Three-Dimensional Dynamic Behavior of Embankment on Liquefiable Ground

In recent years, there has been serious damage to embankments on liquefied ground because of large earthquakes. To understand such damage, many two-dimensional shaking table model tests have been performed, in both gravitational and centrifugal fields, to investigate the dynamic behavior and residual displacement of embankments and river dikes on liquefiable ground. In recent years, three-dimensional numerical analysis has been used in practical design because it is difficult to consider the complex dynamic behaviors of three-dimensional embankments and the surrounding liquefied ground in a two-dimensional analysis. However, there are only a limited number of cases in which the applicability of three-dimensional analysis has been validated based on comparisons with true values derived from model tests or data from actual disasters. Therefore, in this study, a series of shaking table tests were conducted to investigate the seismic behavior of a three-dimensional embankment on liquefiable ground. In addition, the effect of the shaking direction on the seismic behavior of the embankment was evaluated. The experiment revealed that the residual deformation and its dominant direction were significantly affected by the three-dimensional shape and total weight of the embankment, not by the shaking direction. This result indicates that the influence of the three-dimensional shape of the embankment on the deformation behavior cannot be ignored, and that the influence should be properly evaluated in seismic design.

FEM Analysis as a Tool to Study the Behavior of Methacrylate Adhesive in a Full-Scale Steel-Steel Shear Joint

The use of adhesive to joint structural elements, despite many advantages of this technology, is not a method commonly used in engineering practice, especially in construction. This is mainly due to the poor recognition of the behavior, both in terms of testing and analysis, of joints made on a scale similar to the actual elements of building structures. Therefore, this paper presents the results of model tests and then numerical analyses of adhesively bonded joints made of high-strength steel elements in a full-scale (double-lap joint). In order to properly model the adhesive connection, material tests of the methacrylate adhesive were performed in the field of tensile, shear (in two versions: single lap joint test and thick adherent shear test) and bond properties. Comparison of the results of the model and numerical tests showed very good agreement in terms of the measurable values, which makes it possible to consider the results obtained in the adhesive layer as reliable (not directly measurable in model tests). In particular, the distribution of stresses inside the adhesive layer, the range of plastic zones and areas of loss of adhesion are presented and discussed. The results indicate the possibility of a reliable representation of the behavior of adhesively bonded joints of high-strength steel, thus providing a tool for the analysis of semirigid adhesive in large-size joints.

Research of model tests of parameters move-ment of the goat crane under action of load loads

The results of experimental researches of parameters of movement of the model of the gantry crane under the influence of wind loadings are resulted. The assessment of the accuracy and reliability of the obtained results is performed and further directions of research are outlined. The adopted test program included the definition of similarity criteria and scale of the model, where the main parameter was the speed of the crane when exposed to wind. The influence of various factors and assessment of the impact of their interaction was achieved by conducting PFE type 24.

ESTIMATION OF HYDRODYNAMIC COEFFICIENTS OF A NONLINEAR MANOEUVRING MATHEMATICAL MODEL WITH FREE-RUNNING SHIP MODEL TESTS

Free-running model tests have been carried out based on a scaled chemical tanker ship model, having a guidance, control and navigation system developed and implemented in LabVIEW. In order to make the modelling more flexible and physically more realistic, a modified version of Abkowitz model was introduced. During the identification process, the model’s structure is fixed and its parameters have been obtained using system identification. A global optimization algorithm has been used to search the optimum values and minimize the loss functions. In order to reduce the effect of noise in the variables, different loss functions considering the empirical errors and generalization performance have been defined and implemented in the system identification program. The hydrodynamic coefficients have been identified based on the manoeuvring test data of free-running ship model. Validations of the system identification algorithm were also carried out and the comparisons with experiments demonstrated the effectiveness of the proposed system identification method.

A STUDY ON VISCOUS ROLL DAMPING OF A BOX-SHAPED VESSEL IN THE FREQUENCY DOMAIN USING THE DISCRETE VORTEX METHOD

This paper presents a study on viscous roll damping of a floating box-shaped vessel in the frequency domain. The application of the discrete vortex method (DVM) for calculation of the viscous roll damping in regular seas has been validated by model tests. Equivalent roll RAOs associated with a range of regular wave amplitudes are calculated to assess behaviour of the viscous roll damping in relation to incident wave amplitude linearisation. A model test is conducted using the model test facilities of the Marine Hydrodynamics Laboratory at Newcastle University to validate the applicability of the DVM in calculating the roll RAO in regular waves and to study the application of this method to irregular waves. Results of these model tests are presented in this paper.