Complex systems typically use analytical methods and experimental methods for dynamic load resistance design. Dynamic load resistance analysis design loads are usually obtained through dynamic analysis methods, while experiments are conducted using testing machines based on the weight of the equipment to evaluate its performance. However, there is currently a lack of research on the relationship between analytical loads and experimental loads, leading to an unclear consistency between the results of the two methods. This paper investigates the structure and working principles of dynamic testing devices, as well as the dynamic action process, establishing simulation models and dynamic process simulation methods. The aim is to establish a quantitative relationship between dynamic load resistance analysis design loads and experimental loads, and to develop a digital method for dynamic testing that matches the dynamic design loads.

Combined with the characteristics of traditional vibration control methods, this paper proposes an optimization method of pipe vibration control based on vibration damping mass. Through the establishment of the pipeline vibration control strategy, a vibration damping mass structure is designed to realize the limit vibration, and the optimal control of the output energy of the pipeline system at the support position is realized. The method can be used in the optimization of pipeline vibration control, and support some engineering applications. When installing damping masses on a single straight pipe, the installation position and number of damping masses are not sensitive to the vibration energy output of the pipeline system. It is recommended not to consider the above independent variables in the optimization process. This study is basically feasible in engineering applications, providing more design strategies and technical means for vibration control of existing pipeline systems without introducing excessive safety risks and costs.

In this paper, the flow field characteristics of typical turbulent parts in the pipeline system are analyzed and studied, and the model simplification, meshing and flow field analysis methods in the flow field characteristics analysis are studied. 1) After 4 revolutions of the transient calculation of the centrifugal pump, there will be an obvious periodic signal; 2) The streamline distribution in the centrifugal pump is smooth, and there is no very obvious flow separation in the impeller flow channel and volute flow channel. The direct collision between the high-speed fluid at the outlet of the impeller and the vortex tongue causes the flow to stagnate, resulting in a local pressure rise; 3) The velocity vector distribution in the gap between the volute and the cover plate shows that there is a high-speed vortex flow inside the volute, but the velocity in the gap between the cover plate is relatively small, and there is no strong flow separation. The unsteady excitation of the anti-vibration may be related to the unsteady vortex flow, and the vortex generated in the centrifugal pump are mainly distributed near the blade outlet, followed by the leading edge of the blade and near the worm tongue. The results of velocity vector results and the distribution of physical quantities such as vortex show that the flow-induced vibration of the responsible body mainly comes from the volute wall; 4) The internal velocity distribution of the valve under uniform incoming flow condition shows that the fluctuation in the pipe is small. Therefore, the strength of the flow of valve components may not be obvious under the condition of uniform flow.

In the process of structural stress analysis and evaluation of the reactor structure, a variety of load conditions need to be considered. Among the various components of the reactor structure, the load condition of the reactor pressure vessel (RPV) nozzle is special. The reason is that one end of the nozzle is connected to the RPV barrel and the other end is connected to the main pipeline. Considering the shock load, it is currently difficult to analyze and evaluate the stress of the RPV nozzle. Due to the heavy weight of the reactor structure, it is difficult to carry out a full-scale model shock verification test. At present, the shock assessment test and stress analysis evaluation of the reactor structure follow different national standards, which leads to the phenomenon that some equipment can pass the shock assessment test but the numerical calculation stress analysis assessment is difficult to pass the specification requirements. The connection between the two evaluation methods needs to further study. Therefore, this paper uses the scaling criterion to design a scale test device for the RPV nozzle. By adjusting the length of the pipeline, the nozzles dominated by bending stress and shear stress can be studied respectively, and the numerical simulation of dynamic responses of the scaling device under high temperature and high pressure is carried out. The deformation and stress of the RPV nozzle under the impact load of the drop weight are obtained. The verification results show that the structural strength of the scaling model meets the test requirements, and it can provide a device for subsequent impact damage tests.

It's important to choose suitable method to simulate the vibration reduction of the isolators. For a long time, scholars and engineers have been working hard to reduce the error between numerical simulation and experimental results of the vibration level drop of the isolators. Due to the standing wave effect and the limitations of analytical models, it is difficult to simulate the vibration level drop of isolators well solely based on dynamic stiffness or damping. In this paper, an analysis model for the vibration reduction effect of metal-rubber (MR) vibration isolators based on impedance test data is established. The origin impedance and cross point impedance data is tested on the testing platform. The four-terminal parameter method is applied to calculate the stiffness and damping value of the MR vibration isolators. The calculation results show that compared with commonly used numerical simulation methods in the past, the model based on frequency dependent stiffness and damping can further reduce the error between the numerical simulation and the experimental results.

In practical engineering, the vibration transmission between bolted structures supported by cantilever beams involves many factors. The vibration transmission effect is the embodiment of the coupling of various factors, so it is impossible to accurately and quantitatively evaluate the influence degree of various factors. In this paper, the influence factors of vibration between bolted plates in the form of cantilever beam are studied by numerical calculation method. The effects of friction coefficient, bolt preload, temperature and pressure on vibration characteristics are studied. Finally, the contribution of different influencing factors to vibration transmission is given.

The reactor system has a large scale of components. And the system dynamic analysis model for loss of coolant accidents (LOCA) contains many non-linear factors. The transient calculation analysis takes a long time and the convergence is difficult to guarantee. In this paper, two different analysis models (complete three-loop model and single-loop model) of the first loop system of reactor are established for comparative analysis. The analysis shows that the calculation error of the main position load in the two different model is within 10%. The decoupling influence of the wave tube and the reactor inlet and outlet on the system dynamic characteristics is within an acceptable range. When the single loop model is used, it is necessary to decouple the reactor pressure vessel and pressurizer. And the simplified boundary is adapted to simulate its effect on the whole loop. The single-loop dynamic analysis model based on the decoupling criterion can greatly reduce the calculation scale and meet the calculation accuracy, which can be used to calculate the LOCA dynamic characteristics of the reactor system quickly. The model can also be used for seismic analysis of reactor system. And using this model for reactor system dynamic analysis can greatly improve the calculation efficiency. Please copy you summary here.

In practical engineering, the vibration transmission between bolted structures supported by cantilever beams involves many factors, including the friction between plates and the bolt connection relationship. The vibration transmission effect is the embodiment of the coupling of various factors, so it is impossible to accurately and quantitatively evaluate the influence degree of various factors. In this paper, the influence factors of vibration between bolted plates in the form of cantilever beam are studied by numerical calculation method. The effects of friction coefficient, bolt preload, temperature and internal and external pressure on vibration characteristics are studied. Finally, the contribution of different influencing factors to vibration transmission is given. The preliminary research shows that the bolt connects the two plates into a whole structure, and its stiffness changes little with the friction coefficient, bolt preload, temperature and internal and external pressure. The natural frequency of each order increases with the increase of friction coefficient, bolt preload and internal and external pressure, decreases with the increase of temperature, and the overall trend changes little. At the same time, the bolt preload is verified by test, the difference of natural frequency under the same preload is compared and analyzed, the numerical calculation is compared with the test value, and the vibration contribution of preload is verified.

三维编织复合材料因其优异的力学性能而得到广泛应用,对其力学性能的研究也取得一些成果.综述了近些年国内外对三维编织复合材料力学性能的研究进展,主要包含试验研究、理论研究,总结了目前研究存在的问题,并对未来的研究趋势做出了展望.

The vortex shedding phenomenon of the three-way pipe is the main excitation source for pipe vibration, which can lead to the acoustic resonance. In this paper, the vortex shedding phenomenon under the water medium of the three-way closed branch pipe is studied. The test device of a three-way branch pipe with one branch closed is established to verify the mechanism. The PIV measurement method is used to obtain the change characteristics of the flow streamline and velocity distribution of the closed branch pipe under different working conditions. Tests have shown that due to the special structure of the three-way branch pipe with one branch closed, pressure waves are formed at the location of the three-way and vortices are formed in the branch pipe. A large velocity gradient will be generated when the fluid flows through the junction area of the main pipe and the branch pipe. The small vortex clusters that continuously fall off are formed at the front edge of branch pipe that; due to the fluid viscosity, the fluid at the front edge of the branch pipe will be driven downstream by the mainstream area, creating a vacuum area at the front edge. At the interface between the main pipe and the branch pipe, the velocity fluctuation of the vortex increases with the increase of the flow velocity., The size of the vortex cluster in the branch pipe increases with the increase of the velocity and the vortex shedding speed at the front edge of the branch pipe increases with the increase of the velocity.

Pump-Valve-Pipeline is an important part of the power plant. It plays a key role in the normal operation of the reactor. The vibration of the system can bring harm to itself and also lead to the safety troubles and noise of other parts. As an important over-flow component, the structure and the adjustment method of check valve is complex, which can lead to pressure fluctuation and result in oscillation problems seriously. The study is to explore the characteristics of the internal flow field and pressure fluctuation of the check valve. Especially, the characteristics of internal flow field and the abnormal fluctuations are concerned during the moving process of the valve core and valve stem. There are many researches focusing on flow vibration under fixed opening of the valve, which can not reflect the real opening process of the valve. In this paper, the abnormal fluctuation of internal flow-field for the check valve is studied. Based on the UDF dynamic grid technology, the transient motion law equation of the moving parts is established as the moving boundary of the fluid. The transient motion analysis model of the check valve is constructed to simulate the dynamic opening process of the valve. The vibration characteristics of the valve with different spring stiffness are studied, which can provide guidance for the regulation of the valve in the system.

The heat transfer tubes of steam generator (SG) are the pressure boundary of primary loop of Pressurized water reactor (PWR), and it is an important barrier to isolate radioactive material. The tubes are prone to fatigue, collision and wear caused by random turbulence excitation of two-phase flow. In the analysis of turbulence excitation, it is necessary to determine the random turbulence excitation based on the dimensionless reference equivalent power spectral density (EPSD), the flow parameters of the secondary side and the correlation length. In single-phase flow, the correlation length can be determined based on the tube gap and tube diameter. Two-phase flow contains two components, the correlation length of random turbulence in two-phase flow is more complicated, and few studies have been done.In this paper, an optimized analysis method on the response ofSG heat transfer tube under random turbulence excitation is proposed by studying the EPSD and the correlation length in two-phase flow. Compared with the traditional spectrum analysis method, this method can consider many nonlinear factors such as clearance, collision and friction. Furtheunore, the characteristics and mechanism of flow induced vibration of heat transfer tubes can be further clarified, and effective measure can be taken at the design stage of SG to effectively reduce the risk of excessive flow induced vibration.

In order to obtain accurate modal parameters of fuel assembly in the seismic test of fuel assembly, the finite element model of fuel assembly is taken as the research object, and the sine sweep signal is used as the excitation to act on the node of the model. On the basis of the transient dynamic analysis results, the transfer function of fuel assembly is obtained by using proper orthogonal decomposition (POD) method, and the modal parameters of the fuel assembly are identified by the least square iteration method, and the frequency, damping ratio and vibration mode of the fuel assembly in each mode are obtained. The transfer function obtained by this method and the transfer function calculated by single node response are used to identify the modal parameters respectively, and the results are compared with those of numerical calculation. The analysis results show that compared with single point response calculation, POD method can extract the key information of multiple nodes in time and space domain, and the calculation results of modal parameter identification are more accurate. This method can be used to identify the modal parameters of the subsequent fuel assembly test, and improve the utilization of the test data and the accuracy of the test results.

In the deep sea, one of the main threats to the structural safety of ships is the impact load caused by reef. This paper established a numerical calculation model which is suitable for simulating the impact load on reef in the deep sea. The model considers the coupling effects of large deformation, fluid-structure interaction, and material plastic deformation. The mesh size, material constitutive model and fluid structure coupling method are studied. The explicit dynamic analysis method is verified by the AISI experiment which there is little difference between the numerical simulation results and the experimental results. Based on the method, the model considering the effect of fluid-structure interaction (FSI) is established and the effectiveness of the FSI is verified by the theoretical results of the national military standard. Then, fluid structure interaction algorithm is studied. Finally, the model which is suitable for simulating the collision between ship and reef in deep sea is established. The effect of reef size and shape on the impact load was studied. It can be seen that the shape and size of the reef mainly affect the contact area and contact stiffness and have a great impact on the impact load. It can provide load input for the structural design of ship and ship equipments. In addition, the model has strong applicability and can be used to calculate the impact load in deep sea. However, the impact load caused by reef also depends on the material property of the ship and reefs condition of the navigation area.

High flux reactor is an important engineering test reactor, which can be used in irradiation research of materials, chemistry, isotopes, medicine and other fields. In the high flux reactor coolant system, there are a large number of nuclear pipes and the layout is complex. The optimization of seismic analysis method for reactor coolant system is an important part in the design process to ensure the nuclear pipes meet the design specifications. The traditional single point response spectrum method needs to envelope the response spectrum of different floors as the analysis input. This method is difficult to give the reasonable seismic load to the numerous nuclear pipes and it will increase the design cost and the difficulty of safety analysis about nuclear pipe. In this paper, an optimized seismic analysis method of reactor coolant system is proposed. By using the multi-point response spectrum method, the optimization of different excitation loading modes for different constrained support points is realized. The analysis results show that the multi-point response spectrum method can solve the problem that different support points are located at different elevation floors in the reactor coolant system, which makes the calculation results more accurate and reasonable. Compared with the traditional method, it can make the design more efficient and practical.

建立了某管道系统的结构振动分析有限元模型,并结合振动试验测试数据,检验了模型的合理性.采用谐响应法,在10～300 Hz频段内开展了管道在泵致激励下的机械振动响应分析,研究了支吊架的刚度、阻尼参数对管道系统泵致振动响应的分析研究,为系统的振动传递优化提出建议.

在桥梁领域,设计桥梁支座主要考虑其隔振效果.据研究表明,锌铝合金具有较低的屈服应力、较高的延展性和不易加工硬化等特性,是一种有潜力的耗能材料.文章针对一种锌铝合金减振支座,考虑支座设计参数影响其减振性能为切入点,分析设计参数下该支座的隔振能力.同时引入桥梁系统进行动力学分析,设计桥梁隔振系统与非隔振系统的地震响应特征进行对比,分析了两种工况下桥梁结构在各个结点的加速度响应变化.结果 显示设计隔振桥梁系统能有效改变结构的自振周期,能主动调控桥梁结构的动力特性,达到良好的隔振效果.

Suitable vibration and noise indices which provide technical direction for vibration and noise reduction, play a very important role in structure analysis and validated test . The contribution of foundation impedance is studied by analyzing the vibration reduction index of a single degree of freedom system. The finite element method (FEM) and boundary element method (BEM) are applied to simulate the vibration and noise indices of a cabin along with internal equipment. The vibration reduction and sound radiation indices of the internal isolator have been calculated to analyze the variation trend with frequency. The results indicate that the difference between vibration level difference and insert loss is very small in most frequency band. Interestingly, the power flow difference and radiated sound power are opposite in phase in middle and high frequency band, which have been proved to be appropriate elements to evaluate the vibration and noise indices of the cabin. The analysis method and procedure can be used to objectively evaluate the vibration reduction property of similar vibration isolators.

Using FEM and BEM, the vibration and noise characteristics of an embedded track was studied when the tram travelling at 60 km/h. The results show that the vibration of the gutter is significant, which can efficiently dissipate vibration energy. The reduction of vibration in the vertical and horizontal directions of the embedded track is significant. The sound radiation level of the embedded track is high at 250 Hz-1 200 Hz frequency range, especially in the frequency ranges of 400 Hz-500 Hz and 800 Hz-1 000 Hz. The biggest noise source contribution comes from the gutter of the embedded track, and the contribution of slab is smaller. By material parameter optimization of the gutter, the optimal Young’s modulus and the damping loss factors of the elastomer, prefabricated blocks and elastic pad were obtained. The sensitive material parameter to the noise of the embedded track was analyzed. Focused on the shape of prefabricated blocks, the better embedded form was acquired by analyzing and comparing. Combination of the optimization results of the material parameters with the optimal shape of the prefabricated blocks can reduce the sound radiation by 1.7 dB(A).