scholarly journals A Double-Acting Piezoelectric Actuator for Helicopter Active Rotor

Actuators ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 247
Author(s):  
Jinlong Zhou ◽  
Linghua Dong ◽  
Weidong Yang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Performance Test ◽  
Failure Modes ◽  
Element Model ◽  
Test Results ◽  
Trailing Edge ◽  
Trailing Edge Flaps ◽  
Piezoelectric Stacks

An active rotor with trailing-edge flaps is an effective approach to alleviate vibrations and noise in helicopters. In this study, a compact piezoelectric actuator is proposed to drive trailing-edge flaps. The two groups of piezoelectric stacks accommodated in the actuator operate in opposition, and double-acting output can be realized through the differential motion of these stacks. A theoretical model and a finite element model are established to predict the output capability of this actuator, and structural optimization is performed using the finite element model. A prototype is built and tested on a benchtop to assess its performance. Test results demonstrate that the actuator stiffness reaches 801 N/mm, and its output stroke is up to ± 0.27 mm when subjected to actuation voltage of 120 V. Agreement between measurements and simulations validates the accuracy of the established models. In addition, actuator outputs in failure modes are measured by canceling the supply voltage of one group of piezoelectric stacks. In this condition, the actuator can still generate acceptable outputs, and the initial position of the output end remains unchanged. Simulations and test results reveal that the proposed actuator achieves promising performance, and it is capable to be applied to a helicopter active rotor.

Finite element modelling and design of composite bridges with profiled steel sheeting

2016 ◽  
Vol 20 (9) ◽  
pp. 1406-1430 ◽  
Author(s):  
Ehab Ellobody
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Finite Element Models ◽  
Test Results ◽  
Composite Bridges ◽  
European Code ◽  
Composite Bridge

This article discusses the non-linear analysis and design of highway composite bridges with profiled steel sheeting. A three-dimensional finite element model has been developed for the composite bridges, which accounted for the bridge geometries, material non-linearities of the bridge components, bridge boundary conditions, shear connection, interactions among bridge components and bridge bracing systems. The simply supported composite bridge has a span of 48 m, a width of 13 m and a depth of 2.3 m. The bridge components were designed following the European code for steel–concrete composite bridges. The live load acting on the bridge was load model 1, which represents the static and dynamic effects of vertical loading due to normal road traffic as specified in the European code. The finite element model of the composite bridge was developed depending on additional finite element models, developed by the author, and validated against tests reported in the literature on full-scale composite bridges and composite bridge components. The tests had different geometries, different boundary conditions, different loading conditions and different failure modes. Failure loads, load–mid-span deflection relationships, load–end slip relationships, failure modes, stress contours of the composite bridge as well as of the modelled tests were predicted from the finite element analysis and compared well against test results. The comparison with test results has shown that the finite element models can be effectively used to provide more accurate analyses and better understanding for the behaviour and design of composite bridges with profiled steel sheeting. A parametric study was conducted on the composite bridge highlighting the effects of the change in structural steel strength and concrete strength on the behaviour and design of the composite bridge. This study has shown that the design rules specified in the European code are accurate and conservative for the design of highway steel–concrete composite bridges.

Aluminium alloy channels subjected to web crippling

2019 ◽  
Vol 22 (7) ◽  
pp. 1617-1630 ◽  
Author(s):  
Feng Zhou ◽  
Ben Young
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Aluminium Alloy ◽  
Failure Modes ◽  
Element Model ◽  
Test Results ◽  
Web Crippling ◽  
Web Buckling ◽  
The Finite Element Model ◽  
The Web

This article reports experimental and numerical investigations of aluminium alloy plain and lipped channels subjected to web crippling. A total of 240 data are presented that include 24 test results and 216 numerical results. A series of tests was conducted first on channels fabricated by extrusion using 6063-T5 and 6061-T6 heat-treated aluminium alloys under end-two-flange and interior-two-flange loading conditions. The concentrate transverse loads were applied by means of bearing plates. The flanges of the specimens were not fastened (unrestrained) to the bearing plates. A non-linear finite element model is then developed and verified against experimental results. Geometric and material non-linearities were included in the finite element model. It was shown that the finite element model closely predicted the web crippling strengths and failure modes of the tested specimens. Hence, the model was used for an extensive parametric study of cross-section geometries, and the web slenderness value ranged from 24.0 to 207.3. The test results and the web crippling strengths predicted from the finite element analysis were compared with the design strengths obtained using the American, Australian/New Zealand and European specifications for aluminium structures. An empirical unified web crippling equation with new coefficients for aluminium alloy channels under end-two-flange and interior-two-flange loading conditions is proposed. Since two failure modes of web buckling and web yielding were observed in the tests, the web crippling strength is also predicted using the proposed theoretical design rules for channels. The web crippling strength is the lesser of the web buckling strength and web yield strength.

Research on seismic behavior of special-shaped CFST column to H-section steel beam joint

2021 ◽  
pp. 136943322110073
Author(s):  
Yu Cheng ◽  
Yuanlong Yang ◽  
Binyang Li ◽  
Jiepeng Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Joint Stiffness ◽  
Load Ratio ◽  
Element Model ◽  
Steel Tube ◽  
Steel Beam ◽  
Static Test

To investigate the seismic behavior of joint between special-shaped concrete-filled steel tubular (CFST) column and H-section steel beam, a pseudo-static test was carried out on five specimens with scale ratio of 1:2. The investigated factors include stiffening types of steel tube (multi-cell and tensile bar) and connection types (exterior diaphragm and vertical rib). The failure modes, hysteresis curves, skeleton curves, stress distribution, and joint shear deformation of specimens were analyzed to investigate the seismic behaviors of joints. The test results showed the connections of exterior diaphragm and vertical rib have good seismic behavior and can be identified as rigid joint in the frames with bracing system according to Eurocode 3. The joint of special-shaped column with tensile bars have better seismic performance by using through vertical rib connection. Furthermore, a finite element model was established and a parametric analysis with the finite element model was conducted to investigate the influences of following parameters on the joint stiffness: width-to-thickness ratio of column steel tube, beam-to-column linear stiffness ratio, vertical rib dimensions, and axial load ratio of column. Lastly, preliminary design suggestions were proposed.

Thermo-Mechanical Analysis of Instrumentation Guide Tube Failure During a Severe Accident in a Nordic Boiling Water Reactor

2020 ◽  
Author(s):  
Ying Yue ◽  
Walter Villanueva ◽  
Hongdi Wang ◽  
Dingqu Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Boiling Water ◽  
Severe Accident ◽  
Boiling Water Reactor ◽  
Guide Tube ◽  
Water Reactor ◽  
Water Reactors

Abstract Vessel penetrations are important features of both pressurized water reactors and boiling water reactors. The thermal and structural behaviour of instrumentation guide tubes (IGTs) and control rod guide tubes (CRGTs) during a severe accident is vital in the assessment of the structure integrity of the reactor pressure vessel. Penetrations may fail due to welding failure, nozzle rupture, melt-through, etc. It is thus important to assess the failure mechanisms of penetrations with sufficient details. The objective of this paper is to assess the timing and failure modes of IGTs at the lower head during a severe accident in a Nordic boiling water reactor. In this study, a three-dimensional local finite element model was established using Ansys Mechanical that includes the vessel wall, the nozzle, and the weld joint. The thermo-mechanical loads of the finite element model were based on MELCOR results of a station blackout accident (SBO) combined with a large-break loss-of-coolant accident (LBLOCA) including an external vessel cooling by water as a severe accident management strategy. Given the temperature, creep strain, elastic strain, plastic strain, stress and displacement from the ANSYS simulations, the results showed the timing and failure modes of IGTs. Failure of the IGT penetration by nozzle creep is found to be the dominant failure mode of the vessel. However, it was also found that the IGT is clamped by the flow limiter before the nozzle creep, which means that IGT ejection is unlikely.

scholarly journals Combining Models to Simulate the Condition of the PVC Distribution Network

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 591
Author(s):  
Karel A. van Laarhoven ◽  
Bas A. Wols
Keyword(s):  
Finite Element ◽  
Drinking Water ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Angular Deflection ◽  
Soil Settlement ◽  
Overall Performance ◽  
Water Companies ◽  
Maintenance And Inspection

The failure of joints plays an important role in the overall performance of mains. One of the prevalent failure modes at polyvinyl chloride (PVC) joints is the rupture of pipe or joint, which may occur due to high angular deflection of the pipe with respect to the joint, caused by differential soil settlement. The present paper reports the construction and use of a finite element model to determine the maximum angular deflection of a variety of PVC joints in different loading situations. The resulting acceptable deflections vary between 3° and 8° per side, which differs significantly from installation guidelines. The results will support drinking water companies in substantiating the prioritization of maintenance and inspection.

Displacement Properties of Newly Developed 3-Dimensional Piezoelectric Actuator at Various AC Frequencies

2007 ◽  
Vol 534-536 ◽  
pp. 1441-1444 ◽  
Author(s):  
Man Soon Yoon ◽  
Y.G. Choi ◽  
Soon Chul Ur
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Element Model ◽  
Vibration Modes ◽  
Maximum Strain ◽  
Electromechanical Properties ◽  
3 Dimensional ◽  
The Finite Element Model ◽  
Good Agreement

The electromechanical properties of a newly proposed 3-dimensional piezoelectric actuator have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data was in good agreement with the finite element model analysis of strains and vibration modes. Moreover, the field -induced displacement stability of dome-shaped 3- dimensional piezoelectric actuator at various ac freguencies was superior to Rainbow actuator.

Tension and shear block failure of bolted gusset plates

2006 ◽  
Vol 33 (4) ◽  
pp. 395-408 ◽  
Author(s):  
Bino B.S Huns ◽  
Gilbert Y Grondin ◽  
Robert G Driver
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Test Results ◽  
Limit States ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Current Design ◽  
Shear Block ◽  
The Finite Element Model

Despite the large database of test results for tension and shear block failure in gusset plates, the exact progression of the failure mechanism is not clear. Although current design equations predict the capacity of gusset plates fairly well, it is important for a design equation to not only predict the capacity reliably but also reflect the failure mode accurately. Recent experimental and numerical research has indicated that current design equations do not always predict the failure behaviour accurately. A finite element model was therefore developed to predict the sequence of events that leads to the tear-out of a block of material from a bolted gusset plate in tension. The model was developed to provide a useful tool for studying tension and shear block failure in gusset plates and other structural elements. This paper presents the development of the finite element model and procedure for prediction of tension and shear block failure in gusset plates. Making use of the finite element model, the database of test results is also expanded to include gusset plates with a larger number of transverse lines of bolts than what has been obtained experimentally. A reliability analysis is used to assess several design equations, including the equation adopted in CAN/CSA-S16-01 and a unified equation proposed recently for several types of bolted connections. From this work, a limit states design equation is proposed for gusset plates.Key words: gusset plate, limit states design, reliability, shear rupture, tension rupture, finite element analysis, failure criterion.

scholarly journals Performance of low rise concealed truss composite shear walls with external columns

2018 ◽  
Vol 38 (2) ◽  
pp. 131-142
Author(s):  
Dan Zhang ◽  
Zhong Tao ◽  
Lei Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Studies ◽  
Shear Walls ◽  
Element Model ◽  
Monotonic Loading ◽  
Test Results ◽  
Flat Steel ◽  
Composite Shear ◽  
Constant Axial Load

A review on the previous studies shows that limited analytical or experimental studies on the low-rise concealed truss shear walls with external columns under monotonic loading have already been conducted. The combination of concealed truss was welded to I-shaped steel frame and flat steel support. Two different aspect ratio composite shear walls were tested under static monotonic loading, and the failure mode, bearing capacity, ductility and stiffness were explored. A finite element model was developed and used to simulate the composite shear walls under constant axial load and lateral loading. The comparison of test results confirmed that the finite element model could predict the behavior of composite shear walls accurately. Meanwhile, stress analyses of the specimens were studied to simulate stress distribution of reinforcement, and to analyze the steel of composite shear wall with external columns at different loading stages. Taken together, this study could be a basis for developing an accurately simplified model.

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