SIMULATION OF THE STRESS STRAINE STATE OF THE SPATIAL GALLERY OF THE CHEMICAL PRODUCTION WHICH HAS THE CORROSION DAMAGE FOR RATIONAL REINFORCEMENT

Abstract

The article deals with the solution of an important
scientific and practical problem of modeling the stressstrain
state of building structures of an industrial metal
gallery, which is part of the general technological line
of production and overloading of mineral fertilizers.
The building structures of the research object – the
transport gallery – were built on the territory of
JSC "OPP" in the Yuzhne town, Odesa region. Metal
constructions of the gallery support the constructions
of belt conveyors (transporters) and constructions of
protective cladding. Conveyors are located inside the
gallery and are designed for overloading in bulk or
in urea bags.
The article contains a detailed technical description
of the construction of the gallery, which is a spatial
rod metal structure consisting of four flat frames
(roof, walls and bottom) which rests on a system of
hinged movable and fixed supports. The bottom
level sheathed by shell with rhombic corrugation, the
cladding of the metal frame on the other three sides
is decided in the form of a corrugated board. The
article has given the typical defects and damage to
the building, discovered during the inspection. Their
systemic nature has been emphasized. The article
determines the localization of defects and the degree
of wear and tear of the main building structures of
the galleries on the basis of instrumental studies,
the technical condition. During the examination it
has been found that, as a result of the destructive
effect of moist sea air with microparticles of mineral
fertilizers suspended in it, individual structures of the
gallery have suffered significant losses from corrosion
and are in a state of emergency or unsuitable for
normal operation. Detailed finite-element models of
the stress-strain state of the gallery under the action
of a complex of static and dynamic climatic and
technological influences were developed on the basis
of the measurements and survey results.
The scientific analysis of the modeling results proved
that the gallery, as a whole, and individual, most worn
elements cannot perceive the design effects on the
structure, taking into account the normative reliability
coefficients. It has been emphasized that due to the
lack of alternative methods of overloading of urea,
the gallery cannot be completely decommissioned
during the reinforcement period. When solving
the problem, the following methods have been
used: visual inspection, measurements of structures,
determination of corrosion wear of structures by
ultrasonic method, finite-element modeling of the
stress-strain state using the CAD toolkit - SCAD
Soft, verification calculations of the metal frame
components of the gallery.
The rational method of strengthening the metal
structures of the gallery has been offered, based on the
results of the survey, modeling and strength designs,
which consists in temporarily reducing the loads
on the conveyor system (up to 50% of the design),
unloading the main defective joints of the belts, safe
installation and inclusion in the work of additional
reinforcement structures without dismantling the
existing ones damaged by corrosion. The specified
results can be extended to most similar long-span
metal technological gallery type structures due to
their structural and technological versatility.