Applied Mechanics and Materials Vol. 192

Abstract: After briefly introducing the characteristics and steps of the MPA method, the article adopts this method to evaluating the overall damage index. This method quantitatively explained that the infilled walls are a lateral force component, which effectively reduces the overall damage.

Abstract: In order to predict the forward slip value correctly, this article established regression model of forward slip in oval-round and round-oval pass rolling, predicted the forward slip values in ach pass in Ф12 and Ф16 round bar rolling for a factory, measured forward slip of lead rods in experimental mill using geometrical modeling method. The results showed that the model of forward slip has great practical value for proper design rolling speed, rolling schedule, thereby ensuring the continuous rolling process carried out smoothly

Abstract: In this paper, the turning process of 45# steel was simulated and analyzed based on the metal cutting finite element analysis software DEFORM-3D. The analysis result of cutting force was gained. However, due to some reasons of the software itself, there is noise data in analysis results. Thus, it’s needed to filter the data to extract useful information. The selected short-duration and steady-state cutting force data was processed with the use of six-sigma rule through mathematical statistics analysis. As a result, some bad data were rejected. Noise data was filtered out via wavelet analysis and the processed function curve of cutting force that changes with time during the whole cutting course was gained.

Abstract: In this paper, the methods of the safety evaluation for pressure vessels containing defects based on “Fitness for Service(FFS)” principle were reviewed. The latest criteria for assessment in both domestic and international fields are introduced. The paper proposes the features and creative ideas of these standards by comparing their advantages and disadvantages. Then, some new methods including the fuzzy theory, probabilistic fracture mechanics, Risk Based Inspection (RBI), Artificial Neural Networks (ANN) and expert system are put forward in current engineering evaluation. At last, the trend of future research in the pressure vessel with defects’ safety assessment is prospected

Abstract: The pooling boiling plays an important role in the operation of the passive residual heat removal heat exchanger (PRHR HX). At present, smooth tubes are still widely used as boiling element in the PRHR HX; there is great extension to improve the security and miniaturize the size of PRHR HX if the smooth tubes were replaced by porous surface tubes. In this paper, the pool boiling heat transfer characteristics of porous surface tube was researched experimentally. The result shows that the porous surface tube can enhance the pooling boiling significantly: Compared with the smooth tube, the porous surface tube can greatly reduced the time before the water reached saturation; the wall superheat decreases about 1.5°C and the boiling heat transfer coefficient increases 68% to 75%. Besides, the enhanced mechanism of the porous surface tubes is also discussed in this paper.

Abstract: Effect of hard point of the engine hood on the head injury during the vehicle-human collision was studied to improve the design of engine hood. Firstly, the current common model of the engine hood was established with three-dimensional finite element modeling software, and 20 areas were divided, also a standard head finite element model was imported, secondly, each area of the engine hood was clashed by the standard head model, then the impact on the head injure was analyzed and the hard point of the hood area was achieved, thirdly, the optimization of the inside and outside panel materials and the plate structure were carried out to reduce the head damage. The simulation results show that the engine hood after optimization gave less damage to the head, which means the research carried out here is of a good reference to the engine hood optimization design for human protection

Abstract: A suddenly pump stop in multi-pump parallel connection system could induce water hammer which may cause serious accidents. To prevent water hammer harm, comparing experiments was carried out to study the water hammer phenomenon in the lift closing check-valve adopted system and the shuttle check valve adopted system. The result indicates that, the shuttle check valve greatly cuts the peak-value produced by stop-pump water hammer impulsion, and reduces the probability of bringing a devastating water hammer accident.

Abstract: The grinding machining parameters of large-caliber aspherics ultra-precision grinding processing depend on the analysis of online profile accuracy detection data .and the detection data has the second order of non-stationary characteristic . The research of second order of non-stationary data processing technique and isolate and reduce the random error of online detection data is key technology of ensure the precision of aspheric surface grinding accuracy . This paper proposed a parallel recursive identification of improved adaptive kalman filtering method , the simulation analysis and φ500mm aspheric surface element grinding experiment proved this method can real-time process second order of non-stationary data of online detection data , isolate and reduce the random error , make a best estimate of time-varying signal, provide correction parameter of grinding process , processed aspherical face proflie accuracy≤4μm.

Abstract: Automatic classification of grain warehousing is a long-standing problem, particularly for soybean. Automatic classification of soybean brought a series of questions such as warehousing, discharging, storage and processing. To solve these problems, we analyzed the status quo of anti-grading technology and device at home and abroad, and proposed an anti-grading device that consisted of warehousing distributor and multi-channel feeding tube. We changed the traditional single-point discharge to a more coordinated discharge, and reduced the work of topping barn and the phenomenon of grain gradation. From the tests and analysis of single-tube and multi-tube inside and outside warehouse repeatedly, we confirmed the reasonable parameters, and acquired practical achievement of the anti-grading of soybean storage. It has some practical application value.