Engineering Computations最新文献

Purpose

The purpose of this paper is to develop an appropriate machine learning model for predicting soil compaction degree while also examining the contribution rates of three influential factors: moisture content, electrical conductivity and temperature, towards the prediction of soil compaction degree.

Design/methodology/approach

Taking fine-grained soil A and B as the research object, this paper utilized the laboratory test data, including compaction parameter (moisture content), electrical parameter (electrical conductivity) and temperature, to predict soil degree of compaction based on five types of commonly used machine learning models (19 models in total). According to the prediction results, these models were preliminarily compared and further evaluated.

Findings

The Gaussian process regression model has a good effect on the prediction of degree of compaction of the two kinds of soils: the error rates of the prediction of degree of compaction for fine-grained soil A and B are within 6 and 8%, respectively. As per the order, the contribution rates manifest as: moisture content > electrical conductivity >> temperature.

Originality/value

By using moisture content, electrical conductivity, temperature to predict the compaction degree directly, the predicted value of the compaction degree can be obtained with higher accuracy and the detection efficiency of the compaction degree can be improved.

Purpose

Realistic composite vehicles with 2, 3, 5 and 9 axles, consisting of a truck with one or two trailers, are addressed in this paper by computational models for vehicle–bridge interaction analysis.

Design/methodology/approach

The vehicle–bridge interaction (VBI) models are formed by sets of 2-D rigid blocks interconnected by mass, damping and stiffness elements to simulate their suspension system. The passage of the vehicles is performed at different speeds. Several rolling surface profiles are admitted, considering the maintenance grade of the pavement. The spectral density functions are generated from an experimental database to form the longitudinal surface irregularity profiles. A computational code written in Phyton based on the finite element method was developed considering the Euler–Bernoulli beam model.

Findings

Several models of composite heavy vehicles are presented as manufactured and currently travel on major roads. Dynamic amplification factors are presented for each type of composite vehicle.

Research limitations/implications

The VBI models for compound heavy vehicles are 2-D.

Social implications

This work contributes to improving the safety and lifetime of the bridges, as well as the stability and comfort of the vehicles when passing over a bridge.

Originality/value

The structural response of the bridge is affected by the type and size of the compound vehicles, their speed and the conservative grade of the pavement. Moreover, one axle produces vibrations that can be superposed by the vibrations of the other axles. This effect can generate not usual dynamic responses.

Purpose

The aim of this article is to obtain a stable tensegrity structure by using the minimum knowledge of the structure.

Design/methodology/approach

Three methods have been formulated based on the eigen value decomposition (EVD) and singular value decomposition theorems. These two theorems are being implemented on the matrices, which are computed from the minimal data of the structure. The required minimum data for the structure is the dimension of the structure, the connectivity matrix of the structure and the initial force density matrix computed from the type of elements. The stability of the structure is analyzed based on the rank deficiency of the force density matrix and equilibrium matrix.

Findings

The main purpose of this article is to use the defined methods to find (1) the nodal coordinates of the structure, (2) the final force density values of the structure, (3) single self-stress from multiple self-stresses and (4) the stable structure.

Originality/value

By using the defined approaches, one can understand the difference of each method, which includes, (1) the selection of eigenvalues, (2) the selection of nodal coordinates from the first decomposition theorem, (3) the selection of mechanism mode and force density values further and (4) the solution of single feasible self-stress from multiple self-stresses.

Purpose

In this paper, based on the density functional theory (DFT) and finite element method (FEM), the elastic, buckling and vibrational behaviors of the monolayer bismuthene are studied.

Design/methodology/approach

The computed elastic properties based on DFT are used to develop a finite element (FE) model for the monolayer bismuthene in which the Bi-Bi bonds are simulated by beam elements. Furthermore, mass elements are used to model the Bi atoms. The developed FE model is used to compute Young's modulus of monolayer bismuthene. The model is then used to evaluate the buckling force and fundamental natural frequency of the monolayer bismuthene with different geometrical parameters.

Findings

Comparing the results of the FEM and DFT, it is shown that the proposed model can predict Young's modulus of the monolayer bismuthene with an acceptable accuracy. It is also shown that the influence of the vertical side length on the fundamental natural frequency of the monolayer bismuthene is not significant. However, vibrational characteristics of the bismuthene are significantly affected by the horizontal side length.

Originality/value

DFT and FEM are used to study the elastic, vibrational and buckling properties of the monolayer bismuthene. The developed model can be used to predict Young's modulus of the monolayer bismuthene accurately. Effect of the vertical side length on the fundamental natural frequency is negligible. However, vibrational characteristics are significantly affected by the horizontal side length.

Purpose

There have been limited investigations on the mechanical characteristics of tunnels supported by corrugated plate structures during fault dislocation. The authors obtained circumferential and axial deformations of the spiral corrugated pipe at various fault displacements. Lastly, the authors examined the impact of reinforced spiral stiffness and soil constraints on the support performance of corrugated plate tunnels under fault displacement.

Design/methodology/approach

By employing the theory of similarity ratios, the authors conducted model tests on spiral corrugated plate support using loose sand and PVC (polyvinyl chloride) spiral corrugated PE pipes for cross-fault tunnels. Subsequently, the soil spring coefficient for tunnel–soil interaction was determined in accordance with ASCE (American Society of Civil Engineers) specifications. Numerical simulations were performed on spiral corrugated pipes with fault dislocation, and the results were compared with the experimental data, enabling the determination of the variation pattern of the soil spring coefficient.

Findings

The findings indicate that the maximum axial tensile and compressive strains occur on both sides of the fault. As the reinforced spiral stiffness reaches a certain threshold, the deformation of the corrugated plate tunnel and the maximum fault displacement stabilize. Furthermore, a stronger soil constraint leads to a lower maximum fault displacement that the tunnel can withstand.

Research limitations/implications

In this study, the calculation formula for density similarity ratio cannot be taken into account due to the limitations of the helical corrugated tube process and the focus on the deformation pattern of helical corrugated tubes under fault action.

Originality/value

This study provides a basis for the mechanical properties of helical corrugated tube tunnels under fault misalignment and offers optimization solutions.