Papers by Keyword: Dynamic Load

Abstract: It is one of focus topics that metro vibration affects foundations and environments. Assumed that crumb rubber mortar can be injected into foundations to form separate vibration layerbecause crumb rubber mortar is with better ductility and properties of vibration resistance,the layer decreases the effect of transportation load on foundation. Different diameters and volumes of rubber power were joined into the mortar to form rubber mortar by experiments. Then their flow degree and strenghth were measured and compared with ordinary mortar. The result shows that the rubber with smaller diameters can improve flow properties of mortar. When the volume inserting is ten percent of total sand volume, the flow property is best. The rubber mortar with best flow property was conserved for twenty-eight days. The damp property and impact resistant were determined under metro dynamic load. The experiment found that when the volume inserting is twenty percent of total volume, the damp value was improved twenty percent with twenty-five percent of absorbing energy and better separate vibration property. Therefore, the separate vibration layer can largely reduce the effect of vibration from metro and decrease the settlement of foundations of metro.

Abstract: This paper introduces the components of central air-conditioning system and compares the advantages and disadvantages of the PID control and fuzzy control.Fuzzy control theory and inverter technology are combined to design the Energy-Saving Monitoring System based on the fuzzy control box of STM32F103C8T6,Siemens S7-200 PLC, ABB inverter as the hardware system and interfaces configuration of KingView as the software. Experimental results show that the water system can be variable flow controlled based on the dynamic load, central air-conditioning energy efficiency the COP has greatly improved under the premise of ensuring the comfort of central air-conditioning.

Abstract: The paper brings the results of a general analysis dealing with the possibility that a vehicle can be misused for an intended attack on selected transportation structures. A vehicle driving at a high speed and crashing into a bridge column intentionally was the basic analyzed scenario of the attack. Based on the analysis of the technical parameters of available vehicles we have set the values of basic parameters characterizing the vehicle crash into a bridge column. The results of the accomplished quantitative analysis can be used for evaluating the vulnerability of specific transportation structures.

Abstract: Most studies are focused on topology optimization techniques under external static loads. However, all forces are dynamic in real world. Mathematical optimization with dynamic loads is almost impossible in a large-scale problem. Thus, the bi-directional evolutionary structural optimization method (BESO) is extended to the topology optimization problem of structure under transient dynamic loading. Structural stiffness optimization is performed with the objective of reducing the mean compliance during the whole load-time history. By the dynamical analysis, the stiffness optimization model is established based on BESO method. In this method, the material volume is taken as the constraint condition, and the minimum mean compliance of structure is taken as the objective function. A cantilever under harmonic load has been taken as a numerical example to show the effectiveness of the proposed approach.

Abstract: In this paper, a dynamic load mathematic model for ship’s multifunctional cabins was developed using the “black box model” theory. The multifunctional cabins’ dynamic loads for a ship navigating in a typical Eurasian route were calculated through this mathematic model. The research results show that the air-conditioning load of cabins varies with navigation areas and sailing time significantly. Ventilation load accounts for 51.92% of the total load, while heat conduction and radiation load only account for 7.47% and 6.68%, respectively. For a same navigating area, the maximum load for different cabins is 2.648 times of the minimum load at the same time. In addition, the impact factors were analyzed by regression analysis method, and that the 91.72% of variation of the dynamic load results from the outside temperature changing

Abstract: This paper describes the harmonic current effect under static and dynamic load on 3 phase 100kVA transformer model. The methodology that used to measure a harmonic current is using power analyzer with different excitation. The experiment is conducted by changing input voltage with different flux density. A waveform can be obtained by using the data collected. 3^rd order of harmonic gives a high impact to the complex waveform. At 0.6 Tesla, 50 Hz, the 3^rd order of harmonic current under static load and dynamic load is 0.00196A and 0.26746A respectively. Therefore, both static and dynamic load were give an effect to harmonic current effect on transformer. This is because when the transformer connected to the load, more current and voltage induced in order to energize the load. Moreover, the loads itself have their own harmonic effect because of the functional mechanism.

Abstract: In this paper, the results of two experiments, focused on testing the effectiveness of a method of enhancing the seismic (dynamic) resistance of masonry columns with the use of flexible polymer adhesive, are shown. The first experiment was devoted to investigate the damping properties of a polymer working between two stiff layers, whereas the aim of the second one was to verify if the identified damping properties of the polymer can improve the dynamic behaviour of short masonry columns (prisms) strengthened by confinement made of GFRP grid bonded by the polymer adhesive. The results of the first stage of experimental investigation indicate that bonding two stiff elements with the analyzed polymer adhesive leads to the significant increase in overall damping properties. The results of the second experiment show that the GFRP grid confinement with flexible polymer adhesive is more effective than stiff epoxy and mineral adhesives.

Abstract: Vulnerability of historical city cores is an important issue for numerous countries in seismic areas such as Greece and Italy. In the literature there are a wide range of approaches to defining, modeling and measuring vulnerability. These different views originate from different concepts of the causes of a disaster. Research into vulnerability is often grounded in one of these views. In this paper we present the key factors for vulnerability modeling of historical buildings caused by dynamic loading.

Abstract: Asphalt pavements are the transport structures subjected to dynamic effect of moving vehicles. Many effects influence the real values of vehicle tire forces. Road unevenness represents the most important factor influencing the magnitudes of tire forces. Such data can be obtained by numerical or experimental way. The paper deals with the numerical simulation of moving load effect on asphalt pavements and with numerical simulation of tire forces in relation to the road unevenness.

Abstract: Cable pendulum bars need to withstand not only the gravity of ripe plug and cable but also the impact load of the shedding of ripe plug. In this paper, the cable pendulum bar was modeled and analyzed using finite element analysis by UG NX4, and stiffness strength check was carried out on cable pendulum bar. On this basis, the impact load were calculated and analyzed. The shearing stress of forced off cylinder’s block, strength of steel wire rope and the force of cable pendulum bar’s locking mechanism were checked with the shock loads, and the basic theory to design and development cable pendulum bar were provided.