The crack tip stress field of rock is analyzed under blast loading, and the crack arrest criterion, the conditions of rock crack initiation and crack extension are presented in this paper. The study will help the design of maintaining the stability of stope drift active workings.
This paper presents a three-dimensional viscoelastic model to study the interactions of a penny-shaped interfacial crack and a center of dilatation in the infinite viscoelastic bimaterial, which can model the rock fracture subjected to stress and thermal dilatation during some engineering process. A distinct issue associated with the present work is the incorporation of viscoelastic behavior of bimaterial. The proposed problem is first transformed into the Laplace space, and the solution in the transform space is obtained by decomposing the original problem into two auxiliary problems: (I) a center of dilatation near a bimaterial interface (no crack); and (II) a penny-shaped interfacial crack subject to internal tractions that cancel out those induced in auxiliary problem (I). The mode I, II and III stress intensity factors (SIFs) in the time domain are obtained with the inverse Laplace transform.
Tunnel and underground engineering projects have certain failure risks during construction and operation, including the risk of durability failure to which the study is not enough. In this paper, a whole set of research method for analysis, assessment and calculation on durability risk was proposed on the basis of identification to durability risk factors of large underground concrete structures. That is: this paper provided a method of reliability calculation by establishing failure mode and limit-state-equations according to reliability theory; then, classified and collated various risk factors by taking methods of analytic hierarchy process (AHP) and fault tree analysis (FTA); after that, the quantitative analysis of structural durability was done in accordance with Monte - Carlo (M-C) method. Finally, as an example, for the project of passage across the Yangtze River in Chongming, Shanghai, the above methods were applied to estimate the risk of durability failure of segment component. Effective measures and methods were presented and adopted to enhance the durability capacity of structure according to the results of analysis and assessment.
The carrying capacity and energy absorption characteristic of foamed aluminum (or aluminum foam), fabricated by melt foaming technique, are limited due to the lower strength of aluminum. The typical anti-vibration energy absorbing structures are designed as foamed aluminum-filled or sandwich structures. The deformation and absorption characteristics of foamed aluminum-filled structures subjected to impact loadings are analyzed using experimental and numerical methods in this work. The analysis shows that the steel shell of the combinative structure subjected to dynamic loadings dominates during energy absorption. The energy absorption capacity and initial instability loading increase as impact velocity increase and as increasing shell thickness duo to the interaction between steel shell and aluminum foam. The impact mass within the range of 100kg influences weakly on peak instability loading. Since the steel shell is the dominating part of load capacity and energy absorption, the reasonable design, taking into account of foam density and shell thickness and taking full advantage of interaction between steel shell and aluminum foam, should be adopted to increase the energy absorption characteristic of foam-filled structures.
The experimental study method of the multi-layered spaced protective structure with stiffeners, which is called structural target, is presented penetrated by projectiles in this paper. Many parameters of the terminal ballistics effects and damage model of structural target are obtained after the experiment in which experimental projectiles are used to penetrate the target with stiffeners and steel plate target vertically, offering the basic experimental phenomenon and data for the mechanism research of projectile penetrating structural target (protective structure with stiffeners). In the meantime, the effect of the stiffeners on the failure mode of the structural target and the effect of the thickness and stiffness of stiffeners in the structural target are analyzed preliminarily. This paper could be helpful in the design of the protecting structures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.