Physical Model of Drying Shrinkage of Recycled Aggregate Concrete

We prepared concretes（RC0, RC30, and RC100） with three different mixes. The poresize distribution parameters of RAC were examined by high-precision mercury intrusion method（MIM） and nuclear magnetic resonance（NMR） imaging. A capillary-bundle physical model with random-distribution pores（improved model, IM） was established according to the parameters, and dry-shrinkage strain values were calculated and verified. Results show that in all pore types, capillary pores, and gel pores have the greatest impacts on concrete shrinkage, especially for pores 2.5-50 and 50-100 nm in size. The median radii are 34.2, 31, and 34 nm for RC0, RC30, and RC100, respectively. Moreover, the internal micropore size distribution of RC0 differs from that of RC30 and RC100, and the pore descriptions of MIM and NMR are consistent both in theory and in practice. Compared with the traditional capillary-bundle model, the calculated results of IM have higher accuracy as demonstrated by experimental verifi cation.

Methodology for Optimization-OrientedComputer Simulation and Animation

The methodology for optimization-oriented computer simulation and animationis proposed. The paper considere how to implement optimization-orientedsimulation throush the simulation activities in an attempt to intesrate animatedsimulation with optimization idea. It also deals with the application of multiple-objective optimisation in simulation study. Furthermore, the principles forevaluating and obtaining the optimum design and factor level combination of asimulated system are presented with respect to the underlying rationale.Inaddition,the approach for optimication objectives driven simulation analysis isexamined .

Using Physical Model Experiments for Hazards Assessment of Rainfall-Induced Debris Landslides

Using physical simulation models, rainfall-induced landslides have been simulated under various rainfall intensities. During these simulations, we have monitored the physical and mechanical behaviors of the landslide over the slip surface at different heights of the model slopes, as well as taking the whole slope to identify its deformation and failure processes. The results show that the rainfall duration corresponding to the initiation of the debris landslide and is exponentially related to rainfall intensity. Corresponding to the three intervals of the rainfall intensity, there are three types of slope failure modes:(1) the small-slump failure at the leading edge of the slope;(2) the block-slump failure but sometimes there are large blocks sliding down;and(3) the bulk failure but sometimes there is the block-slump failure. Based on the total rainfall-lasting time and the associated proportion of failed mass volume, the early warning of debris landslide can be classified into five grades, i.e., red, orange to red, orange, yellow to orange and yellow, which correspond to the five slope failure modes, respectively.

Field-dependent nonlinear piezoelectricity:a focused review

This contribution presents a multidisciplinary review of the so-called field-dependent nonlinear piezoelectricity.It starts with an introduction that poses the literature analysis framework,through defining this operational(that is oftenmet in practice)piezoelectric field-dependent nonlinearity.Indeed,the latter is a less known phenomenon although it is inherent to stress-free actuation responses of corresponding smart materials,actuators and structures.Then,related experimental observations from piezoelectric materials,actuator devices and smart structures tests are multidisciplinary surveyed for understanding the underlying mechanisms of the encountered field-dependent nonlinearity.Next,empirical material and numerical structural modelling and simulation approaches are critically reviewed from,respectively,the constitutive and finite element analysis points of view.Summary conclusions and few future directions for research are finally provided as a closure.It is worth mentioning that,although it is concise(retains only experiments and experimentally-correlated models and simulations),this critical review covers the last three decades period which is almost the whole age of the piezoelectric materials,actuators and smart structures research field.