scholarly journals Damage Analysis of Concrete Structure under Multidirectional Shaped Charge Blasting Using Model Experiment and Ultrasonic Testing

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Dunwen Liu ◽  
Jianjun Zhang ◽  
Yu Tang ◽  
Yinghua Jian ◽  
Caiwu Cai
Keyword(s):  
Energy Distribution ◽  
Ultrasonic Testing ◽  
Shaped Charge ◽  
Test Results ◽  
Rock Fracturing ◽  
New Approach ◽  
Damage Law ◽  
Probability And Statistics ◽  
Concrete Model ◽  
Blasting Method

Quantitatively analyzing multidirectional shaped charge blasting energy distribution and improving the rock-fracturing efficiency have been a challenging problem in blasting and civil engineering. In this work, we carry out four groups of concrete model experiments using ultrasonic testing, comparing conventional blasting, and multidirectional shaped charge blasting. Then, the probability and statistics method is used to quantitatively analyze the blasting damage and the energy distribution. The test results show that ultrasonic testing and statistics model can quantitatively evaluate the damage law and energy distribution of blasting. By comparing with conventional blasting method, the multidirectional shaped charge blasting with V-shaped multidirectional shaped energy groove has achieved the effect of energy accumulation. It increases the distribution of energy in the rock crack district, increases the blasting damage range, and improves the rock-fracturing efficiency of blasting. The V-shaped multidirectional shaped energy groove can be used as a new approach for rock fracturing in similar projects.

scholarly journals LiDAR-Based Glass Detection for Improved Occupancy Grid Mapping

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2263
Author(s):  
Haileleol Tibebu ◽  
Jamie Roche ◽  
Varuna De Silva ◽  
Ahmet Kondoz
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
Light Detection And Ranging ◽  
Test Results ◽  
New Approach ◽  
Occupancy Grid ◽  
Laser Scanners ◽  
Novel Method ◽  
Occupancy Grid Mapping ◽  
Cartesian Coordinate

Creating an accurate awareness of the environment using laser scanners is a major challenge in robotics and auto industries. LiDAR (light detection and ranging) is a powerful laser scanner that provides a detailed map of the environment. However, efficient and accurate mapping of the environment is yet to be obtained, as most modern environments contain glass, which is invisible to LiDAR. In this paper, a method to effectively detect and localise glass using LiDAR sensors is proposed. This new approach is based on the variation of range measurements between neighbouring point clouds, using a two-step filter. The first filter examines the change in the standard deviation of neighbouring clouds. The second filter uses a change in distance and intensity between neighbouring pules to refine the results from the first filter and estimate the glass profile width before updating the cartesian coordinate and range measurement by the instrument. Test results demonstrate the detection and localisation of glass and the elimination of errors caused by glass in occupancy grid maps. This novel method detects frameless glass from a long range and does not depend on intensity peak with an accuracy of 96.2%.

scholarly journals Studi Eksperimental Kekuatan dan Perilaku Sambungan Kolom pada Struktur DfD (Design for Disassembly)

2016 ◽  
Vol 21 (2) ◽  
pp. 113
Author(s):  
Intan Fitriani ◽  
Sukamta Sukamta ◽  
Ilham Nurhuda
Keyword(s):  
Normal Force ◽  
Precast Concrete ◽  
Failure Mechanisms ◽  
Test Results ◽  
New Approach ◽  
Column Structure ◽  
Design Loads ◽  
Building Components ◽  
Building System ◽  
Plate Connection

DfD building system is a new approach in construction. Using DfD building system can reduce construction waste and reuse building components. This research examines the strength and behaviour of DfD column connections. Two types column connections were studied.The first connection employed H shaped steel elements bolted to the column while the second connection was bolt and plate connection. The behavior of columns with connections was compared to that of without connection. This study was carried out to investigate the strength, crack patterns, and failure mechanisms of precast concrete with dry joint on DfD column structure. All specimens were subject to normal force applied with an eccentricity of 67 mm. The test results indicate that both columns with connections were able to withstand design loads. This study also confirmed that the shear strength calculation of corbel based on SNI 03-2847-2002 section 13.9 was conservative to use as the value was still smaller than that obtained from this experiment.

scholarly journals The Influence of the Permeability of the Fractures Zone Around the Heading on the Concentration and Distribution of Methane

2019 ◽  
Vol 12 (1) ◽  
pp. 16 ◽  
Author(s):  
Magdalena Tutak
Keyword(s):  
Ventilation System ◽  
Organizational Factors ◽  
Primary Objective ◽  
Test Results ◽  
Ansys Fluent ◽  
New Approach ◽  
Model Based ◽  
Coal Beds ◽  
Air Stream ◽  
Fluent Software

One of the main problems related to the excavation of dog headings in coal beds is the emission of methane during this process. To prevent the occurrence of dangerous concentration levels of this gas, it is necessary to use an appropriate ventilation system. The operation effectiveness of such a system depends on a number of mining, geological, technical and organizational factors. One of them includes the size and permeability of the fractures zone formed around the excavated dog heading. The primary objective of the paper is to determine the influence of this zone on the ventilation parameters, including the concentration and distribution of methane in the excavated dog heading. In order to achieve the assumed objective, multivariate model-based tests were carried out, which reproduce a real-world dog heading. Literature data and test results in actual conditions were used to determine the size and permeability of the fractures zone around the excavated heading. These data served as the basis to develop a model of the region under analysis and adopt boundary conditions. The analyses were carried out for four permeability values of the fractures zone and for two volumetric flow rates of the air stream supplied to the heading. The results were used to determine the influence of the fractures zone on the distribution and concentration of methane in the heading under analysis. The model-based tests were performed using ANSYS Fluent software. The idea to take into account the fractures zone around the heading represents a new approach to the analysis of ventilation parameters in underground mine headings. The results clearly indicate that this zone affects the ventilation parameters in the heading, including the distribution and concentration of methane. The knowledge obtained from the tests should be used to optimize the ventilation process of dog headings. All authors have read and agreed to the published version of the manuscript.

scholarly journals Test results on a new approach for fitting “ski-slope” hearing losses

1999 ◽  
Vol 52 (6) ◽  
pp. 68-69
Author(s):  
Birgitta Gabriel ◽  
Birger Kollmeier
Keyword(s):  
Test Results ◽  
New Approach

A general concrete model in hydrocodes: Verification and validation of the Riedel–Hiermaier–Thoma model in LS-DYNA

2017 ◽  
Vol 8 (1) ◽  
pp. 58-85 ◽  
Author(s):  
Christoph Grunwald ◽  
Benjamin Schaufelberger ◽  
Alexander Stolz ◽  
Werner Riedel ◽  
Thomas Borrvall
Keyword(s):  
High Strength ◽  
Single Element ◽  
Test Results ◽  
Pressure Loading ◽  
Geological Materials ◽  
Wide Range ◽  
Simulation Results ◽  
Material Library ◽  
Concrete Model ◽  
Very High

The Riedel–Hiermaier–Thoma model, which is available in ANSYS Autodyn since 2000 as a description of concrete and similar geological materials in highly dynamic loading situations, has recently been implemented in the multi-purpose Finite Element code LS-DYNA. This article gives a brief overview of the physical details and verifies the new implementation by comparing single element test results with the established Autodyn code. Four real cases, ranging from low to very high pressure loading by impact, penetration and blast, are used to demonstrate thereafter the validity of the model in a wide range of applications. Simulation results from both codes are compared to experimental data at several occasions. Although slight differences between the implementations are observed, the overall agreement, both between the codes and with experiments, is very good. The systematic work in this publication demonstrates that the Riedel–Hiermaier–Thoma model is a useful addition to the LS-DYNA material library and shall motivate research to apply the model over a wide range of applications. A comprehensive, physically derived dataset is provided for a C70/85 high-strength concrete used in one validation case.

The Experimental Study of Ultrasonic Testing Prestressed Bellows Pore Grouting Quality

2014 ◽  
Vol 711 ◽  
pp. 461-468 ◽  
Author(s):  
Shao Lin Zhou ◽  
Feng Zhang ◽  
Yuan Cao
Keyword(s):  
Experimental Study ◽  
Ultrasonic Testing ◽  
Concrete Slab ◽  
Ultrasonic Method ◽  
Test Results ◽  
Concrete Panels ◽  
Head Waves ◽  
Different Thickness ◽  
Regular Patterns

The ultrasonic method can be used for testing and analyzing the pore size of concrete. By studying the spectrum curves which is formed by ultrasonic transmitting at different thickness concrete panels can we get different time regular patterns of head waves formed by ultrasonic going through homogeneous concrete, compact grouting pore, grouting incompact pore, not grouting pore. All these provide a basis for predicting prestressed bellows pore grouting quality and judging whether there is interspace in pore. By artificially setting defects in bellows pore, for example, filling the pore to completely empty, 1/4 compact, 1/2 compact, 3/4 compact, fully compact and then embedding them in a concrete slab for ultrasonic testing. Test results show that the ultrasonic method can effectively evaluate the grouting quality of prestressed bellows pore.

A New Approach to Probability in Engineering Design and Optimization

1984 ◽  
Vol 106 (1) ◽  
pp. 5-10 ◽  
Author(s):  
J. N. Siddall
Keyword(s):  
Probability Density ◽  
Engineering Design ◽  
Probability Distributions ◽  
Probability Density Functions ◽  
Density Functions ◽  
New Approach ◽  
Design And Optimization ◽  
Evolutionary Technique ◽  
Probability And Statistics

The anomalous position of probability and statistics in both mathematics and engineering is discussed, showing that there is little consensus on concepts and methods. For application in engineering design, probability is defined as strictly subjective in nature. It is argued that the use of classical methods of statistics to generate probability density functions by estimating parameters for assumed theoretical distributions should be used with caution, and that the use of confidence limits is not really meaningful in a design context. Preferred methods are described, and a new evolutionary technique for developing probability distributions of new random variables is proposed. Although Bayesian methods are commonly considered to be subjective, it is argued that, in the engineering sense, they are really not. A general formulation of the probabilistic optimization problem is described, including the role of subjective probability density functions.

scholarly journals Use of Graphene for Shaped Charge Liner Materials

2018 ◽  
Vol 9 (3) ◽  
pp. 15-28 ◽  
Author(s):  
Tomasz MAJEWSKI ◽  
Adam JACKOWSKI
Keyword(s):  
Process Parameters ◽  
Copper Powder ◽  
Pure Copper ◽  
Shaped Charge ◽  
Powder Materials ◽  
Test Results ◽  
Explosive Material ◽  
Research Task ◽  
Materials Used ◽  
Coated Powder

The paper presents some selected results of tests performed as part of a research task titled "Use of graphene and new multilayer explosive material technologies in shaped charge liner materials". The main aim of the experiments was to test the possibilities of using graphene as an addition to materials used for shaped charge liner production. The primary factors that need to be considered when selecting materials for shaped charge liners are presented. The paper contains a description of the powder materials used, as well as a description of the primary manufacturing steps, encompassing the powder blend preparation, pressing and sintering operations. The results of experiments intended to determine the effects of selected manufacturing process parameters on the porosity of the resulting compacts and sinters are shown, both for products made of pure copper powder and graphene-coated powder. Subsequently, test results for manufacturing of liners made using copper powder pressed using the die and isostatic methods are presented. Liners made of copper powder blends with a varying content of graphene-coated copper powder were also manufactured, and densities and porosities of the resulting sinters were compared.

scholarly journals Validation of a New Aluminum Honeycomb Crush Model With Dynamic Impact Tests

2007 ◽  
Author(s):  
Terry Hinnerichs ◽  
William Scherzinger ◽  
Mike Nielsen ◽  
Tom Carne ◽  
Eric Stasiunas ◽  
...  
Keyword(s):  
Finite Element ◽  
Rate Sensitivity ◽  
Element Model ◽  
Test Results ◽  
Dynamic Impact ◽  
New Approach ◽  
Test Parameters ◽  
Aluminum Honeycomb ◽  
Impact Simulations ◽  
Constitutive Parameters

This paper describes a process for validating a new constitutive model for large, high strain-rate deformation of aluminum honeycomb, called the Honeycomb Crush Model (HCM). This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. The HCM has been implemented in the transient dynamic Presto finite element code for dynamic impact simulations. The HCM constitutive parameters were identified based on Presto finite element models that were used to simulate uniaxial and biaxial crush tests of 38 lb/ft3 aluminum honeycomb and reported in an earlier paper. This paper focuses on validating the HCM in the Presto code for application to impact situations that have honeycomb crush velocities up to 85 ft/sec. Also, a new approach for incorporating rate sensitivity into the model is described. A two-stage energy absorber with integrated aluminum honeycomb is described as the configuration for dynamic impact validation experiments. The test parameters and finite element model will be described along with the uncertainty quantification that was done and propagated through the model. Finally, correlation of model predictions and test results will be presented using an energy based validation metric.

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