800 publications from this institution
Excavation of the soil is actually the unloading process. The unloading process of soil makes the soil uplift, and the soil uplift is restricted by the pit engineering piles. And then, engineering piles should bear the vertical upwards pulling force caused by soil uplift. When pulling force is huge and tensile bearing capacity of pile is low, engineering piles could be pulled apart, and it is harmful to bearing capacity and durability of engineering piles. This paper adopts the finite element method to simulate engineering piles during pit excavation, and studies the traits of engineering piles in various excavation working conditions and different position. The computational results show that the deeper pit, the bigger displacement and tensile forces of piles, and the farther away from edges of the pit, the bigger displacement and forces of piles. In addition, the paper also gives a formula about the relationship between depth of pit excavation and uplift force on piles.
With the advancement of deep learning, data-driven structural damage identification (SDI) has shown considerable development. However, collecting vibration signals related to structural damage poses certain challenges, which can undermine the accuracy of the identification results produced by data-driven SDI methods in scenarios where data is scarce. This paper introduces an innovative approach to bridge SDI in a few-shot context by integrating an adaptive simulated annealing particle swarm optimization-convolutional neural network (ASAPSO-CNN) as the foundational framework, augmented by data enhancement techniques. Firstly, three specific types of noise are introduced to augment the source signals used for training. Subsequently, the source signals and augmented signals are recombined to construct a four-dimensional matrix as the input to the CNN, while defining the damage feature vector as the output. Secondly, a CNN is constructed to establish the mapping relationship between the input and output. Then, an adaptive fitness function is proposed that simultaneously considers the accuracy of SDI, model complexity, and training efficiency. The ASAPSO is employed to adaptively optimize the hyperparameters of the CNN. The proposed method is validated on an experimental model of a three-span continuous beam. It is compared with four other data-driven methods, demonstrating good effectiveness and robustness of SDI under cases of scarce data. Finally, the effectiveness of this SDI method is validated in a real-world case of a steel truss bridge.
This research focuses on the cultural landscape of traditional village toponyms in the northern Guangdong region, aiming to reveal the spatial distribution, site selection characteristics, temporal evolution patterns, and influencing factors of toponyms. The study employs quantitative statistics and ArcGIS spatial analysis methods, combining place name classification and kernel density analysis to explore the mechanisms through which natural and human factors influence place name distribution. The main findings are as follows: (1) Traditional village toponyms exhibit a characteristic of “large dispersion and small aggregation” with high-density areas mainly concentrated in Meizhou and Qingyuan. (2) Natural toponyms dominate, showing a strong correlation with river valley and plain environments, while village location demonstrates hydrophilicity and terrain suitability. Human toponyms enrich the landscape’s connotation through cultural identity and social memory, reflecting the profound influences of Confucian agricultural education traditions and immigrant cultures. (3) Economic activities and population migrations during historical periods have significantly shaped the cultural landscape of toponyms, not only promoting the evolution of village site selection and distribution patterns but also profoundly affecting naming conventions for toponyms. This research emphasizes the importance of protecting the cultural landscape of toponyms while achieving a symbiotic relationship between cultural value and economic benefits through regional cultural tourism development, laying a theoretical foundation for the long-term preservation and sustainable development of regional cultural heritage.
Abstract To accurately obtain the frequency of voltage and current signals and form the basis for the analysis of power quality in the Transformer Terminal Unit (TTU), a Hanning window and interpolation algorithm is proposed to estimate the signal frequency. The principle of the algorithm is introduced, and the computer program is written. At the same time, the voltage signals with different frequencies are numerically generated and the real voltage is measured, and the signal frequency is estimated by using the algorithm. The results reveal that the proposed method can accurately estimate the signal frequency for TTU, and the maximum error of frequency estimation is only 2 mHz when the signal frequency varies in the range of 49.8-50.2 Hz. However, the maximum error estimated by the FFT algorithm is up to 0.2 Hz. The computation time of the Hanning window and interpolation algorithm is only 1.29 times that of the Fast Fourier Transform algorithm. The work lays the foundation for accurate and rapid estimation of voltage and current signal frequency in TTU.
Ordinary reinforced concrete (RC) and prestressed concrete bridges are two popular and typical types of short- and medium-span bridges that accounts for the vast majority of all existing bridges. The cost of maintaining, repairing or replacing degraded existing RC bridges is immense. Detecting the abnormality of RC bridges at an early stage and taking the protective measures in advance are effective ways to improve maintenance practices and reduce the maintenance cost. This study proposes a systematic method from influence line (IL) identification to damage detection with applications to RC bridges. An IL identification method which integrates the cubic B-spline function with Tikhonov regularization is first proposed based on the vehicle information and the corresponding moving vehicle induced bridge response time history. Subsequently, IL change is defined as a damage index for bridge damage detection, and information fusion technique that synthesizes ILs of multiple locations/sensors is used to improve the efficiency and accuracy of damage localization. Finally, the feasibility of the proposed systematic method is verified through experimental tests on a three-span continuous RC beam. The comparison suggests that the identified ILs can well match with the baseline ILs, and it demonstrates that the proposed IL identification method has a high accuracy and a great potential in engineering applications. Results in this case indicate that deflection ILs are superior than strain ILs for damage detection of RC beams, and the performance of damage localization can be significantly improved with the information fusion of multiple ILs.
Electrical discharge machining (EDM) is common used process in aviation industries for machining micro-hole on the blade in aeroenging.Ti-6Al-4V is widely applied in frontier for its excellent properties such as a high strength-weight ratio, great heat stability and exceptional corrosion resistance.The micro-hole plays an important role in the micro-parts. In the present study, the mathematics models have been developed for relating the responses as the tool wear ratio and white layer thickness to input parameters like pules-on time, pule-off time and discharge current in a die-sinking EDM process. The response surface methodology has been applied for developing the models using the technique of design of experiment (DOE). The experiment plan adopts the centered central composite design (CCD).The experimental and predicted values were in a good agreement.
The paper gives the introduction of the construction technique of a new-type track structure—Slab Non-ballast Track, which will be used on the bridge of Qinshen Special Railway Line for Passenger Transportation, and sheds light on a series of key construction techniques, mainly including: fabrication of the track slab, research and production of CA sand mortar, construction of concrete bearing and convex retaining wall, paving of track slab, pouring of CA sand mortar, construction of the filled cushion slab etc. All these will have the significant reference and application value for its employment to the bridge construction of the city overhead track and the express-railway.
In this paper, CMOS-compatible electrothermally and laterally driven uni-directional and bi- directional microswitches have been designed, fabricated, post-etched and tested. These types of microactuators use the inherent features available in standard CMOS process technology, to realize novel bi-directional microswitches integrated with IC components. A single post-processing etching step is used to release freestanding microswitches by a CMOS-compatible etchant, tetra-methyl ammonium hydroxide (TMAH). The input voltages of these microdevices can be less than 5 volts and compatible with CMOS operational voltages. Analytical calculations and FEM analysis have been performed to predict the performance of microswitches as a function of the design parameters.
SMA is an asphalt mixture of asphalt,fiber stabilizer,mineral powder and a small amount of fine aggregate.Because of its good sliding and anti-rutting performance,SMA pavement is widely used in anti-skid surface of high-grade highway.A detailed description on the construction characteristics of SMA pavement raw materials,mixture and impact factor analysis and construction methods are put forward in this paper,which has a certain reference value.
This paper introduces the manufacturing processes of two main components: the chord member with integral joints and the anchorage boxes. The fabrication technology of the chord member and the technique of the deformation control in the welding of the anchorage boxes are mainly described. Some new technique and new technology are summarized.
The nonlinear analysis of dog-bone steel beam was done by the finite element analysis software ANSYS.By means of analyzing the effects of the deformation of dog-bone steel beam under 7 different loading positions,the deformation regularities of dog-bone steel beam under variety of loading position were summarized systematically.
