Applied Mechanics and Materials Vols. 204-208

Abstract: One approach to limiting CO₂ emissions from oxidation of carbon-based fuels is to capture the CO₂ and store it, possibly in onshore or offshore subsurface geologic formations. From the CO₂ transportation structure perspective, a critical component of this approach is the pipeline transportation of supercritical or dense CO₂. In CCS, the pipelines undertaking a CO2 transportation task suffer various loads, the effects of which is easily aggravated due to the existence of a high working pressure (above 7.4MPa) and inner corrosion. For the application of anthropogenic CO₂ pipe transportation technique, this paper will address a LEFM-based finite element method which can evaluate fatigue life for a CO₂ transmission pipeline containing a semicircle inner defect. Specifically, a portion of welded round steel pipeline is selected as the object of our analysis. Under the inner pressure fluctuation scenarios, an FRANC2D finite element procedure is generated to simulate mode-I crack extension from a given inner edge crack, which initiates from the half circle defect,and the corresponding stress intension factors(SIFs), , and its increment, , varied with different cracking depths, are calculated and compared. Afterwards, the fatigue lives for the pipeline with the defects of different sizes are obtained by using a modified Paris formula which can analyze the influence of crack closure and stress ratio. Thus, the relation between the fatigue life of CO₂ pipelines and the dimension of the inner defect can be determined by performing the proposed fatigue crack growth analysis.

Abstract: The reliability appraisal of buildings is an indispensable part of the daily management of the existing buildings[5], we should pay more attention to it; Through the detection and appraisal of a planned, which will provide the scientific basis for technology management and safe use of buildings. This article combined the reliability appraisal of a traffic police roof damage, discussed the property and function of the structure reliability. The freon air tank of Tongxin heat preservation material factory have exploded, which in the distance of 300m away from the traffic police, produced strong shock wave, resulting in the injury of adjacent homes, accordingly, took technical appraisal of three housing of the traffic police detachment; Three homes structure component has not seen the damage caused by the explosion, at present, the structure is safety, reliable, and failed to meet the standard of dangerous building, can continue to use normally.

Abstract: The mechanical properties of C40 ordinary concrete after different temperature and time were experimentally researched. A detailed review of experimental phenomena and the influence of the significant parameters were given, and the relationship between the compressive strength and temperature and time were discussed. The experiment showed that with the exposure of temperature and time increasing, the concrete cubic compressive strength tends to decrease generally. According to the experiment results, the formula for strength-temperature-time relationship after the fire was built. According to the coupling effects of temperature and time to the compressive strength, a new fire size classification standard was established.

Abstract: It is very important for connection of between beam and column, connection safety and reliability is premise to guarantee the normal work of the whole structure. Node often bears complex stress which includes compression, bending and shear, so the study of the mechanical properties and ascertained behavior of mechanical, failure mechanism of between beam and column is very important. This paper use finite element analysis software to analyze the node of between SRC column and RC beam which exist in high-rise buildings but relatively few researches at present. Analyzed cracking load-displacement relation and studied on relation of concrete shear strain-section steel wing shear strain and crack load of joint core with different axial compression ratio, According to data of finite element analysis, this paper bring forward formula of crack resistance capacity of SRC column-RC beam joint core, At last compare theory value calculated with formula with test data, there being less error, it indicate the formula is reliable.

Abstract: A method to simulate the crack growth, according to the strain energy release rate criterion, with the virtual crack close technique, is studied. The virtual crack close technique is used to calculate the strain energy release rate. To achieve the virtual crack close technique, in the FEA software of ANSYS, COMBIN14 spring elements are adopted to set up the finite element model. Then this method to simulate the crack growth is validated by three crack growth problems. This method is a useful and accurate numerical simulation method.

Abstract: The failure modes and the shear capacity of concrete beams reinforced with FRP reinforcement were discussed through an experimental investigation, in which continuous FRP rectangular spirals were used for shear reinforcement, while ordinary deformed steel bars are used for longitudinal reinforcement. Six concrete beams reinforced with FRP spirals were tested, the main variables considered were the shear reinforcement ratios, the shear span to depth ratios and the longitudinal reinforcement ratios. Two concrete beams of equal shear capacity which reinforced with continuous steel rectangular spirals were also tested to compare the behavior of concrete beams reinforced with different materials of spirals. All beams were tested as simply supported members subjected to a three-point load, the span of the beams varied in terms of different shear span to depth ratios. The test results show that the shear capacity and shear failure modes are greatly influenced by the shear reinforcement ratios and the shear span to depth ratios, the shear resistance provided by steel spirals is higher than that provided by FRP spirals in the case of equal shear capacity of beams, which is attributed to the differences in material properties and may result in different shear failure types. Based on the experimental program, four mechanical models are derived to give more accurate predictions of the shear capacity of test beams, the calculation results of these models are compared with that of the existing shear formulas or equations for concrete beams reinforced with FRP stirrups or spirals. The rotating-angle softened truss model, the strut-and-tie model, the shear formulas derived from the truss-arch model and Zsutty equations are suggested through comparison.

Abstract: Abstract. The fatigue crack propagation life-span of the engineering structure is studied. Linear elastic fracture mechanics is applied to analyze the life-span of fatigue crack growth of specimen, which is under constant amplitude load. The software of Fatigue is used to calculate the life-span of a center crack plate steel specimen. The result show that the calculated values of the life-span are basically well with the experimental data.

Abstract: Based on the actual measured topographic data of the pit collapse occurred at Sanjiangkou in Nanjing, a generalized model of pit collapse is established. With this model, the experimental study of flow pattern changes is made with the schemes of crow of a tree and tetrahedron-like penetrating frames. The study shows that the scheme with crow of tree play greater effect in pit velocity reduction, so it can be used in emergency rescue project. Although tetrahedron-like penetrating frames can also reduce velocity, but too crowded arrangement make limited effect in reducing velocity, therefore tetrahedron-like penetrating frames should keep proper distance while dumping into the pit collapse. Moreover, a comparative experiment is made on the effects between the singe project (only arranging the project in the slide pit) and the combined project (contains collapse entrance project and inside project). The study experiment shows that the combined project has no obvious better effect than the single project.

Abstract: Apply large general-purpose finite element analysis software ABAQUS as a platform, The criterion of iteration non-convergence conventionally used for assessing the instability state of slopes,and an example is given to the following conclusions: The strength reduction method based on ABAQUS simulate anti-slide pile slope stability analysis that has a true reflection of the elastic-plastic deformation in geotechnical engineering,it can be widely used in elastic-plastic deformation problems in geotechnical engineering. The anti-slide pile can effectively improve the stability of slopes, setting up anti-slide pile egitimately in the soil plays an important role at the safety of slope stability.

Abstract: The embankments built on expansive soil foundation with a transverse are prone to crack and slide failure. In this paper, the embankment in a certain section of Bailong highway destroyed due to cracks and rainfall. A group of steel piles and reinforced concrete beams is used to strengthen the toe of slopes, and steel piles and reinforced concrete framework beams is utilized to strengthen embankment slopes, then pressure chemical grouting is used to reinforce soil. The treatment effect is good.