scholarly journals Shock Wave Attenuation Characteristics of Aluminum Foam Sandwich Panels Subjected to Blast Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jinglin Xu ◽  
Jianqing Liu ◽  
Wenbin Gu ◽  
Xin Liu ◽  
Tao Cao
Keyword(s):  
Shock Wave ◽  
Mild Steel ◽  
Polyvinylidene Fluoride ◽  
Sandwich Structure ◽  
Aluminum Foam ◽  
Wave Attenuation ◽  
Steel Structure ◽  
Steel Structures ◽  
Test Results ◽  
Attenuation Rate

Comparative experiments were conducted with two different structures to study the mechanism of aluminum foam sandwich attenuating blast shock wave. The sandwich structure is composed of “steel–aluminum foam–steel,” and the mild steel structure is composed of “steel–steel.” In the experiment, the polyvinylidene fluoride transducers were used to directly test the load of stress wave between different interfaces of sandwich and mild steel structures. The strain of back sheet was simultaneously measured using high-precision strain gauge. The accuracy of the test results was verified by Henrych’s formula. Experimental results show that the wave attenuation rate on the mild steel structure is only 11.3%, whereas the wave attenuation rate on the sandwich structure can exceed 90%. The interface effect is clearly a more crucial factor in the wave attenuation. The peak value of back sheet strain in the mild steel structure is much higher than the sandwich structure. The apparent overall “X” crushing band is produced in the aluminum foam core, and scanning electron microscope (SEM) observation clearly shows the collapse of the cell wall. Experiments on the sandwich structure with different aluminum foam densities indicate that increasing the relative density results in increased attenuation capability of the aluminum foam and decreased attenuation capability of the sandwich structure. Experiments on the sandwich structure with different aluminum foam thickness indicate that increasing the thickness results in increased attenuation capability of the aluminum foam and the sandwich structure.

APPLICABILITY OF A NEW SURFACE PREPARATION METHOD FOR STEEL STRUCTURE USING LASER

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Hiroshi Ogami ◽  
Katashi Fujii ◽  
Yukio Manabe ◽  
Kohei Ota ◽  
Asuo Yonekura
Keyword(s):  
Preparation Method ◽  
Surface Condition ◽  
Surface Preparation ◽  
Steel Structure ◽  
Steel Structures ◽  
Laser Cleaning ◽  
Coating Film ◽  
Test Results ◽  
Corrosion Prevention ◽  
Accelerated Corrosion

Surface preparation is very important in re-painting of steel structures so as to extend the effective term of corrosion prevention. Though grinding or blasting have been widely used to remove rust and old coating film on steel surface, both these methods have difficulty in completion of rust-removal and cause some problems such as dust scattering, noise, etc. In order to solve these problems, this paper presents the laser cleaning method which instantaneously sublimes/evaporates the rust on the surface of steel structure. The authors investigate the effects and the applicability of laser cleaning using the specimens made by accelerated corrosion method. The test results confirmed that the laser cleaning can remove the rust almost much as using sand blast, and the salt on the surface of steel can also be evaporated as good as the rust. Moreover, this method seems can be applied on wet surface condition because the moisture and water on the surface of steel can also be evaporated.

scholarly journals THE HEATING RATE IMPACT ON PARAMETERS CHARACTERISTIC OF STEEL BEHAVIOUR UNDER FIRE CONDITIONS

2006 ◽  
Vol 12 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Zoja Bednarek ◽  
Renata Kamocka
Keyword(s):  
Heating Rate ◽  
Steel Structure ◽  
Steel Structures ◽  
Absolute Temperature ◽  
Strength Analysis ◽  
Test Results ◽  
Heating Rates ◽  
Linear Temperature ◽  
Strength Tests

The behaviour of steel structure components within a high temperature field depends not only on the absolute temperature, but also on the temperature vs time function and on the heating rate, dT/dτ. The research objective is the determination of the heating rate impact on selected strength parameters of structural steels. Tests were performed under conditions of a linear temperature increase with different heating rates and with a constant stress value, σ/fy . After strength tests, the samples were subjected to metallography. Test results proved that the heating rate makes a significant impact on parameters that determine the steel structure bearing capacity at higher temperatures and that the heating rate should be accounted for in the strength analysis of steel structures exposed to high temperatures.

scholarly journals Indoor Test System for Liquid CO2 Phase Change Shock Wave Pressure with PVDF Sensors

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2395
Author(s):  
Xing Huang ◽  
Qiyue Li ◽  
Xin’ao Wei ◽  
Xiaoxiao Yang ◽  
Dayou Luo ◽  
...  
Keyword(s):  
Shock Wave ◽  
Phase Change ◽  
Polyvinylidene Fluoride ◽  
High Reliability ◽  
Test System ◽  
Axial Distance ◽  
Test Results ◽  
Wave Pressure ◽  
Shock Wave Pressure ◽  
Test Points

Liquid carbon dioxide phase change fracturing technology (LCPCFT) has been widely used in engineering blasting due to the advantage of no flames, and no toxic and harmful gas. However, few studies have been conducted on the acquisition of shock wave pressure and its loading characteristics, which are key parameters in fracturing. Referring to the CO2 in-situ fracturing technology, an indoor test system for shock wave pressure generated during LCPCFT has been built, with a protected polyvinylidene fluoride (PVDF) piezoelectric sensor. Then three verification experiments with different radial distances between the fracturing tube and test points were carried out on the test system, and in each experiment, four PVDF sensors as four test points were arranged with different axial distance from the detonating point to test the pressure distribution. The experimental results show that when the radial distance between the fracturing tube and test points is not too large (≤345 mm), the pressure generated during LCPCFT is approximately uniformly distributed within the axial length of the fracturing tube, but when it is relatively large (≈895 mm), the results between different test points are in a certain degree of dispersion. And finally, this paper uses the intraclass correlation coefficient (ICC) and coefficient of variation (CV) of peak pressure and impulse to process the test results to evaluate the reliability and stability of the test system. Evaluation results show that the test results are in good consistency. The test system in this paper has good stability and high reliability. The test system provides a useful tool for accurately obtaining the shock wave pressure, which is helpful for further research on LCPCFT.

Numerical Analysis on Steel-Kevlar-Steel Sandwich Structure under Contact Explosion

2013 ◽  
Vol 681 ◽  
pp. 281-285
Author(s):  
Ji Feng Wei ◽  
Guo Shan Yang ◽  
Yuan Li ◽  
Shu Shan Wang
Keyword(s):  
Nonlinear Dynamics ◽  
Shock Wave ◽  
Sandwich Structure ◽  
Peak Pressure ◽  
Damage Zone ◽  
Steel Structure ◽  
Destruction Process ◽  
Impact Performance ◽  
Contact Explosion ◽  
Transmission And Reflection

The damage characteristics of the steel-Kevlar-steel structure are studied by nonlinear dynamics software. The whole destruction process of the sandwich structure is simulated. Moreover, the transmission and reflection of the shock wave in the structure are analyzed. It shows that the damage zone of the structure is just under the explosive. It is significantly different from the damage under non-contact explosion. The composite material has an effect on the spread of the shock wave, and effectively reduces the peak pressure. The sandwich structure has a good anti-impact performance. The results help to design and assess blast-resistant structures under contact explosion.

scholarly journals Analysis of the Cracking Mechanism of an Elliptical Bipolar Linear-Shaped Charge Blasting

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bo Wu ◽  
Han Wei ◽  
Shixiang Xu ◽  
Guowang Meng ◽  
Zhen Huang ◽  
...  
Keyword(s):  
Shock Wave ◽  
Stress Wave ◽  
Wave Attenuation ◽  
Shaped Charge ◽  
Propagation Length ◽  
Energy Accumulation ◽  
Attenuation Rate ◽  
Linear Shaped Charge ◽  
Initial Shock ◽  
Cracking Mechanism

This study investigates the cracking mechanism of an elliptical bipolar linear-shaped charge blasting via theoretical analysis, experimentation, and numerical simulation. The results show that in the shaped charge blasting, due to the effect of the shaped jet in the direction of the shaped energy, a certain initial crack length is formed. In the action phase of the stress wave, the energy accumulation direction reduces the load required for crack initiation and propagation. The crack propagation length generated in the energy accumulation direction is greater than the nonenergy accumulation direction. The load value of the initial shock wave in the shaped energy direction is significantly greater, by about 1.64 times than the nonshaped energy direction, and the peak load acting time is earlier than the nonshaped energy direction. A large amount of impact explosion energy is consumed in the area close to the charged energy explosion due to the crushing area, regardless of the charged or noncharged energy direction. In the energy accumulation direction, the shock wave attenuation rate is faster in the near explosion area and the stress wave attenuation rate is slower in the mid and far areas of the explosion. The difference in the explosion load in the mid and far areas is small. In the nonconcentrated direction, owing to the reflected compression wave, the second stress peak appears in the nonconcentrated direction. However, its value is smaller than that of the initial shock wave peak.

Research and Simulation on Strengthening Steel Structure with Carbon Fiber Sheet

2012 ◽  
Vol 232 ◽  
pp. 82-85
Author(s):  
Yang Hou Chen
Keyword(s):  
Carbon Fiber ◽  
Concrete Structures ◽  
Steel Structure ◽  
Steel Structures ◽  
Test Results ◽  
Element Analysis ◽  
Cfrp Composite ◽  
Fiber Sheet ◽  
Strengthening Technique ◽  
Carbon Fiber Sheet

Carbon Fiber-Reinforced Polymer(CFRP) Composite Sheets Have Gained Popularity as a Viable Strengthening Technique for Fractured Concrete Structures. the Behavior of Carbon Fiber Sheet Materials to Cracked Steel Structures Is Quite Different from that of Concrete Structures. More and More Attention Are Paid to Research on Strengthening Steel Structure with Carbon Fiber Sheet. this Paper Presents the Study on the Steel Structure Bonded with Carbon Fiber Sheets. the Infinite Element Analysis Software ANSYS Is Used to Analyze the Effects of Strengthening a Steel Structure. and the Test Results of Crack Specimens Strengthened by Carbon Fiber Sheet Are Given. the Finite Element Results and Test Results Show that the Using of Carbon Fiber Sheet Can Improve Load Bearing of Structure and its Fatigue Life.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

scholarly journals A New Approach for Cylindrical Steel Structure Deformation Monitoring by Dense Point Clouds

2021 ◽  
Vol 13 (12) ◽  
pp. 2263
Author(s):  
Dongfeng Jia ◽  
Weiping Zhang ◽  
Yuhao Wang ◽  
Yanping Liu
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Relative Deformation ◽  
Structure Deformation ◽  
Single Time ◽  
Cylindrical Steel ◽  
Cylinder Fitting

As fundamental load-bearing parts, the cylindrical steel structures of transmission towers relate to the stability of the main structures in terms of topological relation and performance. Therefore, the periodic monitoring of a cylindrical steel structure is necessary to maintain the safety and stability of existing structures in energy transmission. Most studies on deformation analysis are still focused on the process of identifying discrepancies in the state of a structure by observing it at different times, yet relative deformation analysis based on the data acquired in single time has not been investigated effectively. In this study, the piecewise cylinder fitting method is presented to fit the point clouds collected at a single time to compute the relative inclination of a cylindrical steel structure. The standard deviation is adopted as a measure to evaluate the degree of structure deformation. Meanwhile, the inclination rate of each section is compared with the conventional method on the basis of the piecewise cylinder fitting parameters. The validity and accuracy of the algorithm are verified by real transmission tower point cloud data. Experimental results show that the piecewise cylinder fitting algorithm proposed in this research can meet the accuracy requirements of cylindrical steel structure deformation analysis and has high application value in the field of structure deformation monitoring.

A Framework to Support the Optimization of Modularized Oil and Gas Structures

2018 ◽  
Author(s):  
Vincenzo Castorani ◽  
Paolo Cicconi ◽  
Michele Germani ◽  
Sergio Bondi ◽  
Maria Grazia Marronaro ◽  
...  
Keyword(s):  
Lead Time ◽  
Oil And Gas ◽  
Steel Structure ◽  
Steel Structures ◽  
Modular System ◽  
Test Case ◽  
Plant Design ◽  
Conceptual Study ◽  
A Current ◽  
Gas Plants

Modularization is a current issue in the context of plant design. A modular system aims to reduce lead time and cost in design phases. An oil & gas plant consists of many Engineered-To-Order solutions to be submitted and approved during the negotiation phase. In this context, design tools and methods are necessary to support the design life cycle from the conceptual study to the detailed project. The paper proposes an approach to optimize the design of modularized oil & gas plants with a focus on the related steel structures. A test case shows the configuration workflow applied to a modular steel structure of about 400 tons. The modularized layout has been optimized using genetic algorithms. A Knowledge Base has been described to support the configuration phase related to the conceptual design. Design rules and metrics have been formalized from the analysis of past solutions.

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