Quasi-static displacement

The connection was comprised of a W14 x 233 column, a W30 x 108 beam, and a pair of N2.1 brackets. The connection was tested using cyclic quasi-static displacements applied at the beam tip as shown in Fig. 10. The columns were... 

The experimental results showed that a linear relationship exists between the voltage output and imposed quasi-static displacement of the tip of the IPMC sensor as shown in Figure 3. The experimental set up was such that the tip of the cantilevered IPMC strip as shown in Figure 2 was mechanically moved and the corresponding output voltage recorded. The results are shown in Figure 3. 

In the following sections, at first, the concept of GNSS positioning analysis is mentioned. And after that, examples of usage of GNSSs in earthquake engineering are described, such as time synchronization, observation of quasi-static displacements of the Earth s surface, and measiue-ment of the dynamic displacement. 

Coseismic displacements have been measured for studying geometry of fault surface. The surface displacement of the Earth is associated with the slip on the fault surface through mathematical models. The radiated seismic wave field is dependent on the slip amplitude, mpture velocity, and source time function, whereas the quasi-static displacements depend only on the final slip amplitude. Therefore, the displacements measured with GNSS are complementary constraints on the geometry of fault surface (Segall and Davis 1997). 

Rs(t) are the support forces necessary to statically impose displacements that vary with time obviously, varies with time and is therefore known as the vector of quasi-static displacements. Observe that Rs(t) = 0 in the case of identical support ground motion. The displacements of the superstructure U are known as dynamic displacements. 

This relatimi also enables us to express the quasi-static displacement in terms of the specified support displacements v ... 

The total dynamic and quasi-static displacements are hence... 

Since polymers are viscoelastic materials it is necessaiy to specify both the temperature and the time scale under which the result was obtained. This protocol is meant for low speed ( quasi-static ) displacement contrd mode of loading and as a bade test condition, it is recommended that 23°C and a load-point displacement rate of 10 mm/min be used, but other conditions are possible. Li all cases, the time-D-ffacture should be quoted and all related determinations (yield stress and indentation correction, see below) should be obtained at comparable loading times as for the fracture test... 

Far from a wellbore, the velocity of reservoir fluids is about one linear foot per day. Near a wellbore, the velocity can increase one-hundred fold. A static or quasi-static test such as the sessile drop (contact angle) test may not represent the dynamic behavior of the fluids in the field. The dynamic Wilhelmy device gives results which are comparable in interface velocity to the field displacement rate. The interface in the Wilhelmy test described here moved at a steady rate of 0.127 mm/sec or 36 ft/day. The wetting cycle for a hybrid-wetting crude oil system was not affected by moving at a rate less than 1 ft/day. 

The Pb - (Mg/Nb) peak of the DPDF at 3.5 A splits into two subpeaks dynamically below Tj, and quasi-statically below T. This result is consistent with the local Pb displacement along the [1 0 0] direction. Among the six [10 0] type directions the one with most Mg " " neighbors will be chosen as the local off-centering direction of each Pb " " ion, so the neighboring Pb ions may choose different off-centering directions. The polar clouds formed below Td but above are purely dynamic, and its polarization also fluctuates with time. 

In the first part of this chapter we studied the radial vibrations of a solid or hollow sphere. This problem was considered an extension to the dynamic situation of the quasi-static problem of the response of a viscoelastic sphere under a step input in pressure. Let us consider now the simple case of a transverse harmonic excitation in which separation of variables can be used to solve the motion equation. Let us assume a slab of a viscoelastic material between two parallel rigid plates separated by a distance h, in which a sinusoidal motion is imposed on the lower plate. In this case we deal with a transverse wave, and the viscoelastic modulus to be used is, of course, the shear modulus. As shown in Figure 16.7, let us consider a Cartesian coordinate system associated with the material, with its X2 axis perpendicular to the shearing plane, its xx axis parallel to the direction of the shearing displacement, and its origin in the center of the lower plate. Under steady-state conditions, each part of the viscoelastic slab will undergo an oscillatory motion with a displacement i(x2, t) in the direction of the Xx axis whose amplitude depends on the distance from the origin X2-... 

The heart of force detection in an AFM apparatus is a scanning cantilever microfabricated with a tip for force sensing (Figure 6.29). Forces generated by surface-to-tip interactions, Fst> lead to vertical tip displacements, Az, that are related to each other in a quasi-static way and to a hrst approximation by a form of the Hooke s law equation ... 

Fig. 25.13 Ultrasonic transmission measurement results (excitation RF peak power 1.85 kW) carried out on samples of two aluminum plates 5 mm thick bonded together by an adhesive epoxy layer of 30-50 pm thickness during quasi-static tension loading (displacement rate 0.5 pm s ) until fracture. The amplitudes of the fundamental frequency transmitted through (a) a weak...

Quasi-static and dynamic tests were conducted at the DLR Institute of Stmctores and Design, Stuttgart. The quasi-static test was conducted in a Zwick 1494 servo-hydraulic uniaxial loading frame (max. loads 500 kN, max. crosshead displacement 850 mm) with the stmcture test setup as shown in Figure 10.14(a). Vertical compression loads were applied by the test machine crosshead via a load cell to the test stmcture through the I-beam and measured at the load cell and on the load platform. The test was performed initially at a crosshead velocity of 5 mm/min for the first 20 mm of crosshead displacement, then increased and maintained at 20 mm/min until final collapse at 62 mm crosshead displacement. From the measured load-deflection curve the absorbed energy at failure can be calculated, which was measured to be 6.3 kJ at 62 mm displacement. This energy represents... 

A summary of the test conditions and results is detailed in Table 10.2, which shows total mass inclusive of drop sled, I-beam, added mass and mass of frame stmcture, the absorbed energy by the frame stmcture and the cmsh distances. The measured force—displacement curves from the quasi-static and dynamic tests are presented in Figure 10.16. The load levels plotted for each of the tests conducted are a summation of the three force transducers in the impact platform. These curves exhibit characteristics typical of those seen in Section 10.3 for progressively cmshed... 

Figure 10.16 Force—displacement responses measured in quasi-static and dynamic frame tests.

The scalability of the model has been validated experimentally. Fig. 5.6(a) shows the measured and model-predicted quasi-static tip force output versus tip bending displacement under a constant actuation voltage, for three samples with width of 3.5 mm but different lengths. Fig. 5.6(b) shows the same for another set of three samples with width of 6 mm. From Fig. 5.6, good agreement can be seen between the measurements and the model predictions for both sets of samples. 

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