Heng Zhang

Dr. Heng Zhang

Hohai university
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
8 July 2021 in Symmetry
Verified
Journal Article
Open access
PDF file
HZHeng Zhang
Heng Zhang
CSChao Su
Chao Su
JBJiawei Bai
Jiawei Bai
RYRongyao Yuan
Rongyao Yuan
YMYujun Ma
Yujun Ma
WWWenjun Wang
Wenjun Wang
In soft soil engineering projects, the building loads are always required to be symmetrically distributed on the surface of the foundation to prevent uneven settlement. Even if the buildings and soft clay are controlled by engineers, it can still lead to the rheology of the foundation. The analytical solution based on the Laplace integral transformation method has positive significance for providing a simple and highly efficient way to solve engineering problems, especially in the long-term uneven settlement deformation prediction of buildings on soft soil foundations. This paper proposes an analytical solution to analyze the deformation of soft soil foundations. The methodology is based on calculus theory, Laplace integral transformation, and viscoelastic theory. It combines an analytical solution with finite theory to solve the construction sequences and loading processes. In addition, an improved quantum genetic algorithm is put forward to inverse the parameters of soft soil foundations. The analytical solution based on Laplace integral transformation is validated through an engineering case. The results clearly illustrate the accuracy of the method.

1 January 2021 in Advances in Civil Engineering
Verified
Journal Article
Open access
PDF file
RYRongyao Yuan
Rongyao Yuan
YYYang Yang
Yang Yang
SCSu Chao
Su Chao
SHShaopei Hu
Shaopei Hu
HZHeng Zhang
Heng Zhang
ECEnhua Cao
Enhua Cao
Magnetorheological (MR) dampers, as an intelligent vibration damping device, can quickly change the damping size of the material in milliseconds. The traditional semiactive control strategy cannot give full play to the ability of the MR dampers to consume energy and reduce vibration under different currents, and it is difficult to control the MR dampers accurately. In this paper, a semiactive control strategy based on reinforcement learning (RL) is proposed, which is based on “exploring” to learn the optimal value of the MR dampers at each step of the operation, the applied current value. During damping control, the learned optimal action value for each step is input into the MR dampers so that they provide the optimal damping force to the structure. Applying this strategy to a two‐layer frame structure was found to provide more accurate control of the MR dampers, significantly improving the damping effect of the MR dampers.

9 August 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
RYRongyao Yuan
Rongyao Yuan
SCSu Chao
Su Chao
ECEnhua Cao
Enhua Cao
SHShaopei Hu
Shaopei Hu
HZHeng Zhang
Heng Zhang
Affected by various complex factors, dam deformation monitoring data usually reflect volatility and non-linear characteristics, and traditional prediction models are difficult to accurately capture the complex laws of dam deformation. A multi-scale deformation prediction model based on Variational Modal Decomposition (VMD) signal decomposition technology is proposed in this study. The method first decomposes the original deformation sequence into a series of sub-sequences with different frequencies, then the decomposed sub-sequences are modeled and predicted by Long Short-Term Memory neural network (LSTM) and Random Forest (RF) according to different frequencies. Finally, the prediction results of all sub-sequences are reconstructed to obtain the final deformation prediction results. In this process, it is proposed to use the instantaneous frequency mean method to determine the decomposition modulus of VMD. The innovation of this paper is to decompose the monitoring data with high volatility, and use LSTM and RF prediction, respectively, according to the frequency of the monitoring data, so as to realize the more accurate capture of volatility data during the prediction process. The case analysis results show that the proposed model can effectively solve the negative impact of the original data volatility on the prediction results, and is superior to the traditional prediction models in terms of stability and generalization ability, which has an important reference value for accurately predicting dam deformation and has far-reaching engineering significance.

18 July 2021
Verified
Conference Paper
Closed access
LGLikun Gao
Likun Gao
HZHeng Zhang
Heng Zhang
CLCheng-Lin Liu
Cheng-Lin Liu
Connectionist Temporal Classification (CTC) is an objective function for sequence learning and has shown promising results in speech and text recognition tasks. However, its inherent mechanism has not been investigated thoroughly. In this paper, we propose a theoretical explanation of CTC from the perspective of the Expectation-Maximization (EM) algorithm. Based on the EM analysis, we propose a pseudo-label-based L1 regularization and voting decoding algorithm to improve the performance of text recognition. The L1 regularization can reduce the pseudo-label estimation error, while the voting decoding algorithm modifies the built-in decoding logic of CTC and introduces a voting mechanism to the inference process. Experiments of handwritten text recognition show that the proposed method consistently improves over the CTC baseline and yields state-of-the-art results on three benchmark datasets.

1 January 2022 in Advances in Civil Engineering
Verified
Journal Article
Open access
PDF file
SHShaopei Hu
Shaopei Hu
SCSu Chao
Su Chao
HZHeng Zhang
Heng Zhang
ECEnhua Cao
Enhua Cao
RYRongyao Yuan
Rongyao Yuan
YXYunquan Xu
Yunquan Xu
The traditional Three‐dimensional (3D) model for stability analysis of a large underground cavern group only includes the main powerhouse, the main transformer chamber, the tailrace surge tank, the main electrical wire hall, and part of the diversion tunnel and tailwater tunnel. Other caverns excavation are not taken into consideration, which is inconsistent with the actual project. In this study, a 3D Finite Element Method (FEM) model, including all the cavities, and a 3D simplified model containing only part of the cavities were established based on the actual underground cavern group project. We study the structural characteristics of the cavern group during excavation via 3D nonlinear FEM. At the same time, three numerical calculation schemes are designed for comparison. The results show that the simulated distributions of the stress field, deformation field, and plastic zone of the two numerical models are similar, but the magnitudes of the 3D FEM model, which considers all caverns are generally higher than the simplified model. The difference between the two simulated horizontal displacements of the main powerhouse reaches 53.72%. Therefore, from the perspective of engineering safety and actual construction, it is advisable to adopt the 3D FEM model, including all the cavities, when conducting a simulation analysis of the underground cavern group.

30 October 2020 in Mathematical Problems in Engineering
Verified
Journal Article
Open access
PDF file
CSChao Su
Chao Su
HZHeng Zhang
Heng Zhang
SHShaopei Hu
Shaopei Hu
JBJiawei Bai
Jiawei Bai
JDJianjian Dai
Jianjian Dai
The computational efficiency and nonconvergence of the iteration are two main difficulties in contact problems, especially in the creep of the foundation. This paper proposes a method to analyze the structural soft foundation system affected by time. The methodology is an explicit method, combining the finite element method with the analytical method. The creep deformation of soft foundation is obtained based on Laplace transforms. The structural deformation contains the statically determinate structural deformation and rigid body displacement, solved by the finite method. The contact forces are calculated by the deformation coordination equations and equilibrium equations. The methodology is validated through augmented Lagrangian (AL) method. The results can clearly illustrate the local disengagement phenome, greatly overcome the nonconvergence of the iteration, and significantly improve computing efficiency.