Structural seismic response reconstruction is important to assess the safety of structures. This study presents a novel multidomain feature-guided generative adversarial neural network model (MWGAN-TF) for reconstructing the seismic responses of structures, which takes into account the joint non-stationarity of the seismic response in the time-frequency statistical domain. It innovatively incorporates time, frequency, and statistical-domain feature constraints into the multiscale generative adversarial neural network, which guides the model to learn the multidomain feature information of the seismic response at different time scales. A statistical indicator (CNCSI) was proposed to evaluate the performance of the model in capturing nonstationary characteristics. The effectiveness of the MWGAN-TF was verified using response data from numerical models of a three-story moment-resisting frame and reinforced concrete frame structures, as well as the field measurement data of an actual building. Thereafter, the effects of different domain feature-guided models on the reconstruction response accuracy are discussed. The results show that embedding multidomain feature constraints can provide a more reliable response reconstruction by improving the ability of the model to capture nonstationary characteristics. Thus, the deep learning paradigm based on multidomain feature guidance outperforms the classical neural network guided only by time-domain features.

为分析冻融循环和紫外线对寒区混凝土坝抗震性能的影响,进行了双因素下坝体材料动力性能试验研究和高坝动力特性分析.考虑寒区紫外线辐射量及冻融循环次数,使用紫外线老化箱和冻融循环试验机模拟实际工况,得出紫外线辐照时间及冻融循环次数与寒区混凝土材料动态性能的影响规律;基于试验结果,利用数值方法分析了双因素对大坝动力损伤的影响.结果表明:与理想环境相比,紫外线辐射会降低混凝土的抗压强度和弹性模量;与单一冻融循环因素相比,紫外线与冻融循环双因素加剧了混凝土劣化;强震时,冻融和紫外线对混凝土的劣化影响,增加了大坝的损伤破坏程度.上述试验结果有助于更好地研究多因素对混凝土高坝动态力学性能的影响,可为寒区大坝抗震设计提供参考.

加筋板架广泛应用于船体结构,其优良性能可以为舰船结构的防护及优化设计提供技术支持.本文针对近场水下爆炸冲击荷载作用下加筋结构的动力学响应,基于ALE方法采用LS-DYNA软件对三种加筋形式结构进行了数值模拟,分析了板架的变形响应.结果表明:加强筋的设置方式对板架的变形有一定的影响,当三种类型加筋结构的总质量相同时,井字形加强筋的效果较好;对于矩形截面加强筋,结构动力学性能受高宽比影响较明显,在舰船结构设计中应根据实际情况合理选择.此外,还针对不同爆距作用下加筋板的毁伤特性进行了研究,得到了两种不同的毁伤模式.

This project has dealt with the developing a new technology for a renewable energy source, the wave energy, which is considered as one of the renewable resources with a potential to contribute to a ...

The non-full similarity laws were deduced on the basis of the existing similar theory.The disposal skill was proposed to meet non-full similitude requirements for a descending stage in constitutive relationship of model material.According to the properties of a model material,the numerical reconstruction of dynamic failure model test was conducted to compare the results of prototype,full and non-full similarity models.It was found that the results of the non-full similarity model agree well with those of the prototype for the first four modal shapes and distributions of the maximum tensile stress and damage of a dam body,and the relations between the natural frequencies and the maximum tensile stresses for the prototype and the non-full similarity model meet the non-full similarity requirements; when Poison's ratio of the material model is changed from 0.17 to 0.2 for the non-full similarity model,there are no significant changes of the natural frequencies and modal shapes; the structure's Rayleigh damping is relevant to the natural frequencies and modal damping ratio,so Rayleigh dampings of the prototype and the other models were adopted to solve the problem of damping similarity in the model test.The analysis results for the numerical reconstruction of the dynamic model test of a gravity dam showed that the results of the modal test using numerical reconstruction with a model designed according to non-full similarity laws and certain treatment skills adopted to meet similarity requirements are reliable when the test equipment and conditions,and material don't meet all similitude requirements.

In order to study the dynamic failure mechanism and aseismic measure for high concrete gravity dam under earthquake, the comparative models experiment on the shaking table was conducted to investigate the dynamic damage response of concrete gravity dam with and without the presence of reinforcement and evaluate the effectiveness of the strengthening measure. A new model concrete was proposed and applied for maintaining similitude with the prototype. A kind of extra fine wires as a substitute for rebar was embedded in four-points bending specimens of the model concrete to make of reinforced model concrete. The simulation of reinforcement concrete of the weak zones of high dam by the reinforced model concrete meets the similitude requirements. A tank filled with water is mounted at the upstream of the dam models to simulate the reservoir. The Peak Ground Acceleration (PGA) that induces the first tensile crack at the head of dam is applied as the basic index for estimating the overload capacity of high concrete dams. For the two model dams with and without strengthening tested, vulnerable parts of them are the necks near the crests. The results also indicate that the reinforcement is beneficial for improving the seismic-resistant capacity of the gravity dam.

Earthquake analyses of gravity dams with five different heights in time domains are performed on the fluid-structure coupling model and the added mass model respectively.The hydrodynamic pressures obtained from the two models are compared with Westergaard solutions,and the comparative results show that the accurate results of hydrodynamic pressure can be obtained by Westergaard formula for middle and low dams with the height of about 70m,but reasonable results of the dynamic responses of dam-reservoir system should be obtained by the fluid-structure coupling model for high dams with the height of above 160m.Based on the comparison between the results from fluid-structure coupling model and the added mass model for dynamic responses of dam-reservoir system,it is found that the results of the added mass model are larger than those of fluid-structure coupling model in the views of fundamental frequencies,displacements and peak ground acceleration(PGA)of dams.As for the dams with a height of about 200m,the influence of foundation on damreservoir interaction is significant and must be considered.As for the dams with a height of about 70 m,the influence of foundation can be neglected.

A new multi-scale numerical model is presented using the fractal theory and adopting FEM to simulate the failure of concrete. The relation between the fractal box dimension in large scale and the damage to concrete in small scale is deduced. And the evolutionary process of elastic modulus and strength in small scale is given. Consequently, the multi-scale numerical model is proposed to describe the constitutive relation of concrete between small scale and large scale. A two-dimensional static analysis of a concrete block is performed by using this model and the calculation result is discussed. The propagation of cracks of the concrete block is also studied.

Dynamic model test of dam-water system for Huangdeng gravity dam is carried out on a shaking table.The natural frequency and hydrodynamic pressure on upstream are obtained by the test.The results of fluid-solid coupling finite element model based on Euler formula are well consistent with those of the test while the added mass model amplifies the dynamic response of water on the dam.When the added mass model is applied to engineering,its results should be reduced.Based on the analysis of dam shape,water depth and higher mode,it deduces the dynamic effect distribution factor along the dam height.

On the basis of the similitude law, Emulation Concrete, which meets the similitude requirements, was used for small-scaled dam model test. For the dynamic failure mechanism of concrete gravity dam during earthquake to be studied, the dynamic model test on the shaking table was conducted for a powerhouse dam section. The reservoir and rigid foundation systems were considered in the test. The whole process of concrete gravity dam from elastic deformation, damage, to failure in various levels of Peak Ground Acceleration is studied through the tests. The failure mode of gravity dam is simulated, and the influencing factors are then analyzed by numerical method, which is based on concrete nonlinear elasto-plastic model of damage mechanics. The analytical results are compared with experimental results. The damage patterns obtained from the numerical model are in good agreement with those obtained from shaking table tests including water reservoir effect and rigid foundation. Copyright (c) 2012 John Wiley & Sons, Ltd.

The seismic safety evaluation of dam is always concerned by designers and researchers. Due to the limited field prototype observation data, the dynamic model failure tests become more effective means than numerical analysis to investigate nonlinear dynamic response and failure mechanisms of concrete dam. A large number of the tests had been performed in Dalian university of technology in china. This paper makes a detailed description on the dynamic model test on shaking table. The similitude rules are discussed, the model material is introduced, the procedure is described for the dynamic model test. Based on the PGA(peak ground acceleration) inducing the first tension crack at the model dam body, the response of prototype dam under strong earthquake can be assessed by the test.