Papers by Keyword: Dynamic Load

Abstract: The derrick of a drilling ship is a kind of dynamic ocean derrick which is often applied to drilling operations for ocean engineering. Comparing with land rig derrick, the operating environment of drilling derrick is more complicated with not only the regular functions of static force but also the dynamic loads induced by wind, wave and current. Therefore, this paper takes a drilling derrick as example to make clear of the dynamic characteristics of the drilling derrick under the action of dynamic loads from outside environment with the finite element software ANSYS as tool to accomplish the modal analysis of the drilling derrick. According to the natural frequency and the vibration mode of the drilling derrick after modal analysis, the deformation response and the weak parts of the drilling derrick under different motivation can be predicted, and some improving suggestions can also be illustrated as well. This paper completed the dynamic analysis of the drilling derrick by modal analysis, and moreover, the displacement response and the stress of the drilling derrick varied with time can also be obtained. As consequence, the conclusion can be taken as reference for design of the drilling derrick, safety application and life sustainment.

Abstract: Based on the idea of system theory and highlighting the main aspects of the contradiction, the working device of mechanical excavator is simplified to fewer degrees of freedom dynamic model by analysis, and the main structures of influencing dynamic factors and wire rope are regarded as elastic bodies, other structures as rigid bodies; Starting from the theoretical dynamic characteristic curve of excavator, utilizing typical working conditions as calculation conditions, using Lagrange equation as a method to solve the dynamic integrated constraint system, we can establish the dynamic equations of working device and get the maximum dynamic load and dynamic load coefficient, and provide a reliable basis for selection of the dynamic parameter and calculation of structure strength.

Abstract: Incident frequency of wave on the intensity variation of the EME had been studied in this paper, based on failure test under dynamic load of Granite. The results show that the intensity of EME gradually attenuates with increasing of incident frequency of wave. The intensity of EME with the joint stiffness; the intensity of EME increases with viscosity coefficient; the variation of the EME with viscosity coefficient is influenced by frequency. The research outcomes are in agreement with others experimental results.

Abstract: The study of heavy vehicle forces on pavement is important for both vehicle and pavement. Indeed it was identified several factors such as environment, materials and design consideration affects pavement damage over time with traffic loads playing a key role in deterioration. Therefore, this paper presents dynamically varying tire pavement interaction load, thus enable to assess the strain response of pavements influenced by road roughness, truck suspension system, variation of axle loading and vehicle speed. A 100m pavement with good evenness was simulated to check the sensitivity of the dynamic loads and heavy truck vertical motions to the roughness. The most important performance indicators that are required in pavement distress evaluation are radial strain at the bottom of the asphalt concrete and vertical strain at the subgrade surface was predicted using peak influence function approach. The results show that truck speed is the most important variables that interact with truck suspension system and thus effect of loading time are extremely important when calculating the critical.

Abstract: The characteristics and distribution of pores in soil are the key factors in the determination of the physical and mechanical characteristics of soft soil. Using static-dynamic true triaxial test system of modified SPAX-2000 and scanning electron microscope (SEM), the microstructure images of soft clay in the Peal River Delt are studied. By analyzing these microstructure images, eight microstructure parameters including number of pore, total area, classification of area, total perimeter, average diameter, roundness, shape coefficient and anisotropy have been obtained. The changes of microstructure parameters are analyzed ,before and after applying dynamic load . The results show that the change of microstructure parameters has certain rules. This study is help to provide microscopic theory basis for static-dynamic drainage consolidation method to treatment soft ground engineering design.

Abstract: Gears play an important role in every aspect of power and motion of transmission from historical period to modern day period . Due to this , gear design has become a complicated art.A considerable amount of research has been carried out to determine the amount of dynamic gear tooth loads acting.The findings of the dynamic load between the gear teeth results in difficulty for the designer.In this paper, an effort has been made to formulate a simple design procedure for calculating the dynamic load .Earlier the stiffness characteristics and deformation of the gear tooth were studied to predict the dynamic load acting. This was developed with the tooth assumed as a short cantilever.Whereas in reality, an involute profile exists in a spur gear tooth.Based on this reality, work has been done to model the exact profile of the tooth.Later ,the stiffness characteristics were carefully analysed and an improvement was thus made. It was proved that FEA is one such technique that can be used for predicting dynamic loads acting on a gear tooth.

Abstract: Safety inspection of the bridge has become particularly important owing to a large number of aging bridges in China, in order to evaluate the safety of a bridge project that has been completed in Harbin, research methods of combining theoretical analysis, numerical simulation and field test is applied, response parameters changes under static and dynamic loads is studied emphatically in this paper.

Abstract: Shear lag effect of box girders under static, transient dynamic load and harmonic dynamic load has been studied, respectively, through finite element method. Shear lag effects under different load conditions were compared and dynamic loading influence on shear lag was analyzed. The results show that the dynamic load has great influence on shear lag of thin box girder that can not be neglected. During the research, the eyesight was transfer from the conventional static load to the dynamic load to study the shear lag problem of box girder. The research conclusions will be useful for the design and construction of bridges and will enrich the design theory of box girder.

Abstract: This paper analyzed the way that dynamic load influenced heat transfer performance of ground heat exchanger in summer conditions, taking a ground source heat pump central air conditioning project in toll stations in Shanxi Province as research subjects. Data analysis indicates that dynamic load effect on the changes of supply and return water temperature of both buried side and load side.

Abstract: This paper used LS-DYNA simulation software to simulate rock bolt breaking position, displacements at different locations and the plastic deformation under dynamic load. Major drew the following conclusions: plastic deformation of the bolt away from breaks 600mm is only 1/20 compared with breaks; deformation of the rock bolt increased as the distance away from dynamic load applied position reduced, rock bolt deformation under dynamic load has a local effect; rock bolt deformation under dynamic load and rock bolt deformation under static load had essentially different.