styles

40

Çelikkol, Emrullah, Mustafa Tümer, Ş. Hakan Atapek, and M. Zaim Kerimak. "A Fractographical Study on Dissimilar Weld Joints of SAF 2205 and Hastelloy C-276." MATEC Web of Conferences 188 (2018): 02018. http://dx.doi.org/10.1051/matecconf/201818802018.

Full text

Abstract:

In this study, a dissimilar weld joint between SAF 2205 and Hastelloy C-276 was manufactured by using gas tungsten arc welding and its notched impact fracture behaviour was investigated. Initially, V-type welding mouth was opened and the welding was performed by multi-pass. In welding procedure, ERNiCrMo-3 material used as a filler metal and the heat input was varied between 0.48-1.10 kJ/mm depending on welding parameters. Both welding pool and root zone were protected by an argon atmosphere. Multi notched impact tests were performed at room temperature. Weld metal had an impact toughness value as 92 J and its fracture surface exhibited several oriented cracking paths due to its solidified structure. The impact toughness value was measured as 82 J for heat affected zone of SAF 2205 and its fractograph reflected the coarser and deeper dimples. Heat affected zone of nickel based alloy had the highest impact toughness value as 116 J among the studied joints due to the more plastic deformation capability of nickel having face centered cubic structure, however, its fracture surface under impact loading exhibited several cracks propagating throughout the fusion line having equiaxed dendrites.

APA, Harvard, Vancouver, ISO, and other styles

41

Zhang, Yuyi, Joel P. Conte, Zhaohui Yang, Ahmed Elgamal, Jacobo Bielak, and Gabriel Acero. "Two-Dimensional Nonlinear Earthquake Response Analysis of a Bridge-Foundation-Ground System." Earthquake Spectra 24, no. 2 (May 2008): 343–86. http://dx.doi.org/10.1193/1.2923925.

Full text

Abstract:

This paper presents a two-dimensional advanced nonlinear FE model of an actual bridge, the Humboldt Bay Middle Channel (HBMC) Bridge, and its response to seismic input motions. This computational model is developed in the new structural analysis software framework OpenSees. The foundation soil is included to incorporate soil-foundation-structure interaction effects. Realistic nonlinear constitutive models for cyclic loading are used for the structural (concrete and reinforcing steel) and soil materials. The materials in the various soil layers are modeled using multi-yield-surface plasticity models incorporating liquefaction effects. Lysmer-type absorbing/transmitting boundaries are employed to avoid spurious wave reflections along the boundaries of the computational soil domain. Both procedures and results of earthquake response analysis are presented. The simulation results indicate that the earthquake response of the bridge is significantly affected by inelastic deformations of the supporting soil medium due to lateral spreading induced by soil liquefaction.

APA, Harvard, Vancouver, ISO, and other styles

42

Pietrzakowski, Marek. "An Active Functionally Graded Piezocomposite Plate Subjected to a Stochastic Pressure." Archives of Acoustics 40, no. 1 (March 1, 2015): 101–8. http://dx.doi.org/10.1515/aoa-2015-0012.

Full text

Abstract:

Abstract In the paper the analysis of random vibration of an actively damped laminated plate with functionally graded piezoelectric actuator layers is presented. The simply supported plate is subjected to stochastic loading represented by a uniformly distributed pressure. The random input is assumed as a Gaussian sta- tionary and ergodic process. The actuators are regarded as a multi-layer structure arranged of piezofiber composite sub-layers. The sub-layers differ each other with amount of PZT (lead-zirconate-titanate) fibers and are stacked to achieve a desired change of the PZT volume fraction through the actuator thickness. The gradation scheme of constituents and material properties are estimated by parabolic and power functions. Numerical simulations are performed to recognize the influence of the applied random excita- tions and the actuator properties gradations on the characteristics of the stochastic field of active plate deflection i.e. power spectral density, autocorrelation function and variance

APA, Harvard, Vancouver, ISO, and other styles

43

Tan, Shiyu, Jingbo Gao, Cong Wang, and Yingyong Shen. "Sensitivity analysis of antenna gain loss to the disturbance of control moment gyroscope." Journal of Physics: Conference Series 2472, no. 1 (May 1, 2023): 012027. http://dx.doi.org/10.1088/1742-6596/2472/1/012027.

Full text

Abstract:

Abstract The multi-body dynamic model of the SAR satellite and the Ruze formula are used to investigate the antenna gain loss’s sensitivity to the control moment gyroscope. First, by using the finite element method, the satellite’s dynamic model is created and the modal characteristic is then determined. Then the distribution of input disturbance and CMG diagram is established. And the effect of each CMG disturbance on the antenna gain is studied. The sensitivity parameters of gain loss to disturbance are computed by using the One-at-a-Time (OAT) method. The results show that for CMGs, although they are placed asymmetrically and have the same loading characteristics, their effects on the antenna gain are different and need to be considered separately. The method and ideas proposed in this paper can be used to quantify the influence of various disturbances’ sensitivity and control system design.

APA, Harvard, Vancouver, ISO, and other styles

44

Sun, Zhenye, Wei Zhu, Wen Shen, Emre Barlas, Jens Sørensen, Jiufa Cao, and Hua Yang. "Development of an Efficient Numerical Method for Wind Turbine Flow, Sound Generation, and Propagation under Multi-Wake Conditions." Applied Sciences 9, no. 1 (December 28, 2018): 100. http://dx.doi.org/10.3390/app9010100.

Full text

Abstract:

The propagation of aerodynamic noise from multi-wind turbines is studied. An efficient hybrid method is developed to jointly predict the aerodynamic and aeroacoustics performances of wind turbines, such as blade loading, rotor power, rotor aerodynamic noise sources, and propagation of noise. This numerical method combined the simulations of wind turbine flow, noise source and its propagation which is solved for long propagation path and under complex flow environment. The results from computational fluid dynamics (CFD) calculations not only provide wind turbine power and thrust information, but also provide detailed wake flow. The wake flow is computed with a 2D actuator disc (AD) method that is based on the axisymmetric flow assumption. The relative inflow velocity and angle of attack (AOA) of each blade element form input data to the noise source model. The noise source is also the initial condition for the wave equation that solves long distance noise propagation in frequency domain. Simulations were conducted under different atmospheric conditions which showed that wake flow is an important part that has to be included in wind turbine noise propagation.

APA, Harvard, Vancouver, ISO, and other styles

45

Yang, Kai, Zhong Shen Li, and Lei Zhang. "Research and Development of Automatic Control System on Material Split Packing and Packaging Integrated Machine." Applied Mechanics and Materials 533 (February 2014): 294–97. http://dx.doi.org/10.4028/www.scientific.net/amm.533.294.

Full text

Abstract:

In order to meet the high speed, high precision, high reliability of the packaging machine, a novel control system is provided. In the hardware, the main circuits consisted of main processor module, memory module, temperature measurement and control module, input signal detection module, material split packing module, output driver module, human-machine interface module, system monitor module, power module and JTAG debug module, etc. In the software, the multi-tasking operating system μC/OS-Ⅱ and the graphical user interface μC/GUI were successfully transplanted into LPC2478. Then an experimental platform was established. And many control tasks, including automatic measurement, making bags, loading, transferring, pumping vacuum, sealing and data display, were automatically and continuously executed on the platform. Finally the results show: the machine can package 30 packets (5 g per packet) in a minute; the packaging errors ≤ 0.2 g; the packaging qualified rates ≥ 93%. In conclusion, the system performance is good.

APA, Harvard, Vancouver, ISO, and other styles

46

Moravec, Jaromír, Josef Bradáč, and Iva Nováková. "Ways of Numerical Prediction of Austenitic Grain Size in Heat-Affected Zone of Welds." Advanced Materials Research 1029 (September 2014): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amr.1029.25.

Full text

Abstract:

In the present time there is a clear effort to achieve the most exact mathematical description of the behaviour of “Hi-tech” materials when exposed to temperature and stress loading. Besides the common numerically predicted values such as temperature, deformation and stress fields, or as the case may be structure changes during phase transformations, demands for prediction of the austenitic grain size in HAZ of welds become more and more frequent. That is why the present submission deals with the analysis of the determination of the grain size and grain growth kinetics of HR3C single-phase austenitic steel using the Monte Carlo Potts method. The procedure of obtaining the input data for numerical simulations will be demonstrated on HR3C steel, including the determination of grain growth kinetics and definition of all the parameters needed for a computational model. Results from the numerical simulation in Sysweld program will be then compared against the real experiment for a multi-layered weld made on HR3C tube.

APA, Harvard, Vancouver, ISO, and other styles

47

Jahrom, Saeed Ghaffarpour, and Mohammad Sharafuddin. "Determining the pile bearing capacity use of pda test results and neural networks." Acta Geotechnica Slovenica 17, no. 2 (2020): 26–33. http://dx.doi.org/10.18690/actageotechslov.17.2.34-45.2020.

Full text

Abstract:

The dynamic loading or PDA test is one of the on-site experiments to estimate the bearing capacity of a pile. This test is based on the wave-propagation theory and can provide a good estimate of the bearing capacity of a pile as well as an assessment of the health of the pile. In this research, using the results of 100 dynamic loading tests carried out with different piles and projects, three types of artificial neural network (ANN) have been used to estimate the load. Initially, the perceptron multi-layer neural network was one of the most used neural networks. Subsequently, the neuro-fuzzy network is used in a combination of neuro-fuzzy networks and, at the end of the radial-based neural network, a successful network was used for non-linear problems. Between the different models of the neural network used by researchers, the multi-layered perceptron network has a better performance. However, other networks used have also proven successful. Finally, different models of the neural networks were compared and the network that has the best performance was identified in both phases. The models based on neural networks, unlike conventional behavioral models, do not explain how the input parameters affect the output. In this research, by analyzing the sensitivity to the optimal structure of the introduced models in each step, we have tried to partly answer this question. Also, the extraction and presentation of the relations governing a neural network model to the user is more reliable in the use of such models, which facilitates the application of such models in engineering works. In this research, four first indicators were used to evaluate and compare the models and structures.

APA, Harvard, Vancouver, ISO, and other styles

48

Tho, Kee Kiat, Zongrui Chen, Chun Fai Leung, and Yean Khow Chow. "Enhanced analysis of pile flexural behavior due to installation of adjacent pile." Canadian Geotechnical Journal 51, no. 6 (June 2014): 705–11. http://dx.doi.org/10.1139/cgj-2013-0215.

Full text

Abstract:

The installation of piles causes lateral soil movements which will induce additional lateral loading on adjacent existing piles. A simplified two-stage approach is conventionally adopted to quantify the installation effect on an adjacent pile. The first stage involves estimating the free-field lateral soil movement profile due to the pile installation process, and this is then applied as input to a pile–soil interaction analysis in the second stage. Such an approach is computationally efficient, but its efficacy has not been rigorously assessed due to the lack of reliable rigorous reference solutions. In this study, the Eulerian finite element approach is applied to obtain rigorous reference solutions for the response of an existing pile due to the installation of an adjacent pile. The efficacy of the two-stage approach is then evaluated against these reference solutions. It is found that the bending moment profiles generated using the simplified two-stage approach deviate significantly from the reference solutions. The shortcomings of the existing two-stage approach are identified, and an improved analysis method denoted as the Enhanced Multi-Stage Approach is proposed and validated in this paper. The results based on the Enhanced Multi-Stage Approach are found to be in good agreement with the more rigorous reference solutions.

APA, Harvard, Vancouver, ISO, and other styles

49

Sellergren, Maja, Jing Li, Stina Drakare, and Sebastian Thöns. "Decision Support for Lake Restoration: A Case Study in Swedish Freshwater Bodies." Water 15, no. 4 (February 8, 2023): 668. http://dx.doi.org/10.3390/w15040668.

Full text

Abstract:

A considerable number of lakes in Sweden have high phosphorus internal loading from the sediments which cause cyanobacterial blooms every summer. Due to potential risks with such blooms for human health, drinking water supply, and ecosystem services, measures need to be taken to control the phosphorus content. Measures to control the phosphorus input from the surrounding land has been in focus. However, the measures have not been sufficient. This is because phosphorus deposited at the bottom of the lakes for many years are finally starting to leak to the water phase when the decomposition of sediments leads to anoxic conditions. In order to determine effective and efficient lake restoration measures, methods for lake restoration decision support by a multi-criteria analysis and the application of a decision analysis are developed. The multi-criteria analysis includes the determination of costs, longevity, and efficacy of six common lake restoration measures to reduce internal phosphorous loads in two lakes selected as a case study. The results show that aluminum treatment combines a highest efficacy with a high-cost efficiency being thus the optimal identified measure. The method involves adding an aluminum solution to the lakes’ sediment, which binds phosphorus, preventing it to be released to the water column. The multi-criteria model is integrated to a decision analytical model. The decision analytical model is used to identify the monetary socio-economic and environmental boundaries for the implementation of the optimal lake restoration measure.

APA, Harvard, Vancouver, ISO, and other styles

50

Sivrioglu, Selim, Fevzi Cakmak Bolat, and Ercan Erturk. "Active vibration control of a blade element with uncertainty modeling in PZT actuator force." Journal of Vibration and Control 25, no. 21-22 (August 6, 2019): 2721–32. http://dx.doi.org/10.1177/1077546319868883.

Full text

Abstract:

The aim of this research is to attenuate the vibrations of a blade structure with an attached piezoelectric actuator using robust multi-objective control. The force obtained from a piezoelectric patch loading has uncertainties due to the complicated shape (airfoil) of the blade element. A parameter-dependent model of the force equation is developed to understand the possible variation range of the actuation force. The modal analysis of the blade is performed to find vibration mode frequencies, and an aerodynamic load is generated experimentally to create steady-state vibration on the blade. A state-space model is obtained by considering certain vibration modes and the parameter-dependent part of the force in the input vector is taken outside of the plant model. The robust stability filter is modified with parameter dependency to have a cluster of the filter. Two different multi-objective controllers are designed with different design objectives. The designed controllers are implemented in experiments and performances of the controllers are compared using frequency and time domain responses. It is shown that the flexible blade vibrations are successfully suppressed with the proposed mixed norm robust controllers under the effect of steady-state aerodynamic disturbance with different air speeds. It is observed in experimental results that the performances of the [Formula: see text] controller are better than the [Formula: see text] controller.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Multi-input loading'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles