Load displacement history

Experimental load-displacement history and creep data were used to estimate the partitioned viscoplastic constitutive properties. Load isplacement loops from double lap-shear tests were used in conjunction with finite element (FE) models to refine the estimates of the effective viscoplastic constitutive properties of the three Pb-free solders and eutectic Sn Pb. The constitutive equations for the four solders were used as initial estimates when iterating to match experimental and predicted hysteresis loops. That is, experimentally determined double lap-shear specimen load-displacement hysteresis loops were compared with the FE simulations. The constitutive properties were then adjusted iteratively to improve agreement the equations and properties are presented in Table 16. 

Fig. 6 TDCB results of tests performed at 1 mm/min, at 23°C. Comparison of FV and experimental results (a) Load/Displacement curves (b) Crack length histories. CZM parameters XD1493 - = 33.6 MPa, G, = 5037 JW XD4600 - cr , = 59.8 MPa, Gc =...

In order to determine the lateral displacement and load bearing capacity of the strengthened system, a displacement control reversed cyclic loading up to 66 mm of top displacement was applied to the specimen after the pseudo-dynamic tests. Figure 10.8 shows the reverse cyclic displacement protocol for the top story of the test frame. The cyclic displacement histories applied to the first and second stories were consistent with the first modal shape of the test frame. They were determined using the method proposed by Molina et al. (1999) and Maia and Silva (1997) by taking the top story displacement protocol into consideration. 

The current trend in seismic design of dams is to conduct linear or nonlinear time-history analysis to obtain dynamic response of dam to earthquake loads. Time-history analysis of dam requires input ground motion time histories (acceleration, velocity, and displacement). 

Next, whenever diffusion is considered to proceed simultaneously along with a non-steady state loading history, such as if slow strain rate tests were simulated, the stress-field is obviously time dependent, and so, the stress dependent element matrices do, too. Besides, when large geometry changes occur, the deformed distances become the diffusion paths of interest, so that coordinates x must be continuously updated with deformation displacements, and thus, they also become time dependent. As a result, all the element matrices in equations (13) must be updated throughout the simulation histories, i.e., they... 

Figure 20.1 Idealized rheological systems, (a) A system with two parts in each part, the only behavior shown is viscous (no energy recoverable), (b) A system with two parts in each part, behavior is the sum of a viscous element and an elastic element. In both systems, the load is imposed in such a way that the displacements in the two parts are equal, (c) A possible loading history for the system in (b). (d) The loads in the two parts of the system as they would change with time. Equations and a numerical example are given in Appendix 20A.

Where Lx, Ly, and Lz are the lengths of the computational cell in the x, y and z directions respectively and Uy, Uz are the corresponding displacement components, Ci and C2 are loading controlled constants related to the velocity of the upper surface. A typical loading history is shown in Fig. 2 by plotting the velocity history of the upper surface. 

These errors can be transferred to the next step while the new displacement commands are sent to all modules by UI-SIMCOR based on the calculations from the previous step. Thus, the errors are accumulated along the load history and may lead to numerical divergence. In this study, error monitoring was applied for each step by comparing the imposed displacements and actual movements. This enables an evaluation of the stability of the model and the reliability of the results. 

At each steady load - speed combination, test rig temperatures were stabilised and the data obtained for the determination of attitude angle and eccentricity. Data reported in this paper were all obtained at a single value of steady eccentricity ratio and attitude angle. Time histories of the bearing housing horizontal and vertical displacements relative to the journal, external dynamic forces and... 

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