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The differences of growth and root absorption of three apple rootstock seedlings was compared and the absorption of hydrogen ions and endogenous hormone levels under the replant stress was discussed in this study. Experimental results showed that the dry matter ofM. sieversiiseedlings was significantly decreased under replant stress and the root-shoot ratio was increased. Root biomass of three rootstocks increased observably and the total root length was extended by 1.45 times, 2.22 times, 1.71 times, respectively compared to control. Root activity of three rootstocks all decreased, which one ofM. hupehensisfell less than another two rootstocks. The flux direction of H+had no change forM.HupehensisandM.Hupehensis, which ofM.prunifoliachanged into outward from inward. The endogenous hormone level of three rootstocks in replant stress was affected. ABA content is higher than that of controls, IAA and ZR contents were lower than controls, GA inM. HupehensisandM. prunifoliawas higher than that of controls besidesM. Sieversii. The root amount of three rootstocks increased significantly. The dry matter accumulation, absorption of H+and endogenous hormone levels was affected and the sequence decreasingly wasM.Hupehensis,M. prunifoliaandM.Sieversiiaccording to the degree of tolerance to replant stress.

In a certain vehicle of Dongfeng Passenger Vehicle Company (DFPV), a new design of integrated hot stamping B-pillar reinforcement panel is introduced to replace the original design of two cold stamping parts connecting by spot-weld. A further light-weight design by thickness thinning is also attempted. All the schemes are validated by hot stamping process simulation and vehicle side impact simulation. The results show that by using hot-stamping steel of the same thickness as the original design, the performance of anti-vehicle side impact is improved; and an equivalent anti-side impact performance can be achieved by appropriate thickness reduction, while the weight of the part is lightened.

In order to study the influence of ultraviolet aging on the performance of different asphalt, we select two kinds of matrix asphalts of the same symbol and two kinds of modified asphalts of the same brand which are used widely in our country. After ultraviolet aging in different time, we use the samples to do the experiments of three indicators and DSR. The results show that the data of the modified asphalts after ultraviolet aging is more stable. Under the irradiation of ultraviolet light,the performance of modified asphalt is more stable.

Combining level set image segmentation with the prior shape information, we proposed an improved prior shape model in face recognition. Firstly, we introduced a local tensile invariant to X and Y direction and a shear invariant based on the shape statistics. Then, shape energy term with rotation, scale, shear and translation invariance was reconstructed in level set C-V model. The new model considers global and local image change and makes face contour evolving stably. Experimental results demonstrate that our model can segment obscured face images effectively.

To research the effect of electromagnetic stirring process parameters on the parts’ quality in semi-solid forming of aluminum alloy, the material of ZL017 was heated and melted, and electromagnetic stirred under different frequency and power, then material microstructure gained by different process parameters was observed. The elementary alteration rule of fluid field was analyzed with the alteration of stirring frequency, current density, stirring time，stirring temperature and fluid viscosity. Suitable process parameters for electromagnetic stirring of ZLl07 was concluded.

In the automotive industry, the hot forming of high strength steels offers the possibility to obtain significant reduction of weight without affecting the structural performances of final products. Compared with conventional sheet metal forming, the proper design of hot stamping process chain requires the deep knowledge of both interface phenomena and material behavior at high temperatures in order to obtain the desired properties of final products in terms of microstructure and strength characteristics. The work presented in this paper aims at accurately evaluate the effect of heating parameters on the properties of final sheet components produced in hot forming operations. Different from that in the lab, all the samples and parts used for the experimental test were produced in the production line, which can objectively show the manufacturing properties and microstructure character of products in mass. Microstructure evaluation, hardness measurement and dimensional accuracy test after hot stamping were performed and considered. The best heating parameters for the researched hot stamping B-Pillar’s production were obtained through the above research.

To research the problem of part’s dimensional accuracy error easily occurred in hot press forming, a B-Pillar on one domestic car was set as example, the dimensional of the actual part and its model diagram were compared by means of ATOS optical scanner. By recording the the process parameters used in practical production, the effect trend of three key process parameters on part’s dimensional accuracy was summarized, process parameters suitable for practical production were gained.

Traditional IF steel is Ti-IF steel for low cost. Some car producer require IF steel to have good mechanical properties with low delta r (plastic stain ratio) value (△r) as well as high performance after welding. A new IF steel was developed by adjusting amount of Nb and Ti based on Ti-IF steel and employing suitable parameters in manufacturing processes. Annealing experiments were made to decide reasonable annealing temperature. The final products exhibit good isotropy with △r ≤0.3. This new type IF steel also had good performances after welding by analyzing results of some key parameters, which can totally meet requirement of car producer.

The idea of generalized stress increment testing method which contains both the stress free method and the stress superimposing method for the residual stress determination is developed. The research development of full and partial stress free testing methods is reviewed. Different testing methods are characterized according to the different working conditions. The stress superimposing testing method of residual stress is different from the stress free one. A new stress field is introduced adding on the initial state. The residual stress is indentified by the strain increment differences of the material detected in the stress superimposing process. The traditional stress superimposing testing method including hardness and indentation method are reviewed. The principal and application of two new type of stress superimposing testing methods of residual stress are introduced, their disadvantages are also indicated.

The relationship of pre-stressed concrete (PSC) beam natural frequency and pre-stressed force is difficult to described accurately with mechanical model. The past experimental data are collected. Then five unbonded post-tensioned PSC beams are designed. Frequencies and damps are collected in the dynamic experiment of five PSC beams. Radial basis function neural network is constructed to identify the natural frequencies of prestressed beam with different levels prestressing force based on previous test data and new dynamic test beam data. Then the input and output node numbers of neural network are selected and the appropriate training algorithm and expansion coefficient is determined. In order to verify that the network performance, one prestressed concrete beam test data are left to simulation test. Simulation results show that the radial basis function neural network is feasibility to recognize the frequency of PSC beams.

To conclude the mechanics of fine blanking, the numerical simulation model of a cam’s fine blanking process was established, the forming process was simulated by DEFORM-3D software, the deform principle was summarized. Then the effect of three key processing parameters such as gap between punch and die, pressure-pad-force/counter force, serrated ring postion to fine blanking quality were researched, optimized parameters in fine blanking were gained.

To solve the problem of part’s section thinning easily occurred in hot press forming, the numerical simulation model of hot press forming process of a B-Pillar on one domestic car was established, the forming process was simulated by PAM-STAMP 2G software, the area thinning on the part were forecasted. Then through modifying the corner radius and the tiny shape of the part, the thinning level lightened greatly, the effect was certificated by new simulation results and practical production.

Along with the improvement of surface defect and decarburizing problem, the non-metallic inclusion becomes one of the most important factors which influence the fatigue performance evaluation of metallic material. To quantitatively study this problem, two group of high strength transmission shaft steel with different inclusion level are selected to do the comparison fatigue test using stair case method. Experimental data shows that the inclusion of the metallic material will observably affect its fatigue performance. The comparative large size of Al2O3 inclusions with tip edge angle was found by stereo-scan and energy spectrum analysis, which were the sources of micro crack and lead the final fracture.

Two interstitial-free steel grades, one based on combined niobium and titanium additions and the other based on titanium only addition, were investigated. Annealing experiments were used to study the effect of niobium on the mechanical property. And tensile-shear fatigue tests were used to study the effect of niobium on the fatigue property of spot welding. The experimental results show that niobium addition not only can significantly improve the mechanical properties of the basic materials by way of grain refinement, but also has beneficial effects to the fatigue strength of spot welding.

This paper presents an optimization method for optimal engineering structure design. An interface procedure is essentially developed to combine the intelligent optimization algorithm and computer aided engineering (CAE) code. An optimization example is carried out to minimize the interlaminar normal stress of a laminate which affect the delamination failure of a laminate via arranging the stacking sequence. The analytical solution is calculated to validate the accuracy of optimization results.

This paper presents a novel approach to detect the fault categories for rolling element bearings based on the continuous wavelet transform and hidden Markov models. With the Morlet wavelet transform, the effective fault information is extracted from the time-frequency domain of the vibration signals. Then, the wavelet coefficients are divided into multi-segments, and the infinity-norms of each segment is applied as the features to construct the observation vector of the hidden Markov models. Finally, the experimental results on bearing faults identification and isolation are illustrated.

The stress superimposing testing method of residual stress is different from the stress releasing way. A new stress field is introduced adding on the initial state. The residual stress is indentified by the strain increment differences of the material detected in the stress superimposing process. The traditional stress superimposing testing method including hardness and indentation method are reviewed. The principle and application of two new type of stress superimposing testing methods of residual stress are introduced, their disadvantages are also indicated.

Nonlinear properties of materials will be automatically ignored while structural dynamic analysis in ANSYS. And the energy method principle is used to analyze. So it can not be used to calculate the frequencies and modals of prestressed concrete structures directly. Accordingly, prestressing force applied to beam with initial strain method in ANSYS calculate in this paper. The perstressing force influence of the beam is changed to the impact of element materials elastic modulus. Analyze the frequencies and modals of prestressed concrete beams with ANSYS computational procedure by modified ANSYS model. The calculated natural frequencies at all levels prestessing force fit close with the experimental results. It shows that modified ANSYS finite element analysis model is feasible.