Numerical Performance of Energy Dissipation Slotted Plate for Bridge Unseating Prevention

Recently, the bridge unseating prevention devices are widely used in active seismic zones. These devices are stiffness dependant, velocity dependant and energy dissipation devices. The energy dissipation devices are designed to overcome the energy that transfers from bridge substructure to superstructure. However, the current devices are not controlled to function with different ground motion intensities and should be replaced after yielding. Therefore, this research introduced a slotted plate energy dissipation device with three parts, each part function in known deformation range. The slotted plate behavior has been evaluated numerically by finite element method. Displacement control and load control analysis has been done, and then the effect of steel grade is studied to predict the suitable steel properties for designing the plate. Moreover, the slotted plate behavior is applied in 3D bridge seismic analysis to assess the multi-level performance and the ability to overcome the seismic effect on the bridge in longitudinal direction. The results approved the capability of the plate to dissipate energy in multi-stage of deformation. The lower steel grade is suitable for low to moderate earthquake zone and the high grade can be used in severe ground motion areas. Furthermore, the bridge longitudinal behavior has enhanced with different steel grades of the slotted plate.

Phosphating Modification with Metal Ions of Carbon Steel Surface to Improve the Influence of Anticorrosion Properties

The purpose of this research is to investigate the influence of the phosphatizing process with Ni2+, Ce3+, and Ti2+ ions on the properties of the coating to obtain better corrosion protection of the metal. Steel corrosion occurs through physicochemical interaction between the metal and its surrounding environment. This leads to a change in the metal’s physical, mechanical, and optical properties that can cause damage to the functionality of the metal, which in turn may result in accidents or other malfunctions. Carbon steel grade has limited resistance to corrosion, depending on the carbon content and alloying element, the microstructure, and the surrounding environment of the material. This paper present tests that have been carried out on some of the physicochemical properties of protective epoxy and polyurethane coating on carbon steel grade. Coatings represent one of the methods available to protect metal surfaces from corrosion. Coating properties such as thickness, hardness, and adhesion were investigated. The same properties were tested by exposing the sample plates to corrosive conditions of the humid chamber and seawater. Their anticorrosion properties were explored by electrochemical impedance spectroscopy (EIS) techniques under immersion in 3.5 wt.% NaCl solutions as a corrosive medium. Part of the samples prior to application of the coatingwere modified with a phosphate solution containing metal ions: Ni2+, Ce3+, and Ti2+ to further investigate the effects of phosphatization on the properties of the coating. After exposure of the plates to the salt and moist chamber conditions, no traces of corrosion products, cracking or peeling of the coating were found on the surfaces. The adhesion properties were tested by the pull-off adhesion test. It was found that metal/polymer adhesion was satisfied according to EN ISO 4624:2016 and had the same value for all samples. However, a detailed EIS analysis showed a higher resistance of phosphate samples with Ce3+ ions than samples that were phosphated with Ni2+ and Ti2+ ions and those that did not have a sparingly soluble phosphate salt layer.

PRECIPITATION OF CALCIUM PHOSPHATES FROM A MODEL BLOOD PLASMA SOLUTION ON STEEL GRADE 12X18N10T

В работе представлено исследование процессов осаждения минеральноорганических образований в модельном растворе плазмы крови в присутствии добавок альбумина, глицина, глюкозы, глутаминовой и молочной кислот. Методом рентгенофлуоресцентного анализа изучен фазовый состав образцов. Для измерения площади покрытия образца модифицированным фосфатом кальция были сделаны фотографии. На фотографиях были выделены области покрытия твердой фазой и с помощью программы ToupView произведен расчет степени покрытия образцов стали. Осаждение кристаллической фазы происходит на всех исследуемых образцах. Отличия заключаются в распределении кристаллов по поверхности пластины. Добавка альбумин ингибирует процесс осаждения гидроксилапатита на исследуемых образцах. Показано, что добавки глюкозы, глутаминовой и молочной кислот катализируют процесс осаждения гидроксилапатита на поверхности стального образца. В процентном соотношении, от общей площади фотографии, наибольшее количество осажденного порошка гидроксилапатита наблюдается у образцов с добавлением глюкозы. The paper presents a study of the processes of precipitation of mineral-organic formations in a model solution of blood plasma in the presence of additives of albumin, glycine, glucose, glutamic and lactic acids. The phase composition of the samples was studied by the X-ray diffraction analysis. Photos were taken to measure the surface area of the sample with modified calcium phosphate. The solid phase coating areas were highlighted in the photos and the degree of coating of steel samples was calculated using the ToupView software. The deposition of the crystal phase occurs on all the studied samples. The differences are in the distribution of crystals on the surface of the plate. The additive albumin inhibits the deposition of hydroxyapatite on the studied samples. It is shown, that additions of glucose, glutamic and lactic acids catalyze the process of hydroxylapatite deposition on the surface of a steel sample. As a percentage of the total area of the image, the largest amount of precipitated hydroxylapatite powder is observed in samples with the addition of glucose.

BEHAVIOR OF STEEL PLATE-CONCRETE COMPOSITE SHEAR WALL UNDER CYCLIC LOADING

Steel-Concrete composite shear wall has become popular recently as it compensates for the disadvantages of concrete and steel plate shear walls and combine the advantage of both. However, there is no detail study that identifies the most critical parameters. This study aims at investigation of steel plate-concrete composite shear wall behavior under cyclic loading with variables such as concrete strength, grade of steel plate, total number of tie constraints and thickness of steel plate. ABAQUS/Standard is used for numerical modeling in this study. As the concrete strength decreases from 86.1Mpa to 45Mpa, the load capacity declined by 11.76% and higher stiffness was recorded in specimen with higher grade of concrete. The ductility factor is inversely proportional to grade of concrete from 86.1Mpa to 60Mpa which increases from 4.26 to 4.68 and the ductility factor of specimen with 45Mpa strength is recorded as 3.81. The energy dissipation capacity is directly proportional to the grade of concrete used. Using high grade steel plate increases the lateral load capacity significantly and exhibited more ductile behavior. Specimen with S355 steel grade exhibited 14.01% increment of the average load capacity while the specimen with S245 steel grade has shown reduction by 9.21%. Similarly, the ductility factor and energy dissipation capacity of specimen with variable grade of steel are directly proportional. Reduction of tie constraints has no significant effect on the behavior in this study due to high confinement effect of concrete by surrounding steel plate. Specimens with thicker steel plate exhibited good energy dissipation capacity.

Investigation of consequences of violation of technology of manufacture of individ-ual elements of BMP-2 track tape

The operation of the BMP-2 infantry fighting vehicle was accompanied by periodic failures of the tracked belts. This is due to the breakage of the fixing bolts of the track pins fastening bracket, and thus the military equipment became stationary. Establishing the causes of the destruction of the bolt fixing the staple of the track fingers of the tracked belt of military equipment was carried out using a complex of instrumental materials science research. In particular, the chemical composition of the material from which the bolts and staples were made was determined by the spectral analysis; the fracture surface of the fixing bolt was investigated by the macroanalysis; the microstructure of the bolts was examined using optical microscopy; the microhardness and density of the bolt material was measured. The bolts were made from steel grades 30XM and 33XC, and not from the recommended steel grade 38XC. The macrostructure of the broken bolt corresponds to the shearing structure. The microstructure showed rolling and heat treatment defects. Density measurement confirmed the presence of heat treatment defects. The imperfection of the applied heat treatment was confirmed by measuring the microhardness. A complex of metallurgical research has established the main cause of the destruction of the bolts. It consists in an unsuccessful design of bolts and brackets, an incorrectly selected steel grade with defects in rolling and heat treatment.

A Study on the smelting process of low carbon steel scrap and sponge iron in medium frequency induction furnace for production of front bumper beams

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

OUTOKUMPU MODA 430/4016

OUTOKUMPU MODA 430/4016 is a 16% chromium ferritic stainless steel that combines good mechanical properties with good corrosion resistance and heat and oxidation resistance up to 815 °C (1500 °F). It is the most commonly used ferritic stainless steel grade and can be used to replace type 304 austenitic stainless steel in certain applications. It is best suited for mildly corrosive environments. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1340. Producer or source: Outokumpu Oyj.