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During drilling in coal mines, sticking of drill rod (referred to as SDR in this work) is a potential threat to underground safety. However, no practical measures to deter SDR have been developed yet. The purpose of this study is to develop an anti-SDR strategy using proportional-integral-derivative (PID) and compliance control (PIDC). The proposed strategy is compatible with the drilling process currently used in underground coal mines using drill rigs. Therefore, this study aims to contribute to the PIDC strategy for solving SDR.

A hydraulic circuit to reduce SDR was built based on a load-independent flow distribution system, a PID controller was designed to control the inlet hydraulic pressure of the rotation motor and a typical compliance control approach was adopted to control the feed force and displacement. Moreover, the weight and optimal combination of the alternative admittance control parameters for the feed cylinder were obtained by adopting the orthogonal experiment approach. Furthermore, a fuzzy admittance control approach was proposed to control the feed displacement. Experiments were conducted to test the effectiveness of the proposed method.

The experimental results indicated that the PIDC strategy was appropriate and effective for controlling the rotation motor and feed cylinder; thus, the proposed method significantly reduces the SDR during drilling operations in underground coal mines.

As the PIDC strategy solves the SDR problem in underground coal mines, it greatly improves the safety of coal mine operation and decreases the power cost. Consequently, it brings the considerable benefits of coal mine production and vast application prospects in other corresponding fields. Actual drilling conditions are difficult to accurately simulate in a laboratory; thus, for future work, drilling experiments can be conducted in actual underground coal mines.

The PIDC-based anti-SDR strategy proposed in this study satisfactorily controls the rotation motor and feed cylinder and facilitates the feed and rotation movements. Furthermore, the tangible novelty of this study results is that it improves the frequency response of the entire drilling system. The drilling process with PIDC decreased the occurrence of SDR by 50%; therefore, the anti-SDR strategy can significantly improve the safety and efficiency of underground coal mining.

The typical approach of modeling the aerodynamics of an aircraft is to develop a complete database through testing or computational fluid dynamics (CFD). The database will be huge if it has a reasonable resolution and requires an unacceptable CFD effort during the conceptional design. Therefore, this paper aims to reduce the computing effort required via establishing a general aerodynamic model that needs minor parameters.

The model structure was a preconfigured polynomial model, and the parameters were estimated with a recursive method to further reduce the calculation effort. To uniformly disperse the sample points through each step, a unique recursive sampling method based on a Voronoi diagram was presented. In addition, a multivariate orthogonal function approach was used.

A case study of a flying wing aircraft demonstrated that generating a model with acceptable precision (0.01 absolute error or 5% relative error) costs only 1/54 of the cost of creating a database. A series of six degrees of freedom flight simulations shows that the model’s prediction was accurate.

This method proposed a new way to simplify the model and recursive sampling. It is a low-cost way of obtaining high-fidelity models during primary design, allowing for more precise flight dynamics analysis.

The rock drill’s drill tail experiences high-frequency fretting simultaneously in the rotational and axial directions. Due to the complex working characteristics and the low viscosity of the water medium, the pure water seal is susceptible to damage and failure. The purpose of this paper is to enhance the water seal’s performance.

The Y-shaped seal ring is modeled and simulated using orthogonal testing. Through analysis of the impact of various seal section parameters on sealing performance, the maximum contact stress and maximum Von Mises stress are selected as indicators of sealing effectiveness.

The maximum contact stress is proportional to lip thickness and chamfer length but inversely proportional to lip length. Meanwhile, the maximum Von Mises stress is directly influenced by lip depth and the included angle of the lip and drill tail but is inversely proportional to the lip thickness. The enhanced Y-shaped water seal sees reductions of 15% and 45% in maximum contact stress and maximum Von Mises stress, respectively.

This paper used analytical method and model that is helpful for design of the water seal’s structure in complex working characteristics and the low viscosity of the water medium.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2023-0366/

The evaluation of the conductivity profile of layered metallic structures is performed via the inversion of the impedance of a circular air cored probe coil of rectangular cross section. The inversion approach is based on the implementation of generalised radial basis function neural networks. The choice of the size of the network and the evaluation of its weights are handled by the orthogonal least squares learning algorithm. The merits of the proposed method are illustrated in the light of two examples concerning non‐destructive testing applications.

This paper aims to determine the rational operating regime of a rotary percussive drilling machine under optimal conditions.

An orthogonal array of Taguchi, signal-to-noise (S/N) ratio, ANOVA Pareto analysis and regression analysis are used to investigate the effect of drilling operational factors on the penetration rate. A series of experiments based on orthogonal arrays L₂₇ was carried out, and the results were collected and analyzed using the statistical software Minitab.

The statistical analysis (ANOVA Pareto) of the results showed that among all setting parameters, air pressure is the most essential element that affects the penetration rate. The rational operating regime of the rotary percussive drilling machine was determined with optimum air pressure values of 17 bar (Level 3), rotation speed of 60 rpm (Level 3) and a thrust of 825 kgf (Level 2), which maximize the penetration rate. A quadratic regression model was developed for the penetration rate. The predicted values are compared with the experimental data and are considered to be in good agreement.

The study uses the orthogonal array of Taguchi, S/N ratio, ANOVA Pareto analysis and regression analysis to investigate the effect of drilling operational factors on the penetration rate.

This study aims to examine solid particle erosion behavior of novel hybrid composite materials where borax (B₂O₃) particles (∼150 μm) were added to glass fabric and epoxy resin at an amount of 15 and 30 per cent.

The tests that involved slightly rounded and irregular Al₂O₃ particles having two erodent sizes (200, 400 μm) were conducted at these operational conditions; namely, three impact velocities (23, 34, 53 m/s), two fabric directions (0/90/0, 45/−45/45) and three impingement angles (30°, 60°, 90°). In addition, the design of experiments, which utilizes Taguchi’s robust orthogonal arrays approach, was used and an optimum parameter combination was established, which had a minimum erosion rate. Moreover, scanning electron microscope and X-ray diffraction views show the visual effect of filler material.

All test specimens regardless of their dissimilar characteristics displayed maximum erosion rate at 30° impingement angle. Test specimens with 45/−45/45 fabric direction are more wear-resistant than their counterparts with 0/90/0 fabric direction. The erosion wear of glass fabric reinforced epoxy (GF/EP) composites whose matrix had 15 per cent addition of borax particles was higher than that of neat GF/EP composites. In addition, new composite material formed by including borax particles at a rate of 30 per cent of resin leads to a reduction in erosion rates.

While fabric-reinforced polymers take place in most of the studies conducted on erosive wear of composites, studies involving erosion on composites with filler materials can hardly be encountered.

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

Although the global construction industry has made great contributions to economic development, industry corruption is a challenge for governments all over the world. This paper aims to investigate the causal complexity of organizational corruption by exploring the configuration effect of multiple induced conditions of corruption in the construction sector.

This study is focused on bribery, a specific form of corrupt behavior through a scenario-based survey role-playing game in which participants encounter bribery. A total of 400 Chinese construction sector participants were randomly recruited to complete this survey.

Compared with studies that have identified a number of factors associated with corruption in the construction sector, this study found asymmetry and complexity in the causality of organizational corruption. That is, when a variable causing corruption changes from one condition to its opposite – for example, from fierce to mild competition – the degree of corruption is not necessarily reduced as one may expect.

Anti-corruption measures should not rely solely on the net effects of discrete conditions and the interactions between multiple factors should not be ignored. In other words, anti-corruption strategies should not be implemented in isolation of their context, and pairing control measures with configurations is critical in controlling corruption. Finally, multiple configuration paths should be reconsidered when considering the degree of corruption reduction.

This study proposes a comprehensive analysis framework for addressing organizational corruption in the construction sector by investigating configuration effects of multiple induced conditions and offers a useful method for addressing corruption.

The purpose of this paper is to develop a new formulation using spectral approach, which can predict the wave behavior to uncertain parameters in mid and high frequencies.

The work presented is based on a hybridization of a spectral method called the “wave finite element (WFE)” method and a non-intrusive probabilistic approach called the “polynomial chaos expansion (PCE).” The WFE formulation for coupled structures is detailed in this paper. The direct connection with the conventional finite element method allows to identify the diffusion relation for a straight waveguide containing a mechanical or geometric discontinuity. Knowing that the uncertainties play a fundamental role in mid and high frequencies, the PCE is applied to identify uncertainty propagation in periodic structures with periodic uncertain parameters. The approach proposed allows the evaluation of the dispersion of kinematic and energetic parameters.

The authors have found that even though this approach was originally designed to deal with uncertainty propagation in structures it can be competitive with its low time consumption. The Latin Hypercube Sampling (LHS) is also employed to minimize CPU time.

The approach proposed is quite new and very simple to apply to any periodic structures containing variabilities in its mechanical parameters. The Stochastic Wave Finite Element can predict the dynamic behavior from wave sensitivity of any uncertain media. The approach presented is validated for two different cases: coupled waveguides with and without section modes. The presented results are verified vs Monte Carlo simulations.