Advanced Materials Research Vols. 197-198

Abstract: This paper describes the laboratory measurement of shear interface properties between asphalt pavement and concrete bridge deck using the shear test. The main factors affecting shear strength are interface frictional resistance and adhesive stress from material of waterproof layer. Firstly, we simplify the whole system by considering the asphalt pavement as an elastic layer and the cement concrete deck a rigid base. And make a sensitivity analysis on interface contact state and the material modulus of waterproof layer. The maximum shear stress increases as interface contact state changes from continuous to smooth and as modulus of waterproof layer material decreases. Secondly, an interface shear experiment is conducted with the application of portable shear apparatus. With interface shear strength as evaluation indicator, shear strength of different interface treatments is arranged in descending order, i.e. cleaning up laitance and spreading aggregate between layers; only cleaning-up laitance; leaving the surface untreated. While the descending order for shear strength of different waterproof materials can be listed as follows: SBS modified asphalt, penetration grade of 70 asphalt. Therefore, based on the laboratory test results, it is recommended that before applying waterproof adhesive layer, laitance and dust on concrete deck surface should be cleaned up and keeping it dry. And the material for waterproof adhesive layer should be SBS modified asphalt with one-size aggregate of 4.75mm-9.5 mm spreading on.

Abstract: Hydrogen permeation and embrittlement behavior of hot-dip galvanized steels in wet-dry cyclic simulated marine atmospheric environment was investigated by hydrogen permeation current measurement using modified Devanathan-Stachurski cell, slow strain rate tensile test and scanning electron microscopy technique. It was found that hydrogen absorption was accelerated in wet-dry cyclic environment. On the other hand, hydrogen absorption and permeation reduced the percentage elongation after fracture of galvanized steel specimens; meanwhile, the fracture characteristics of samples fringe occurred some lacerated phenomena, i.e., galvanized steels show a higher susceptivity of hydrogen embrittlement when exposed to wet-dry cyclic marine atmospheric environment.

Abstract: The effects of Na₂SnO₃ and CuSnO₃ on the thermal decomposition and fire performance of wood were characterized by thermogravimetric (TG) analysis, differential thermogravimetry (DTG), and thermogravimetry–mass spectrometry (TG–MS) analysis. The addition of these chemicals caused a decrease in the decomposition temperature, a reduction in weight loss, and an increase in the amount of char produced. The results showed that ion current intensity and ion peak area of the typical representatives of incombustible ion such as m/z = 18 and 44 MS signals were increased by the flame retardants but the inflammable ion such as m/z =12, 26, 28 etc. MS signal was decreased at the meantime. What’s more, the maximum ion current intensity and ion peak area of m/z = 64 signals were increased obviously, which mean that the flame retardants can significantly enhances the dehydration and inhibits the deploymerisation of wood.

Abstract: In this paper we first review the inertial effect coefficient model for fatigue crak growth (FCG) under constant amplitude (CA) loading based on static fracture mechanics with thinking about the inertial effect coefficient and its impact to crack tip, and then discuss the relation between threshold stress intensity factor (K_th ) and fatigue crak growth rate, which is in good agreement with the result by analysing the relation between dynamical coefficient and fatigue crak growth rate. Comparison of the present analysis with experimental data taken from the literature demonstrates that threshold stress intensity factor (K_th) has a greater impact to the fatigue crack propagation.

Abstract: The way of pulse discharge strengthening is introduced, and the electromagnetic heat pulse discharge method can increase the strength and toughness of welded joints. 16Mn low alloy steel welded joints are used in the ZL-2 super pulse current generator, and the test of pulse discharge strengthening is carried out. And the mechanical performance comparison test of welded joint is finished. On the universal tensile machine, tensile strength test before and after strengthening has been done. On the S-4800 scanning electron microscope, micro-fracture morphology is analyzed. The results show that electromagnetic heat strengthening test is carried out based on the appropriate discharge parameters. In the junction of weld and base metal near the heat affected zone of the fracture, there is a white layer organization. It appears to improve the mechanical performance of welded joint, and enhance strength and toughness of welded joints.

Abstract: This paper presents the results of experimental analysis and theoretical research of piezoelectric stack actuators. The key is to understand the behavior of piezoelectric materials mechanical loads in this paper, and to determine optimum working conditions. Based on analysis of some parameters and driven model, which are necessary to performing design optimization to achieve maximum energy transfer and minimum power consume.

Abstract: By using of closed-form solution for predicting fatigue crack initiation life of a beam subjected to the transverse bending load in large range damage， fatigue crack initiation life of backup roll of four high mill is predicted. The method adopted in this paper is simple and effective. A new method is provided for predicting fatigue crack initiation life backup roll of four high mill.

Abstract: Rock rheology is common in engineering practice, which has an effect on long-term security and stability of the project. In order to understand the rheological mechanical properties under the condition of unloading sand, automatic servo apparatus of triaxial creep of rock was used to have a rheological mechanical unloading triaxial test on sandstone, which got typical flow complete curves of rock. Rheological test results showed that rheological phenomena occured in sandstone, and its rheological properties were significant with large rheological deformation, especially in high-stress conditions, When the external load exceeded the long-term strength of rock samples, specimen deformation went through three typical rheological stages with time increasing, and ultimately speed up the flow breakdown. Based on the experimental results, analyzed and studied the rheological parameters that were obtained, and discussed unsteady character law of rheological parameters. defined rheological damage of rock in the accelerating flow process as the unloading capacity and time-related exponential function, and proposed corresponding damage evolution equation, brought damage evolution equation into Burgers rheological model, and obtained nonlinear unloading model of rheological damage of rock, used accelerating rheological test curve of sandstone samples under the condition of 15MPa confining pressure and 135MPa stress level to verify nonlinear unloading model of rheological damage of rock, and the results showed that the fitting results of rheological test data and the improved rheological model had good consistency, and the rheological model can reflect the three stages of nonlinear rheology of rock, which can reflect the rheological characteristics under the condition of unloading sandstone more accurately.

Abstract: CA mortar is a key component of slab track. It is used as the material for leveling damping structure layer between the rigid track slab and concrete trackbed of slab track in high speed rail. In order to determine functions of CA mortar with low elastic modulus (EM), the beam/plate theory on elastic foundation was applied to the calculation of slab track’s stress. Under the bonding or no-bonding condition, the influence of CA mortar’s EM on the warping stress and displacement of track slab were calculated. Stress distribution of CA mortar under the common effects of train load and temperature gradient was explored, and the intensity requirement of CA mortar with different EM was put forward. Calculation results show that longitudinal and lateral bending moments of base plate both increase with the increasing of CA mortar’s EM; when the CA mortar’s EM is in the range of 50～10000MPa, there is gap between track slab and the mortar and the deformation of CA mortar (50mm thick) is not enough to compensate the warpage of the track slab; with the increasing of CA mortar’s EM, the tensile and compressive stresses of CA mortar both increase under the common effects of train load and temperature gradient, thus higher requirements on tensile and compressive strength are demanded when CA with high elastic modulus is used.

Abstract: This paper presents the oil quality evaluation system and establishes the two-stage fusion model based on multi-sensor information fusion technology. It also develops the oil quality evaluation model based on neural network model. With the advantages of multi-source information technology, the model implements comprehensive evaluation for oil quality, and provides a set of neural network training process and its results which achieve the oil quality evaluation based on information fusion. The case study shows that the prediction results for four kinds of oil samples by evaluation model based on multi-source fusion are consistent with the actual results. The comparison between operation test trend predictions and actual tests also shows the correctness of the oil quality evaluation model. The proposed multi-information fusion technology for oil quality evaluation system improves the evaluation accuracy and reduces dependence on technical personnel’s analysis experience, which is of great importance for improving the technical management level and the awareness of oil lubrication properties.