Деламинация плоской адгезионной зоны при комбинированных динамических воздействиях

In this article explores the problem of destruction of layered media under combined dynamic load. The research is aimed at the influence of background harmonic oscillations on the amplitude of the main force pulse. In previous works,results were obtained for a simple one - dimensional model - a string on an elastic base. As a result, it turned out that it is possible to significantly reduce the value of the critical amplitude of the destructive effect due to the correct selection of the excitation frequency. This effect is observed even at low intensities of the background field. The criterion of incubation time was used as a condition for breaking the adhesive layer. In this paper, we will also investigate the features of the fracture as a consequence of the combined effect of the force and the external harmonic field. However, the results obtained in this paper will be presented for a two - dimensional model - a circular membrane on an elastic base. You will notice that there is a similar effect, as in the case of strings. External background field tuned to a certain frequency can significantly reduce the value of the critical amplitude of the separation of the adhesive layer. The incubation time criterion will also be used as a destructioncriterion.

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MECHANICAL MODELING AND EXPERIMENTAL VALIDATION ON PIEZOCERAMIC BASED ON THE SURFACE-BONDED PZT SENSOR

Surface Review and Letters ◽

10.1142/s0218625x18502098 ◽

2019 ◽

Vol 26 (06) ◽

pp. 1850209

Author(s):

YANYU MENG ◽

SHI YAN ◽

XIAOLONG WEN

Keyword(s):

Output Voltage ◽

Excitation Frequency ◽

Adhesive Layer ◽

Signal Acquisition ◽

Mechanical Modeling ◽

Signal Loss ◽

Harmonic Force ◽

Force Amplitude ◽

Sensor Modeling ◽

Better Than

This paper proposes the modified mechanical and mathematical modeling of lead zirconium titanate (PZT) sensor based on the PZT constitutive relation in order to solve the complicated boundary condition and stress situation of PZT sensor due to the effect of adhesive-layer damping. The experimental study on the surface-bonded PZT sensor is chosen to carry out the correctness of the proposed models. The results show that the PZT sensor modeling is simplified to three types. When the amplitude of harmonic force is constant, the greater the excitation frequency, the more sensitive the output voltage is, the easier the signal acquisition is. At a certain frequency, the voltage output is proportional to the force amplitude. The larger the area or thickness of PZT, the greater the output voltage is, the more sensitive the signal output is. The output voltage is in quadratic relation to the bonding thickness. Furthermore, the smaller the output voltage, the greater the damping is. The signal loss is about 25.82%. The signal acquisition effect of the PZT square wafer is better than that of circular wafer under the same area of PZT sensor. The research achievements reveal the sensing mechanisms and validate the efficiency of the developed model and effectively simulate and detect direct piezoelectric rule of PZT sensor.

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Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

Swiss Journal of Psychology ◽

10.1024//1421-0185.61.1.34 ◽

2002 ◽

Vol 61 (1) ◽

pp. 34-44 ◽

Cited By ~ 8

Author(s):

Eric Tafani ◽

Lionel Souchet

Keyword(s):

Higher Education ◽

Social Representations ◽

Cognitive Restructuring ◽

Social Representation ◽

Two Dimensional ◽

Dimensional Model ◽

Social Actions ◽

The Social ◽

Two Dimensional Model ◽

Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

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