Applied Mechanics and Materials Vols. 99-100

Abstract: This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable: Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement; Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage; From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviate the impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.

Abstract: High-performance concrete was made with fly ash and polypropylene fiber, the study shows that when fly ash content was 20% and polypropylene fiber was 0.6~1.2kg/m3, it had no significant influence on the workability of concrete, however the changes of 28d compressive strength and drying shrinkage of concrete are within 10%, but it can reduce brittle and improve toughness, and impact resistance of concrete is improved obviously, when polypropylene fiber content was 0.9kg/m3, it can improve over three times.

Abstract: In this article we collected bentonite samples from cities including Weifang, Laiyang and Laixi in Shandong province of China and tested their cation exchange capacity (CEC) . Orthogonal tests were designed to optimize the process parameters on acid activation. There are three quality indexes including activation degree(AD), bleaching capacity(BC) and decolorization ratio(DR) in the tests. Correlation between CEC and three quality indexes, CEC and activation strength were studied, as well as the correlation among the three quality indexes. The results show that AD and DR decrease with CEC’s diminution, while BC has no regular change with CEC’s decrease. In order to get large value of the three quality indexes, the activation strength needs increase along with the CEC’s diminution.We also find that the correlation among the three quality indexes vary with CEC. Judging by CEC, their correlation and the least energy consuming, activated clay of the best property and the various application can be prepared.

Abstract: Composite modified asphalts with nano calcium carbonate (nano CaCO3)/ SBS and nano montmorillonite (nano MMT)/SBS were prepared respectively by melt blending. Rolling thin film oven test (RTFOT) was carried out to study the aging properties. The results demonstrate that CaCO3/SBS and MMT/SBS homogeneously disperse in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Effects of the nano CaCO3 and nano MMT on the properties of SBS modified asphalt appear as a decreasing penetration, an increasing softening point, and a decreasing ductility. The anti-aging property of the nano MMT/SBS modified asphalt was better than that of the CaCO3/SBS modified asphalt and SBS modified asphalt.

Abstract: It is serious problem of the deficiency of high quality embankment filling in the expressway construction in shanghai, the Yangtze estuary fine sand has been extensive applied as the substitute filling material to avoid destroying the cultivated land and cropland. It is signality of the fine sand filling embankment technique popularization and application to the improvement of highway construction level, the protection of the cultivated land and the protection of the eco-environment. For the natural sand is no-viscous bulk solid material with great variation on mechanical properties to traditional embankment filling, now there are some problems on the application of fine sand filling embankment engineering haven’t been analyzed such as the highway performance of fine sand filling embankment. In the paper, it analyzed the fine sand filling embankment stability by considering with the shape of landslide and safety factor by using the combination method of the strength reduction method and Fast Lagrange method. The analysis included geometrical and material properties of the slope ratio, the subgrade height, the presence or absence of the surrounding soil and the thickness of it, the top seal coat, pavement structure etc. and proposed the design suggestions of the optimum fine sand filling embankment based on the analysis above[5].

Abstract: To achieve national five climate partition 3 Step in building energy-saving target of 65% by a single product realization, it is to say that wall material realize the heat preservation. The iInsulation heat preservation problem , durability , fire prevention and frame beam-column parts with cold Bridges must be solve of wall materials products . This paper introduces the material composition, structure characteristics, product performance, technical and the engineering application supporting technology on non-bearing wall material of thermal insulation and durable fire integration —break hot energy-saving composite block. And the new wall materials about the development of a technical ideas are introduced at the same time.

Abstract: The crystallization kinetics of Cu47.5Zr47.5Al5 BMG was studied by differential scanning calorimetry (DSC) using the mode of continuous heating and isothermal annealing. It is found that Tg, Tx, and Tp, display a dependence on the heating rate in the case of continuous heating. The activation energies, Eg, Ex and Tp determined by the Kissinger method, yield 445, 264 and 285 kJ/mol, respectively. The local activation energy, E(x), was determined by the Doyle-Ozawa method, which gives the average activation energy 204 kJ/mol. On the other hand, the isothermal kinetics was modeled by the Johnson-Mehl-Avrami (JMA) equation, the Avrami exponent versus crystallization fraction was calculated at different temperatures. Details of nucleation and growth behaviors are discussed in terms of the local Avrami exponent and local activation energy during the isothermal crystallization. X-ray shows that the quenched BMG only includes the glass single phase. The BMG heated to 873 K has the precipitation of the body-center cubic (BCC) CuZr.

Abstract: The nonlinear dynamics are studied for a supported cylinder subjected to axial flow. A nonlinear model is presented for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are the quadratic viscous force and the structural nonlinear force induced by the lateral motions of the cylinder. Using two-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain the flutter instability found in the experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the new equilibrium (the buckled configuration) becomes unstable at higher flow leading to post-divergence flutter. The effect of the friction drag coefficients on the behavior of the system is investigated.

Abstract: The Southern source water carries such characteristics as high algae, low turbidity and micro-polluted. In order to make flotation better applied to the source water, the following factors are researched to find out the influence on the flotation from type and dosage of coagulant, dissol- ved air pressure, air inflow. Aluminum sulphate, ferric chloride, poly aluminum chloride (PAC) are selected. With less PAC, scum generated less, the coagulant dose is 1.25mg/L.Dissolved gas pressure is directly related to bubble size.When the pressure is greater than 0.42Mpa,the effluent quality deteriorates as the pressure increases.The volume of inflow gas into the raw water is related to turbidity and capacity.The higher the turbidity of the water is, the greater the capacity will be, so the higher feed rate can be chosen.

Abstract: Pipelines are regarded as the most cost-effective and the safest choice for transporting oil in bulk. In this study, the significance and necessity of conducting damage detection for onshore pipelines is firstly stated. Then, the limitations of current measures in use in pipeline industry and the inherent difficulty of applying vibration-based damage detection techniques (VBDT) to pipeline structures are addressed. This study focuses on exploring the applicability of an advanced VBDT method, HHT method, to the condition assessment of onshore pipelines. The feasibility and effectiveness of HHT method is verified through numerical study. The result shows that for the cases with single or multi segments of damage which are of the same type or of different types coexist in the structure, the HHT method is capable of providing very good results for the damage detection of pipeline system under ambient excitations. The obtained Hilbert spectrum gives very explicit presentation of the structural response’s energy distribution in both time and frequency domain, the marginal spectrum offers satisfactory result not only for locating the damaged area but also for a rough estimate of damage severity.