Papers by Keyword: Waves

Abstract: Wind data is very necessary in estimating wave height at sea, especially in areas that do not yet have wave data recorded. This research aimed to determine the characteristics of waves in the western waters of Lampung, as well as compare the results of wind data simulations of the Lampung recording station with those in Bengkulu. The results of wind data processing and geographic position would determine the dominant wind direction, retrieval length, and several variables characteristic of ocean waves. The results of the analysis showed the dominant wave generation direction towards the South on the west coast, with a minimum wave height of 0.95m a maximum of 4.3m, and a wave period of up to 11 seconds. The wave broke out at a height of 1.571m depth of 1.49m according to calculations. The average wave rupture occurred at a depth of 1.49m with a wavelength of 1.571m with an average Ks value of 0.53 and an average Kr value of 0.85. The simulation results concluded that wave height using wind data from the Bengkulu recording station had a greater value than using wind data from the Lampung recording station.

Abstract: Anchors in concrete are widely used to transfer any given load combination into a concrete member. The dynamic behavior of post-installed rebar anchors has been experimentally investigated in this study. The attention was focused on anchors controlled by concrete splitting failure, the case that may occur with anchors and fastenings located close to an edge or to a corner. In this regard, Split Hopkinson Pressure Bar (SHPB) technique has been employed to test the anchorage systems under dynamic push-in loads. The effect of loading rates, concrete compressive strengths, and embedment depths on ultimate splitting load has been studied. The results showed the loading rates had a pronounced effect on the anchor ultimate loads and total absorbed energy by the anchors. Whereas the variation of concrete compressive strength influenced the ultimate load, the increase in embedment depth had no noticeable effect on ultimate load.

Abstract: This paper presents the negative effects of the vibrations produced by railway transport systems upon the constructions in the neighbourhood of the railways. The railway vehicles in motion produce very high intensity vibrations. Through the soil, these vibrations are transmitted to the foundations of the constructions in the vicinity and consequently settlements, cracks, even collapses of buildings can occur. The paper contains a theoretical part where the features of free and forced vibrations of the track/vehicle system as well as the features of the vibrations of the vehicles displacing along a joint track are described, followed by a practical part in which are shown the results of measurements made to highlight the effects upon the constructions (values of accelerations, velocities and displacements).

Abstract: Senoro Gas Development Project is one part of a joint project between Pertamina and Medco E&P in the field of oil and gas exploration, located in Central Sulawesi, Indonesia. Senoro gas field built a jetty as berthing facility with length around 500 m from the shore. Based on the survey results showed that significant wave height is 2.7 m height at jetty area, while the requirement for vessel berthing larger than 50.000DWT is 0.7 to 1.5 m. Therefore, pile breakwater was planning to build in Senoro jetty area to protect and to reduce the wave height. From bathymetry data shows that the water depth in front of the jetty is between 20-30m. In this case, breakwater conventional or rubble mound type will not be effective for this depth. Thus, pile breakwater is one of the solutions as protection structures for protecting the jetty area from wave attack. The objective of this study is to modeling the performance of pile breakwater to reduce wave height with numerical model. For this study, analysis of the performance of the breakwater is done with numerical model of computational fluid dynamic analysis. The results indicated that pile breakwater was able to reduce the wave height for safety berthing requirement.

Abstract: During the manufacturing of fabric-reinforced composite parts using a matched-die compression molding process or liquid composite molding, the fabric may experience local in-plane compressive loads that cause out-of-plane deformations. The waves that result from this outofplane motion can lead to the formation of resin rich pockets (during the infusion stage of a dry fabric) or they may be forced down into a fold by the tooling. Defects such as resin-rich pockets and folds compromise the structural integrity of the formed composite part. Therefore, it is valuable to have a simulation tool that can accurately capture the fabric bending properties and predict the locations where waves or folds are likely to occur as a result of the manufacturing process. The tool can then be used to investigate changes in the forming parameters such that the development of such defects can be mitigated. A hybrid finite element model used with a discrete mesoscopic approach captures the behavior of continuous fiber-reinforced fabrics where the fabric yarn is represented by beam elements and the shear behavior is implemented in shell elements. User-defined material subroutines describe the mechanical behavior of the beams and shells for their respective contributions to the overall fabric behavior. Simulations are used to demonstrate the ability of the modeling approach to predict the amplitude and curvature of out-of-plane waves. The simulation results are compared with experimental data to show the accuracy of the modeling. Additional models are presented to demonstrate the capability of the simulation tool to capture fabric folding.

Abstract: The paper presents the mathematical modeling of the wave energy capture process. The wave energy is transformed into torque by a device composed of multiple floating cylinders, which perform oscillating motions according to the wave parameters and to the constructive elements of a new patented device.

Abstract: Truss spar model was tested using regular waves in a wave basin and the responses in surge, heave and pitch were measured. A program was developed to determine the responses using numerical method. This program was run using the model parameters. The results are agreed well with the corresponding results obtained from the test measurements. Then this program was applied to a prototype spar simulated results were compared with the corresponding numerical results and test measurements.

Abstract: Concrete truss spar model was tested using regular waves in a wave basin andthe responses in surge, heave and pitch were measured. A program was developed to determine the responses using numerical method. This program was run using the modelparameters. The results are agreed well with thecorresponding results obtained from the test measurements. Then thisprogram was applied to a prototype sparsimulated results were compared with the corresponding numericalresults and test measurements.

Abstract: A numerical wave flume (CADMAS-SURF/2D) developed on the basis of NASA-VOF technique is used to simulate interactions between waves and maritime structures in order to verify its feasibility to maritime structure designs. Examinations and comparisons of the calculated results of wave impacts on typical maritime structures, such as caisson-type and composite breakwaters, with experimental data indicate that the numerical wave flume can be an effective computer aided design tool for the designs of coastal protection structures.

Abstract: Waves in superlattice (SL) contained inhomogeneities with anisotropic correlation properties are considered. The anisotropy of the correlation during the transition from 3D to 2D disorder is characterized by the parameter , where and are the correlation wave numbers along the axis of the SL and in the plane of the its layers, respectively ( and are the correlation radii). Dependencies of both the dynamic susceptibility and density of states at the continuous transition from the isotropic three-dimensional inhomogeneities () to the two-dimensional ones () have been obtained.