Consideration of dilation in studying the dynamics of crushing zone development in an elastoplastic material with camouflet explosion of a concentrated charge

Abstract Vehicles, such as an agricultural tractor, construction vehicle, mobile machinery, and 4-wheel drive vehicle, are often operated on unpaved ground. In many cases, the ground is deformable; therefore, the deformation should be taken into consideration in order to assess the off-the-road performance of a tire. Recent progress in computational mechanics enabled us to simulate the large scale coupling problem, in which the deformation of tire structure and of surrounding medium can be interactively considered. Using this technology, hydroplaning phenomena and tire traction on snow have been predicted. In this paper, the simulation methodology of tire/soil coupling problems is developed for pneumatic tires of arbitrary tread patterns. The Finite Element Method (FEM) and the Finite Volume Method (FVM) are used for structural and for soil-flow analysis, respectively. The soil is modeled as an elastoplastic material with a specified yield criterion and a nonlinear elasticity. The material constants are referred to measurement data, so that the cone penetration resistance and the shear resistance are represented. Finally, the traction force of the tire in a cultivated field is predicted, and a good correlation with experiments is obtained.

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Tourism as a Key for Regional Revitalization?: A Quantitative Evaluation of Tourism Zone Development in Japan

Sustainability ◽

10.3390/su13137478 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7478

Author(s):

Hyunjung Kim ◽

Eun Jung Kim

Keyword(s):

Positive Impact ◽

Control Group ◽

Control Group Design ◽

Group Design ◽

Narrow Region ◽

Quasi Experimental ◽

Zone Development ◽

The Government ◽

Urban And Regional Development ◽

National Industry

Since the dawn of the 21st century, Japan has switched its national industry strategy from traditional industries—manufacturing and trading—toward tourism. Regional revitalization is a particularly important issue in Japan, and by uniting regions as an integrated tourism zone, the government expects an increase in visits to tourism zones. This study quantitatively evaluates whether the regions that contain a tourism zone experience a significant increase in visitors by using a quasi-experimental pretest–posttest control group design. Additionally, it examines the effects of subsidies through regression modeling. The results indicated that the tourism zones that were comprised of a narrow region in the same prefectures experienced a significant increase in visitors. The subsidy on information transmission, measures for the secondary traffic, and space formation had a significant positive impact on the increase in visitors to these tourism zones. Implications on tourism policies, urban and regional development, and community development can be obtained through this study.

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A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽

10.3390/ma14112784 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2784

Author(s):

Georgios Maliaris ◽

Christos Gakias ◽

Michail Malikoutsakis ◽

Georgios Savaidis

Keyword(s):

Process Parameters ◽

Material Properties ◽

Shot Peening ◽

Qualitative Assessment ◽

Experimental Investigations ◽

Elastoplastic Material ◽

Size Distributions ◽

User Friendly ◽

The Impact ◽

2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

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