Research on the Shock Response Characteristics of a Threaded Connection Using the Thin-Layer Element Method

Nonlinear factors such as the contact stiffness and friction damping at the threaded interface of a projectile–fuse system significantly affect the dynamic response characteristics. To obtain the dynamic response of the fuse body accurately during penetration, it is necessary to characterize these nonlinear factors reasonably. Because the existing structural dynamics software cannot effectively deal with nonlinear factors, the thin-layer element method was used to represent the nonlinear factors in this study. By combining the thread elastic model with thin-layer element principles, an effective method for determining the material parameters of the thin-layer element was established theoretically, which provided a different method of determining material parameters, not just relying on experiments. The accuracy of the material parameters was verified based on modal experiments with threaded tubes having different specifications. The errors were within 5%, indicating the reliability of the theoretical determination method for the material parameters. In addition, projectile penetration into a semi-infinite concrete target was tested to verify the accuracy of the thin-layer element modeling. Compared with the ‘TIED’ constraint method, the resonant frequency obtained with the thin-layer element method was in better agreement with that of the experimental data. The maximum error decreased from 15.7 to 7.8%, indicating that the thin-layer element method could accurately represent the nonlinear factors. Thus, this study serves as a reference for accurately evaluating the dynamic response of the fuse body of a penetrator.

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Numerical Investigation on Dynamic Response and Failure Modes of Rock Slopes with Weak Interlayers Using Continuum-Discontinuum Element Method

Frontiers in Earth Science ◽

10.3389/feart.2021.791458 ◽

2021 ◽

Vol 9 ◽

Author(s):

Chengwen Wang ◽

Xiaoli Liu ◽

Danqing Song ◽

Enzhi Wang ◽

Jianmin Zhang

Keyword(s):

Dynamic Response ◽

Failure Modes ◽

Failure Process ◽

Amplification Coefficient ◽

Rock Slopes ◽

Earthquake Excitation ◽

Good Correspondence ◽

Response Characteristics ◽

Damage Degree ◽

Element Method

In order to better understand the dynamic response and failure modes of rock slopes containing weak interlayers subjected to earthquake excitation, a series of numerical simulations were carried out using the continuum-discontinuum element method (CDEM), considering the influence of seismic amplitude and weak interlayers inclination. The seismic response characteristics of slopes were systematically analyzed according to the waveform characteristics, amplification effect, equivalent crack ratio, etc. The numerical results show that the acceleration waveform characteristics and peak ground displacement (PGD) amplification coefficient have good correspondence with the dynamic failure process of landslides. Comprehensive analysis of waveform characteristics and PGD amplification coefficient can determine the damage time, damage location, and damage degree of landslides. The landslide process can be divided into three stages according to the equivalent crack ratio: rapid generation of a large number of microcracks, expansion and aggregation of microcracks, and penetration of micro-cracks and the formation of slip surfaces. The equivalent crack ratio provides a new idea for evaluating slope stability. In addition, under the combination of different amplitudes and weak interlayers, these earthquake-induced landslides exhibit different failure modes: the failure of the gentle-dip slope is mainly local rockfall; The mid-dip and steep-dip slopes with small amplitudes experience “tensile cracking-slip-collapsing” failure; The steep-dip slopes under strong earthquake failed in the form of “tensile cracking-slip-slope extrusion-collapsing”. The research results are of great significance for a deeper understanding of the formation mechanism of rock landslides with weak interlayers and the prevention of such landslide disasters.

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Research and application of improved thin-layer element method of aero-engine bolted joints

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016643978 ◽

2016 ◽

Vol 231 (5) ◽

pp. 823-839 ◽

Cited By ~ 1

Author(s):

Xingyu Yao ◽

Jianjun Wang ◽

Xue Zhai

Keyword(s):

Stress Distribution ◽

Thin Layer ◽

Contact Stress ◽

Experimental Results ◽

Bolted Joints ◽

Material Parameters ◽

Aero Engine ◽

Interface Contact ◽

Contact Stress Distribution ◽

Element Method

A new dynamic modeling method called the improved thin-layer element method is proposed to apply to the aero-engine bolted joints. The thin-layer elements are partitioned based on the interface contact stress distribution. In addition, the material parameters of the partitioned thin-layer elements are determined by the bolted joints stiffness technique and the fractal contact theory without the experimental results, which allows the engineer to estimate the dynamic characteristics of whole structure before the physical prototype is available. First, the modeling principles of the improved thin-layer element method are studied and the bolted joints stiffness is analyzed. Next, the material parameters of the partitioned thin-layer elements are determined on the basis of the interface contact stress distribution characteristics of the bolted joints. Finally, this method is applied to the simulative casing bolted joints structure and the results are compared with the experimental results in order to verify the proposed method. The results indicate that the improved thin-layer element method is more accurate than the thin-layer elements method, and the material parameters of the partitioned thin-layer elements can be expressed by the structural parameters of the aero-engine bolted joints without updating based on the experiment.

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Dynamic response analysis of submerged soil by thin layer element method

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(92)91790-c ◽

1992 ◽

Vol 29 (6) ◽

pp. 361

Keyword(s):

Dynamic Response ◽

Thin Layer ◽

Response Analysis ◽

Dynamic Response Analysis ◽

Submerged Soil ◽

Element Method

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Dynamic response analysis of submerged soil by thin layer element method

Soil Dynamics and Earthquake Engineering ◽

10.1016/0267-7261(92)90023-7 ◽

1992 ◽

Vol 11 (1) ◽

pp. 17-26 ◽

Cited By ~ 10

Author(s):

T. Nogami ◽

M. Kazama

Keyword(s):

Dynamic Response ◽

Thin Layer ◽

Response Analysis ◽

Dynamic Response Analysis ◽

Submerged Soil ◽

Element Method

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Application of the Finite Element Method in Screening of Body Turn up Heights for Radial Truck Tires

Tire Science and Technology ◽

10.2346/1.2135238 ◽

2001 ◽

Vol 29 (3) ◽

pp. 186-196 ◽

Cited By ~ 5

Author(s):

X. Yan

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Material Model ◽

The Finite Element Method ◽

Truck Tires ◽

Contact Constraint ◽

Nonlinear Mechanical ◽

Critical Regions ◽

Constraint Method ◽

Element Method

Abstract A method is described to predict relative body turn up endurance of radial truck tires using the finite element method. The elastomers in the tire were simulated by incompressible elements for which the nonlinear mechanical properties were described by the Mooney-Rivlin model. The belt, carcass, and bead were modeled by an equivalent orthotropic material model. The contact constraint of a radial tire structure with a flat foundation and rigid rim was treated using the variable constraint method. Three groups of tires with different body turn up heights under inflation and static footprint loading were analyzed by using the finite element method. Based on the detail analysis for stress analysis parameters in the critical regions in the tires, the relative body turn up edge endurance was predicted.

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