Nonlinear Flexural Vibrations of a Clamped Circular Plate

1972 ◽  
Vol 39 (4) ◽  
pp. 1050-1054 ◽  
Author(s):  
G. C. Kung ◽  
Y.-H. Pao
Keyword(s):  
Circular Plate ◽  
Theoretical Calculations ◽  
Flexural Vibration ◽  
Test Results ◽  
Response Curves ◽  
Axisymmetric Mode ◽  
Dependent Part ◽  
Plate Equations ◽  
Large Amplitude Vibrations ◽  
Good Agreement

Nonlinear flexural vibration of a circular plate clamped at its edge are investigated both experimentally and theoretically. The investigation has been restricted to the first axisymmetric mode. The time-dependent part of the nonlinear plate equations are reduced to Duffing’s equation by applying a one-term Ritz-Galerkin’s procedure. Test results are in good agreement with the theoretical calculations which indicate a non-linearity of hardening type for large amplitude vibrations. The period of vibration decreases by 35 percent when the amplitude is twice the thickness of the plate. The “jumps” in the amplitude-frequency response curves are observed to occur during a transition of a few seconds and are accompanied by a beating phenomenon.

On Carrying Capacity of Concrete Columniation in Seawater by Genetic Algorithms

2011 ◽  
Vol 71-78 ◽  
pp. 914-917
Author(s):  
Yue Zhong Lin
Keyword(s):  
Genetic Algorithms ◽  
Regression Model ◽  
Carrying Capacity ◽  
Theoretical Calculations ◽  
Test Results ◽  
Analysis Method ◽  
Relative Precision ◽  
Good Agreement

According to the data of carrying capacity of concrete columniation in seawater in different circulation times, a non-liner regression model is established between circulation times with carrying capacity of concrete columniation in this paper. The parameter is calculated by Genetic Algorithms, and then the carrying capacity of concrete columniation is calculated with the model. Good agreement is reached between the theoretical calculations with test results; the average relative precision is over 92%. As a result, it can be used to analyze the carrying capacity of concrete columniation in seawater. This analysis method is intelligent.

An Investigation of Face Type Magnetic Couplers

1996 ◽  
Vol 210 (4) ◽  
pp. 263-272 ◽  
Author(s):  
R Waring ◽  
J Hall ◽  
K Pullen ◽  
M R Etemad
Keyword(s):  
Theoretical Analysis ◽  
Optimum Design ◽  
Experimental Test ◽  
Axial Load ◽  
Filling Factor ◽  
Theoretical Calculations ◽  
Test Results ◽  
Face Type ◽  
Design And Manufacture ◽  
Good Agreement

A theoretical analysis of magnetic couplers is recounted, leading to the design and manufacture of prototype disc type magnetic couplers. Design and development of experimental test rigs are also given. Test results are presented and compared with theoretical calculations. This shows very good agreement. The exception to the rule was the case of axial load measurements, which were not accurately evaluated by the computations. The geometries tested here showed the optimum design to consist of rotors with eight poles, magnet thickness of 10 mm and a filling factor of about 0.7.

Theoretical and experimental research on slip and uplift of the timber-concrete composite beam

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7079-7099
Author(s):  
Jianying Chen ◽  
Guojing He ◽  
Xiaodong (Alice) Wang ◽  
Jiejun Wang ◽  
Jin Yi ◽  
...  
Keyword(s):  
Differential Equations ◽  
Deformation Theory ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Structural Element ◽  
Structural Efficiency ◽  
Theoretical Investigations ◽  
New Type ◽  
Interlayer Slip ◽  
Good Agreement

Timber-concrete composite beams are a new type of structural element that is environmentally friendly. The structural efficiency of this kind of beam highly depends on the stiffness of the interlayer connection. The structural efficiency of the composite was evaluated by experimental and theoretical investigations performed on the relative horizontal slip and vertical uplift along the interlayer between composite’s timber and concrete slab. Differential equations were established based on a theoretical analysis of combination effects of interlayer slip and vertical uplift, by using deformation theory of elastics. Subsequently, the differential equations were solved and the magnitude of uplift force at the interlayer was obtained. It was concluded that the theoretical calculations were in good agreement with the results of experimentation.

scholarly journals Spine Examination during COVID-19 Pandemic via Video Consultation

2021 ◽  
Author(s):  
Tom Jansen ◽  
Martin Gathen ◽  
Amadeo Touet ◽  
Hans Goost ◽  
Dieter Christian Wirtz ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Range Of Motion ◽  
Test Results ◽  
Risk Of Infection ◽  
Face To Face ◽  
Reliable Tool ◽  
Provocation Tests ◽  
Active Range Of Motion ◽  
Video Consultation ◽  
Good Agreement

Abstract Introduction During the current COVID-19 pandemic video consultations are increasingly common in order to minimize the risk of infection for staff and patients. The aim of this study was to evaluate the feasibility of a spine examination via video. Methods A total of 43 patients were recruited. Each participant underwent a video-based (VB) and a conventional face-to-face (FTF) spine examination. Pain intensity, active range of motion, inspection, a neurophysiologic basic exam and provocations tests were evaluated using video-based and face-to-face methods. Results The intra-rater reliability (IRR) was measured between both examinations. Good to very good IRR values were obtained in inspection (Kappa between 0,752 und 0,944), active range of motion and basic neurophysiological examination (Kappa between 0,659 und 0,969). Only moderate matches were found in specific provocation tests (Kappa between 0,407 und 0,938). A video-based spine examination is a reliable tool for measuring pain intensity, active range of motion and a basic neurophysiologic exam. Conclusion A basic spine examination during a video consultation is possible. A good agreement of the test results between video-based and face-to-face examination could be found.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

Investigating the vibrational behaviour of a rotating two-blade propeller by using a self-tracking method

2018 ◽  
Vol 233 (3) ◽  
pp. 835-847 ◽  
Author(s):  
Mohammad-Reza Ashory ◽  
Farhad Talebi ◽  
Heydar R Ghadikolaei ◽  
Morad Karimpour
Keyword(s):  
Natural Frequency ◽  
Measurement Errors ◽  
Mode Shapes ◽  
Model Parameters ◽  
Test Results ◽  
Modal Assurance Criterion ◽  
Tracking Method ◽  
Strong Resemblance ◽  
Test Scenarios ◽  
Good Agreement

This study investigated the vibrational behaviour of a rotating two-blade propeller at different rotational speeds by using self-tracking laser Doppler vibrometry. Given that a self-tracking method necessitates the accurate adjustment of test setups to reduce measurement errors, a test table with sufficient rigidity was designed and built to enable the adjustment and repair of test components. The results of the self-tracking test on the rotating propeller indicated an increase in natural frequency and a decrease in the amplitude of normalized mode shapes as rotational speed increases. To assess the test results, a numerical model created in ABAQUS was used. The model parameters were tuned in such a way that the natural frequency and associated mode shapes were in good agreement with those derived using a hammer test on a stationary propeller. The mode shapes obtained from the hammer test and the numerical (ABAQUS) modelling were compared using the modal assurance criterion. The examination indicated a strong resemblance between the hammer test results and the numerical findings. Hence, the model can be employed to determine the other mechanical properties of two-blade propellers in test scenarios.

scholarly journals Etude par résonance magnétique nucléaire de composés organiques contenant des chalcogènes. II. L'éther de diphényle et ses analogues soufré, sélénié et telluré

1979 ◽  
Vol 57 (22) ◽  
pp. 2967-2970 ◽  
Author(s):  
Gabriel Llabrès ◽  
Marcel Baiwir ◽  
Léon Christiaens ◽  
Jean-Louis Piette
Keyword(s):  
Crystal Structure ◽  
Theoretical Calculations ◽  
Heavy Atom ◽  
Mesomeric Effect ◽  
Heavy Atom Effect ◽  
Inductive Effects ◽  
Structure Determinations ◽  
Résonance Magnétique ◽  
Atom Effect ◽  
Good Agreement

The 1Hmr study of the title compounds has revealed a screw conformation, with defined interconversion processes, in good agreement with crystal structure determinations and theoretical calculations. The mesomeric effect of the heteroatom is smaller than in the anisole series, due to steric inhibitions.The 13Cmr enhances, to some extent, these conclusions. In the case of Te compounds, a heavy atom effect adds to the classical mesomeric and inductive effects to account for the experimental observations.

Experimental Study and Finite Analysis on Flexural Capacity of Laminated Glass

2011 ◽  
Vol 243-249 ◽  
pp. 258-262
Author(s):  
Jun Chen ◽  
Jia Lv ◽  
Qi Lin Zhang ◽  
Zhi Xiong Tao ◽  
Jun Chen
Keyword(s):  
Experimental Results ◽  
Laminated Glass ◽  
Test Results ◽  
Design Code ◽  
Flexural Capacity ◽  
Equivalent Thickness ◽  
High Rise ◽  
Safety Glass ◽  
Current Design ◽  
Good Agreement

Laminated glass has been increasing widely used in high rise buildings as a kind of safety glass in recent years. So we should analyze its material property. In this paper, we use flexural experiments and ANSYS program to analyze the main factors that affect the flexural capacity of the laminated glass. The test results show that the flexural capacity is closely related to film. And the ANSYS program had got good agreement with the experimental results. Comparison of experimental results with calculated ones indicates that the current design code will lead to conservative results and the equivalent thickness of laminated glasses provided in the code should be further discussed.

Experimental and theoretical study of sandwich composites with Z-pins under quasi-static compression loading

2021 ◽  
pp. 136943322110073
Author(s):  
Erdem Selver ◽  
Gaye Kaya ◽  
Hussein Dalfi
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Critical Role ◽  
Sandwich Composites ◽  
Test Results ◽  
Compressive Properties ◽  
Element Analysis ◽  
Static Compression ◽  
Quasi Static Compression ◽  
Good Agreement

This study aims to enhance the compressive properties of sandwich composites containing extruded polystyrene (XPS) foam core and glass or carbon face materials by using carbon/vinyl ester and glass/vinyl ester composite Z-pins. The composite pins were inserted into foam cores at two different densities (15 and 30 mm). Compression test results showed that compressive strength, modulus and loads of the sandwich composites significantly increased after using composite Z-pins. Sandwich composites with 15 mm pin densities exhibited higher compressive properties than that of 30 mm pin densities. The pin type played a critical role whilst carbon pin reinforced sandwich composites had higher compressive properties compared to glass pin reinforced sandwich composites. Finite element analysis (FE) using Abaqus software has been established in this study to verify the experimental results. Experimental and numerical results based on the capabilities of the sandwich composites to capture the mechanical behaviour and the damage failure modes were conducted and showed a good agreement between them.

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