Accounting for Shear Deformation in the Problem of Vibrations and Dissipative Heating of Flexible Viscoelastic Structural Element with Piezoelectric Sensor and Actuator

2020 ◽  
pp. 51-69
Author(s):  
I. F. Kirichok ◽  
Y. A. Zhuk ◽  
S. Yu. Kruts
Keyword(s):  
Shear Deformation ◽  
Piezoelectric Sensor ◽  
Dissipative Heating ◽  
Structural Element

Application of Piezo Sensors in EMI and Guided Wave Techniques

2013 ◽  
Vol 569-570 ◽  
pp. 702-709
Author(s):  
Pawel Malinowski ◽  
Lukasz Skarbek ◽  
Wieslaw Ostachowicz
Keyword(s):  
Wave Propagation ◽  
Laser Scanning ◽  
Guided Waves ◽  
Damage Index ◽  
Piezoelectric Sensor ◽  
Guided Wave ◽  
Structural Element ◽  
Electromechanical Impedance ◽  
Impedance Characteristics ◽  
Narrowband Signal

In reported research piezoelectric sensors were used for damage identicitaion purposes. Piezoelectric sensor was used for specimen excitation. Two techniques were investigated. The Electromechanical impedance (EMI) technique and guided wave based technique. The principle of EMI technique is based on measurement and analysis of impedance of piezoelectric transducers bonded on or embedded in investigated structure. It is assumed that structural change should influence the impedance characteristics of the transducers. The guided wave based technique is based on the guided elastic wave propagation phenomena. This type of waves can be used in order to obtain information about structure condition and possibly damaged areas. In reported investigation piezoelectric sensor was used to excite guided waves in chosen structural element. Dispersive nature of guided waves results in changes of velocity with the wave frequency, therefore a narrowband signal was used to minimize the dispersion phenomenon. The generated signal was amplified before applying it to the transducer in order to ensure measurable amplitude of excited guided wave. Measurement of the wave field was realized using laser scanning vibrometer that registered the velocity responses at a points belonging to a defined mesh. This non-contact tool allowed to investigate phenomena related to wave propagation. For both techniques numerical signals processing tools were developed. These numerical tools were designed to extract damage relevant features from EMI measurements and guided wave propagation measurements. The damage index (DI) was introduced on the basis of the extracted features.

Application Of Electron Probe Analyses Of Minerals In Discussing The Relationship Between Ductile Deformation And Metamorphism

1990 ◽  
Vol 48 (2) ◽  
pp. 250-251
Author(s):  
Fan Guochuan ◽  
Sun Zhongshi
Keyword(s):  
Chemical Composition ◽  
Shear Deformation ◽  
Electron Probe ◽  
General Rule ◽  
Granulite Facies ◽  
Ductile Deformation ◽  
Higher Temperature ◽  
Ductile Shear ◽  
The Relationship ◽  
Ductile Shear Deformation

Under influence of ductile shear deformation, granulite facies mineral paragenesis underwent metamorphism and changes in chemical composition. The present paper discusses some changes in chemical composition of garnet in hypers thene_absent felsic gnesiss and of hypersthene in rock in early and late granulite facies undergone increasing ductile shear deformation .In garnet fetsic geniss, band structures were formed because of partial melting and resulted in zoning from massive⟶transitional⟶melanocrate zones in increasing deformed sequence. The electron-probe analyses for garnet in these zones are listed in table 1 . The Table shows that Mno, Cao contents in garnet decrease swiftly from slightly to intensely deformed zones.In slightly and moderately deformed zones, Mgo contents keep unchanged and Feo is slightly lower. In intensely deformed zone, Mgo contents increase, indicating a higher temperature. This is in accord with the general rule that Mgo contents in garnet increase with rising temperature.

Bioavailability of naringenin chalcone in humans after ingestion of cherry tomatoes

2020 ◽  
Vol 90 (5-6) ◽  
pp. 411-416 ◽  
Author(s):  
Carina Kolot ◽  
Ana Rodriguez-Mateos ◽  
Rodrigo Feliciano ◽  
Katharina Bottermann ◽  
Wilhelm Stahl
Keyword(s):  
Plasma Levels ◽  
Average Concentration ◽  
Biologically Active ◽  
Thiol Groups ◽  
Structural Element ◽  
Active Molecule ◽  
Reactive Center ◽  
Average Maximum ◽  
Alpha Beta ◽  
Cherry Tomatoes

Abstract. Chalcones are a type of flavonoids characterized by an α-β unsaturated structural element which may react with thiol groups to activate pathways such as the Nrf2-Keap-1 system. Naringenin chalcone is abundant in the diet but little is known about its bioavailability. In this work, the bioavailability of naringenin chalcone from tomatoes was investigated in a group of healthy men (n=10). After ingestion of 600 grams of tomatoes providing a single dose of 17.3 mg naringenin chalcone, 0.2 mg of naringenin, and 195 mg naringin plasma levels of free and conjugated naringenin and naringenin chalcone (glucuronide and sulfate) were analyzed by UHPLC-QTOF-MS at 0.5, 1, 3, and 6 h post-consumption. Plasma levels of conjugated naringenin increased to about 12 nmol/L with a maximum at about 3 h. Concentrations of free naringenin hardly elevated above baseline. Plasma levels of free and conjugated naringenin chalcone significantly increased. A maximum of the conjugated chalcone was reached at about 3 h after ingestion with an average concentration of about 0.5 nmol/L. No free chalcone was detectable at baseline but low amounts of the unconjugated compound could be detected with an average maximum of 0.8 nmol/L at about 1 h after ingestion. The data demonstrate that naringenin chalcone is bioavailable in humans from cherry tomatoes as a dietary source. However, availability is poor and intramolecular cyclisation as well as extended metabolism likely contribute to the inactivation of the reactive alpha-beta unsaturated reactive center as well as the excretion of the biologically active molecule, respectively.

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.

In-Plane Bending and Shear Deformation of Belt Contributions on Tire Cornering Stiffness Characteristics

2020 ◽  
Author(s):  
Gibin Gil ◽  
Sujin Lee
Keyword(s):  
Mathematical Model ◽  
Shear Deformation ◽  
Beam Theory ◽  
Slip Angle ◽  
Wear Properties ◽  
Angle Change ◽  
Foundation Model ◽  
Plane Bending ◽  
Stiffness Characteristics ◽  
Brush Model

ABSTRACT In radial tires, belt structure plays a role of minimizing the lateral deflection of carcass, which has a significant influence on the cornering and wear properties of a tire. The deflection of carcass affects the magnitude of tread block deformation when the tire is under the slip angle. As a result, it can change the cornering stiffness characteristics of the tire, especially when the vertical load is high. During tire development, a tire design engineer tries to find the optimal belt ply angle that satisfies the various performance requirements simultaneously, but it is not an easy task because the effect of belt angle change is different depending on the size of the tire. There have been many attempts to construct a mathematical model that represents the structural properties of the belt package, including the string-based model and the beam on elastic foundation model. But, in many cases, only the in-plane bending of belt is considered and the shear deformation is not taken into consideration. In this study, the effect of belt angle change on belt stiffness is analyzed using a mathematical model based on the Timoshenko beam theory. This model can account for the in-plane bending and shear deformation of the belt structure at the same time. The results of the analysis show how the contribution of bending and shear is changed depending on a tire design parameter, herein the belt cord angle. The effect of belt ply angle change on cornering stiffness is investigated by means of the brush model including belt flexibility. The prediction by the brush model is compared with the measurement using a Flat-trac machine, and the validity of the model is discussed.

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