Critical Instability Criterion of Large-Diameter Shafts in Deep Topsoil Based on Ultimate Strain Analysis

Cong, Yu; Liu, Zhulan; Wang, Xiaoshan; Chen, Qiang; Wang, Lei; Kang, Fang; Abi, Erdi

doi:10.3390/su142114552

Cited by 2 publications

(2 citation statements)

References 15 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This can confirm reliability by ensuring that it does not break under extreme conditions that will be used in producing the electric wheelchair drive unit [20,21]. The maximum strain appears at the end of the shaft connected through the pulley and key, with a value of 0.064453 mm, which is very small, allowing cross-verification of safety [22]. Figure 13 is the stress analysis result.…”

Section: Gear Stress Analysismentioning

confidence: 86%

Design of Wheelchair Drive Unit Capable of Driving on Roads and Obstacles with Shape Conversion

Jeong,

Kwon,

Youm

et al. 2024

Applied Sciences

View full text Add to dashboard Cite

Wheelchairs are widely used globally and are essential for providing autonomy and mobility to elderly and disabled people who have movement restrictions. Manual wheelchairs require operation through turning the wheels or pushing the wheelchair directly, thus posing mobility limitations for the user and caregiver. In contrast, electric wheelchairs, when used by the user, allow for improved flexibility by operating the wheelchair through a single control mechanism. However, the use of electric wheelchairs poses challenges in accessing areas with stairs and curbs, limiting the range of activity and thereby diminishing the quality of life for users and those reliant on electric wheelchairs. The electric wheelchair developed in this research incorporates a single motor for lightweight design. It uses a wheel travel variation actuator, eliminating the need for synchronization and allowing for low-power operation. This design reduces power loss from the caterpillar’s idling during wheel movement and includes the implementation of a pulley system. The optimal pulley belt length was calculated, and a deceleration device was installed inside the caterpillar, enabling a design that is compact, lightweight, and capable of high deceleration. On paved roads and flat terrain, the electric wheelchair is designed for high-speed travel using two pairs of front omni wheels and drive wheels. For terrains with stairs, speed bumps, unpaved roads, and unavoidable obstacles, the wheelchair is powered by caterpillars. The electric wheelchair developed through the research presented in this paper has verified the reliability of its transmission system through gear stress and deformation analysis. Additionally, an electric wheelchair based on the proposed concept was constructed to validate the drivability, safety, operability, and convenience of its driving unit. Furthermore, a user rode the constructed electric wheelchair to confirm that there were no issues with its drivability.

show abstract

Section: Gear Stress Analysismentioning

confidence: 86%

Design of Wheelchair Drive Unit Capable of Driving on Roads and Obstacles with Shape Conversion

Jeong,

Kwon,

Youm

et al. 2024

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Several authors have treated the design of circular shafts [8][9][10][11][12][13][14][15][16][17]. However, their implementation in anthropic materials has posed a challenge for this project, given the heterogeneity of the PMWR piles and the difficulty of carrying out mechanical characterizations that accurately reflect the actual behavior of the deposited materials.…”

Section: Introductionmentioning

confidence: 99%

Design and Implementation of Sampling Wells in Phosphate Mine Waste Rock Piles: Towards an Enhanced Composition Understanding and Sustainable Reclamation

El Ghorfi,

Inabi,

Amar

et al. 2024

Minerals

View full text Add to dashboard Cite

Establishing a circular economy in mining begins with a dedicated sampling strategy as its fundamental phase. This specific approach is crucial for enhancing resource retrieval and isolating essential minerals from mining residues. By carefully examining and defining the makeup of waste materials, mining activities can discover overlooked possibilities, promoting sustainability. A thoughtfully planned sampling strategy not only reduces environmental harm but also sets the stage for the effective use of resources. In doing so, the mining industry can shift towards a circular model, adhering to the principles of waste reduction, material reuse, and ultimately promoting a more environmentally conscious and economically viable industry. In the phosphate industry and during the pre-concentration process of phosphate ore through screening, significant amounts of mining waste, consisting of various lithologies including indurated and fine phosphate, coarse-grained silicified phosphate, limestone, and marls, are deposited in waste rock stockpiles. Collecting representative samples from these heterogeneous materials presents challenges in accurately characterizing the entire stockpile. To overcome this issue, circular mining wells were implemented as a novel sampling method in waste rock stockpiles, enabling the collection of intact representative samples. This paper shares a successful experience in constructing three concrete-lined wells within a phosphate mine waste rock stockpile measuring 662 m in length, 240 m in width, and ranging in height from 0 to 65 m. The wells were dug at various depths, ranging from 20 m to 55 m, with a circular section and a diameter of 1.5 m. An integrated method utilizing analytical techniques in conjunction with numerical modeling via Robot Structural Analysis software (version of 2020) was utilized to assess the stress on the well supports and confirm their stability. This methodology serves as a valuable tool for evaluating the stability of similar wells, ensuring the safety of operators. The structural model yielded a stress level of 1 MPa, which aligned with the values obtained from the analytical model. Sensitivity analysis was performed on various parameters (friction angle, Poisson Ratio, and gravity), and the safety factor consistently remained above 1.5 for all scenarios investigated up to a depth of 60 m. Consequently, this study demonstrates that concrete-lined wells can be utilized safely for intact sampling in waste rock stockpiles. This sampling operation will allow the pursuit of optimizing resource utilization and enhancing environmental sustainability, by studying phosphate distribution in the Phosphate Mine Waste Rock (PMWR) for better recovery.

show abstract

Critical Instability Criterion of Large-Diameter Shafts in Deep Topsoil Based on Ultimate Strain Analysis

Cited by 2 publications

References 15 publications

Design of Wheelchair Drive Unit Capable of Driving on Roads and Obstacles with Shape Conversion

Design of Wheelchair Drive Unit Capable of Driving on Roads and Obstacles with Shape Conversion

Design and Implementation of Sampling Wells in Phosphate Mine Waste Rock Piles: Towards an Enhanced Composition Understanding and Sustainable Reclamation

Contact Info

Product

Resources

About