Scientific paper ID 1826 : 2019/3
ANALYSIS OF TEST METHODS FOR DETERMINATING DYNAMIC CHARACTERISTICS OF CONSTRUCTION MACHINES IN REACTION WIJKSOILS AND BULK MATERIALS

Galina Petkova

In the construction and rail-building processes a great application finds the processes of cutting, breaking, compacting of soils and bulk materials. These are dynamic effects, which through a number of parameters - frequency, amplitude, pressure, force, speed of movement of the work equipment, on the one hand and grain size, humidity, connectivity, particle shape on the other, perform the working process of the construction machines. These dynamic processes are strongly influenced by the dynamic characteristics (elasticity and desipation) of soils and bulk materials.

The above dynamic characteristics are described, respectively, by coefficients of elasticity and damping (respectively the magnitude of deformations and the rate of deformation of soils and bulk materials), by which the potential and dissipative energies in the dynamic modeling of the construction work equipment are calculated.

There are different static and frequency methods based on modal analysis of systems with a single degree of freedom that have been studied to assess their applicability to bulk material properties and project capabilities.

Field standardized methods do not investigate these dynamic characteristics of soils and bulk materials that matter when interacting with construction equipment - namely the coefficients of elasticity and damping,

Laboratory standardized methods make it possible, in laboratory conditions, to determine a number of dynamic properties of soils and bulk materials. The most appropriate of this group is the dynamic amplitude test method in a resonant column, which only enables the determination of the damping factor by determining the logarithmic free-oscillation decay. The method s a relatively complex dynamic load system, creating twisting fluctuations in the resonant column, which implies high cost.

Laboratory non-standardized methods for determining the dynamic characteristics of bulk materials make it possible to determine the coefficients of elasticity (hardness) and the soil and bulk soil damping factors. The test facility for impact loads has a relatively simple construction.


Строителни машини статични и честотни методи насипни материали динамични въздействияConstruction machines bulk materials railway construction machinery dynamic effects static and frequency methodsGalina Petkova

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