scholarly journals Numerical Investigation of the Dynamic Responses and Damage of Linings Subjected to Violent Gas Explosions inside Highway Tunnels

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Zhipeng Li ◽  
Shunchuan Wu ◽  
Ziqiao Cheng ◽  
Yibo Jiang
Keyword(s):  
Numerical Simulation ◽  
Blast Loading ◽  
Damage Mechanism ◽  
Relevant Information ◽  
Dynamic Responses ◽  
Economic Losses ◽  
Future Research ◽  
Gas Explosion ◽  
Empirical Formulas ◽  
Fully Coupled

The linings of structures suffer severe damage when subjected to internal explosions, which cause numerous casualties and incalculable economic losses. In this paper, a violent gas explosion that occurred inside a highway tunnel in the city of Chengdu, China, is studied through numerical simulations. The evaluated energy of the gas explosion was equivalent to 2428.9 kg of TNT. A fully coupled numerical model consisting of five parts is established with dimensions consistent with the real prototype dimensions and by considering fluid-structure interaction (FSI) effects. Then, a detailed modelling process is presented and validated through a comparison with empirical formulas. This paper investigates the strength and propagation characteristics of a blast shock wave inside the tunnel, and both the effective stresses and dynamic responses of the lining are analysed under the blast impact loading. The damage mechanism is studied, and the evolution of the lining damage is reproduced, the results of which show good agreement with the actual conditions. Moreover, in terms of the responses and damage of the lining, the fully coupled blast loading model has obvious advantages in comparison with the simplified blast loading model. Furthermore, the damage assessment of the lining conducted using the single degree of freedom (SDOF) method agrees well with the results of the numerical simulation and site investigations. The comprehensive numerical simulation technique used in the present paper and its results could represent valuable references for future research on violent explosions within tunnels or very large underground structures and provide relevant information for the blast-resistant design of such structures.

Research on Damage Mechanism of Aluminum Foam Sandwich Plate Subjected to Blast Loading

2015 ◽  
Vol 1119 ◽  
pp. 794-798
Author(s):  
Zheng Wang ◽  
Wen Li Yu ◽  
Tao Wang ◽  
Jin Tao Wang
Keyword(s):  
Numerical Simulation ◽  
Aluminum Foam ◽  
Sandwich Plate ◽  
Blast Loading ◽  
Simulation Method ◽  
Damage Mechanism ◽  
Sandwich Plates ◽  
Destructive Effect ◽  
Damage Pattern ◽  
Damage Degree

This paper investigated the damage degree and damage mechanism of aluminum sandwich plate subjected to blast loading by using numerical simulation method. Finite elements models of aluminum foam sandwich plates were established. The distortion and damage pattern of the sandwich plate under different masses of detonator were got by using LS-DYNA to simulate the destructive effect of shock wave and detonation product against sandwich plate. The results showed that the maximal deflection and overloading of the sandwich plates were different because of the changing of mass of detonator. This paper could provide some reference for the designing of sandwich structures.

scholarly journals Modelling and Dynamic Response of Steel Reticulated Shell under Blast Loading

2013 ◽  
Vol 20 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Ximei Zhai ◽  
Yonghui Wang
Keyword(s):  
Finite Element ◽  
Single Layer ◽  
Blast Loading ◽  
Element Model ◽  
Dynamic Responses ◽  
Empirical Formulas ◽  
Structural Dynamic ◽  
Explicit Finite Element ◽  
Long Span ◽  
Tnt Equivalent

Explicit finite element programme LS-DYNA was used to simulate a long-span steel reticulated shell under blast loading to investigate the structural dynamic responses in this paper. The elaborate finite element model of the Kiewitt-8 single-layer reticulated shell with span of 40 m subjected to central blast loading was established and all the process from the detonation of the explosive charge to the demolition, including the propagation of the blast wave and its interaction with structure was reproduced. The peak overpressure from the numerical analysis was compared with empirical formulas to verify the credibility and applicability of numerical simulation for blast loading. The dynamic responses of the structure under blast loading with different TNT equivalent weights of explosive and rise-span ratios were obtained. In addition, the response types of Kiewitt-8 single-layer reticulated shell subjected to central explosive blast loading were defined.

Numerical Simulation for Failure Modes of Reinforced Concrete Beams under Blast Loading

2010 ◽  
Vol 163-167 ◽  
pp. 1359-1363
Author(s):  
Xiu Hua Zhang ◽  
Yan Yan Wu ◽  
Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Failure Modes ◽  
Kinematic Hardening ◽  
Blast Loading ◽  
Material Model ◽  
Reinforced Concrete Beams ◽  
Dynamic Responses ◽  
Rc Beams ◽  
Tnt Equivalent

The reinforced concrete (RC) beams have three failure modes using large-scale finite element procedure LS-DYNA to simulate dynamic responses and failure modes of RC beams under blast loading. Holmquist-Johnson-Cook material model was used in concrete, the damage and strain rate effects were considered the kinematic hardening plasticity material model was used in reinforcing bars. With different rebar ratios and charges of weight TNT equivalent and stand-off distance were investigated and discussed. The numerical simulation can predict responses and flexure, flexure-shear and direct shear of the RC beams under different blast loading. The influence of the several factors have been identified and provided a theoretical basis for blast resistant design and retrofitting of the RC beam.

scholarly journals Biomedical Properties of Propolis on Diverse Chronic Diseases and Its Potential Applications and Health Benefits

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 78
Author(s):  
Nelly Rivera-Yañez ◽  
C. Rebeca Rivera-Yañez ◽  
Glustein Pozo-Molina ◽  
Claudia F. Méndez-Catalá ◽  
Adolfo R. Méndez-Cruz ◽  
...  
Keyword(s):  
Alternative Medicine ◽  
Chronic Diseases ◽  
Geographical Origin ◽  
Complex Mixture ◽  
Relevant Information ◽  
Economic Losses ◽  
Primary Health ◽  
Potential Applications ◽  
Obesity And Cancer ◽  
Resinous Product

The use of alternative medicine products has increased tremendously in recent decades and it is estimated that approximately 80% of patients globally depend on them for some part of their primary health care. Propolis is a beekeeping product widely used in alternative medicine. It is a natural resinous product that bees collect from various plants and mix with beeswax and salivary enzymes and comprises a complex mixture of compounds. Various biomedical properties of propolis have been studied and reported in infectious and non-infectious diseases. However, the pharmacological activity and chemical composition of propolis is highly variable depending on its geographical origin, so it is important to describe and study the biomedical properties of propolis from different geographic regions. A number of chronic diseases, such as diabetes, obesity, and cancer, are the leading causes of global mortality, generating significant economic losses in many countries. In this review, we focus on compiling relevant information about propolis research related to diabetes, obesity, and cancer. The study of propolis could generate both new and accessible alternatives for the treatment of various diseases and will help to effectively evaluate the safety of its use.

Modelling and numerical simulation of thick sheet double slitting process using continuum damage mechanics

2014 ◽  
Vol 23 (8) ◽  
pp. 1150-1167 ◽  
Author(s):  
Yosr Ghozzi ◽  
Carl Labergere ◽  
Khemais Saanouni ◽  
Anthony Parrico
Keyword(s):  
Numerical Simulation ◽  
Constitutive Equations ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Thick Sheet ◽  
Technological Parameters ◽  
Strongly Coupled ◽  
Mixed Hardening ◽  
Elasto Plasticity ◽  
Fully Coupled

This work concerns the modelling and numerical simulation of specific thick sheet cutting process using advanced constitutive equations accounting for elasto-plasticity with mixed hardening fully coupled with isotropic ductile damage. First, the complex kinematics of the different tools is modelled with specific boundary conditions. Second, the fully and strongly coupled constitutive equations are summarized and the associated numerical aspects are shortly presented. An inverse material identification procedure is used to determine the convenient values of the material parameters. Finally, the double slitting process is numerically simulated and the influence of the main technological parameters studied focusing on the cutting forces.

scholarly journals Comparative Transcriptomic Analysis of Riptortus pedestris (Hemiptera: Alydidae) to Characterize Wing Formation across All Developmental Stages

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 226
Author(s):  
Siying Fu ◽  
Yujie Duan ◽  
Siqi Wang ◽  
Yipeng Ren ◽  
Wenjun Bu
Keyword(s):  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Average Length ◽  
Transcriptome Assembly ◽  
Expression Profiles ◽  
Economic Losses ◽  
Future Research ◽  
Economic Damage ◽  
Wing Formation ◽  
Riptortus Pedestris

Riptortus pedestris (Hemiptera: Alydidae) is a major agricultural pest in East Asia that causes considerable economic losses to the soybean crop each year. However, the molecular mechanisms governing the growth and development of R. pedestris have not been fully elucidated. In this study, the Illumina HiSeq6000 platform was employed to perform de novo transcriptome assembly and determine the gene expression profiles of this species across all developmental stages, including eggs, first-, second-, third-, fourth-, and fifth-instar nymphs, and adults. In this study, a total of 60,058 unigenes were assembled from numerous raw reads, exhibiting an N50 length of 2126 bp and an average length of 1199 bp, and the unigenes were annotated and classified with various databases, such as the Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG), and Gene Ontology (GO). Furthermore, various numbers of differentially expressed genes (DEGs) were calculated through pairwise comparisons of all life stages, and some of these DEGs were associated with immunity, metabolism, and development by GO and KEGG enrichment. In addition, 35,158 simple sequence repeats (SSRs) and 715,604 potential single nucleotide polymorphisms (SNPs) were identified from the seven transcriptome libraries of R. pedestris. Finally, we identified and summarized ten wing formation-related signaling pathways, and the molecular properties and expression levels of five wing development-related genes were analyzed using quantitative real-time PCR for all developmental stages of R. pedestris. Taken together, the results of this study may establish a foundation for future research investigating developmental processes and wing formation in hemimetabolous insects and may provide valuable data for pest control efforts attempting to reduce the economic damage caused by this pest.

Making one-sided exercise decisions: The influence of exercise-related cognitive errors

2016 ◽  
Vol 23 (9) ◽  
pp. 1240-1249 ◽  
Author(s):  
Sean R Locke ◽  
Lawrence R Brawley
Keyword(s):  
Decision Making ◽  
Information Processing ◽  
Relevant Information ◽  
Future Research ◽  
Cognitive Errors ◽  
Online Questionnaire ◽  
Cognitive Error ◽  
Biased Processing

Exercise-related cognitive errors reflect biased processing of exercise-relevant information. The purpose of this study was to examine whether differences existed between individuals reporting low and high exercise-related cognitive errors on information processed about a relevant exercise decision-making situation. In all, 138 adults completed an online questionnaire. The high exercise-related cognitive error group primarily focused on negative content about the situation compared to the low exercise-related cognitive error group who focused on both positive and negative content. The high exercise-related cognitive error group displayed biased processing of exercise information, as suggested by the cognitive errors model. Future research should examine whether biasing information processing caused by exercise-related cognitive errors can be modified and attenuated.

scholarly journals Prospects of Using High-Throughput Proteomics to Underpin the Discovery of Animal Host–Nematode Interactions

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 825
Author(s):  
Tao Wang ◽  
Robin Gasser
Keyword(s):  
Mass Spectrometry ◽  
High Throughput ◽  
Anthelmintic Resistance ◽  
Nematode Species ◽  
Economic Losses ◽  
Future Research ◽  
Parasitic Nematodes ◽  
Public Health Burden ◽  
Host Parasite Interactions ◽  
Host Parasite

Parasitic nematodes impose a significant public health burden, and cause major economic losses to agriculture worldwide. Due to the widespread of anthelmintic resistance and lack of effective vaccines for most nematode species, there is an urgent need to discover novel therapeutic and vaccine targets, informed through an understanding of host–parasite interactions. Proteomics, underpinned by genomics, enables the global characterisation proteins expressed in a particular cell type, tissue and organism, and provides a key to insights at the host–parasite interface using advanced high-throughput mass spectrometry-based proteomic technologies. Here, we (i) review current mass-spectrometry-based proteomic methods, with an emphasis on a high-throughput ‘bottom-up’ approach; (ii) summarise recent progress in the proteomics of parasitic nematodes of animals, with a focus on molecules inferred to be involved in host–parasite interactions; and (iii) discuss future research directions that could enhance our knowledge and understanding of the molecular interplay between nematodes and host animals, in order to work toward new, improved methods for the treatment, diagnosis and control of nematodiases.

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