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Guangzhou, China

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Guangzhou, China
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Luo X.,PLA Air Force Aviation University | Xu J.,PLA Air Force Aviation University | Xu J.,Northwest University, China | Zhu J.,PLA Air Force Aviation University | And 3 more authors.
Thin-Walled Structures | Year: 2015

A numerical study is made to investigate the energy absorbing rule of thin-walled metal circular tube made of three different materials (steel, copper, aluminum) by using response surface methodology (RSM). At the same time, the application prospect of RSM in terms of the research on the energy absorption rule of energy absorption structure can be explored. The test result shows that, the compression process of thin-walled metal circular tube can be divided into three stages: elastic stage, yielding plateau stage, compact stage; To get the greatest value of average plateau force (APF), a tube with a shorter height and thicker wall should be adopted; To get the greatest length energy absorption (LEA), a tube with thicker wall should be adopted and the ratio of its height and diameter should be as big as possible; To get the greatest specific energy absorption (SEA), a tube with a thicker wall should be adopted and the ratio between its height and diameter should be as big as possible. Thus, it can be seen that, RSM is an advanced experiment design method, and it can be widely used in the research on the energy absorption characteristics of thin-walled metal circular tube and has a promising application prospect in the development of new energy absorbing material and structure. © 2015 Elsevier Ltd. All rights reserved.


Luo X.,PLA Air Force Aviation University | Xu J.,PLA Air Force Aviation University | Xu J.,Northwest University, China | Su H.,PLA Air Force Aviation University | And 2 more authors.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2014

C30 highly fluidized geopolymer concrete(HFGC) was prepared by using slag and fly ash as raw materials and NaOH and Na2CO3 as alkaline activation agent. The strength properties of HFGC under impact loading, including dynamic splitting-tensile and compressive strength, were studied by using φ100 split Hopkinson pressure bar(SHPB) apparatus improved with the pulse shaper technique. The results indicate that dynamic strength properties of HFGC exhibit strong strain rate dependence; for HFGC, strain rate sensitivity threshold under dynamic splitting-tensile condition is 5.027s-1, and under dynamic compressive condition that is 28.89s-1, the strain rate sensitivity of dynamic splitting-tensile strength is higher than that of dynamic compressive strength; the qualitative trend of dynamic strength properties of HFGC are in accord with that of normal concrete, but compared with normal concrete, the strain rate sensitivity of HFGC becomes even higher because of polycondensed network structure, and that can effectively develop the overall strength properties under impact loading. Thus it can be seen that HFGC is strain rate sensitive.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Nie L.,PLA Air Force Aviation University | And 3 more authors.
Composite Structures | Year: 2015

The present work focuses on the quasi-static axial crush performance of the thin-walled tubes filled with hollow metal spheres (TWT-HMS) and their individual components (thin-walled tubes and hollow metal spheres) under axial compressive loads. All structures were compared in terms of the load-displacement and/or load-strain curves, energy absorption and energy absorbing efficiency curves. The results indicate that hollow metal spheres and thin-walled tubes are promising energy absorbing materials. The hollow metal spheres improve the axial bearing capability of thin-walled tube, and the biggest improvement scale can be 300%; due to the superimposed effect, TWT-HMS has more excellent properties than the hollow metal sphere and thin-walled tube. Thus, TWT-HMS is an energy absorbing structure with excellent properties and it has a promising application prospect. © 2015 Elsevier Ltd.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Li W.,Airport Office
Functional Materials Letters | Year: 2015

Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress-strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress-strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering. © 2015 World Scientific Publishing Company.


Xin L.,PLA Air Force Aviation University | Jin-yu X.,PLA Air Force Aviation University | Weimin L.,Airport Office | Zhi-kun W.,PLA Air Force Aviation University
Journal of Materials in Civil Engineering | Year: 2015

Cementitious materials, ceramic aggregates, and fiber are used as basic materials; ceramics cement-based porous material (CCPM) and basalt fiber-reinforced ceramics cement-based porous material (BFRCCPM) are prepared on the basis of Closest Packing Theory. After the tests, the internal relation between the average change rate of incident energy and the physical essence of the ensemble damage modes is discussed, and the change law of energy is probed. BFRCCPM's compression energy properties during the dynamic deformation damage process are analyzed, and based on that, the effect of basalt fiber on the dynamic damage characteristics are studied. Results show that the damage level and energy absorption of CCPM and BFRCCPM get more serious or increase with the average change rate of incident energy; the damage level of BFRCCPM is obviously lower than that of CCPM. Moreover, BFRCCPM possesses better energy absorbing properties than CCPM. This advantage is more obvious when the average change rate of incident energy is very high; the impact-damage resistance of CCPM and BFRCCPM increases with impact strength. The impact-damage resistance of BFRCCPM is stronger than that of CCPM. Thus it can be seen that basalt fiber can prevent microdamages from developing and evolving, which can enhance the impact-damage resistance of CCPM. © 2014 American Society of Civil Engineers.


Xin L.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Li W.,Airport Office | Bai E.,PLA Air Force Aviation University
Materials Letters | Year: 2014

NaOH and sodium silicate-activated slag and fly ash based geopolymer concrete (NSSFGC) and NaOH and Na2CO3-activated slag and fly ash based geopolymer concrete (NNSFGC) with strength grades of C30 were prepared, the dynamic compressive deformation behavior under impact loading was studied contrastly. The results indicate that, the compressive deformation of NSSFGC is greater than that of NNSFGC in the stage of compaction, which indicates that the volume of microdefect of NSSFGC is greater than that of NNSFGC; the elasticity modulus of NNSFGC is larger than that of NSSFGC; NSSFGC has excellent deformation performance. Thus it can be seen that, alkali-activator types have a big impact on the dynamic compressive deformation behavior of GC, and compared to the alkali-activator prepared with NaOH and Na2CO3, the alkali-activator prepared with NaOH and sodium silicate can be beneficial to give full play to deformation property; so it is better to prepare GC with NaOH and sodium silicate, when used in the Earthquake Engineering. © 2014 Elsevier B.V.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Li W.,Airport Office
RSC Advances | Year: 2015

In order to develop a new energy-absorbing material by using solid waste, a basalt fiber reinforced lightweight aggregate-geopolymer based cellular material (BFRLGCM) is prepared. A quasi-static compression experiment was carried out, the stress-strain curves were calculated, the ideal energy-absorbing efficiency was analyzed and the material's prospects and feasibility of application have been explored. The results show that: the fiber reinforced cellular material prepared on the basis of Dense Packing Theory has successively sized pore structures; the stress-strain curve of the smaller specimen has three stages: the elastic stage, yielding plateau stage, and dense stage, and the dense strain is 0.646; the greatest value of the ideal energy-absorbing efficiency of BFRLGCM is 90.4%, which suggests BFRLGCM has excellent energy-absorbing properties. Thus it can be seen that the raw materials for BFRLGCM are abundant, the manufacturing cost is low, and BFRLGCM is easy and simple to make. With high plasticity, low density and excellent energy-absorbing features, BFRLGCM is a promising energy-absorbing material especially for use in civil defense engineering. What's more, BFRLGCM has unique economical, social and environmental advantages, and the application of BFRLGCM can improve the utilization of solid waste, turning waste into wealth and so realizing a double win. © The Royal Society of Chemistry 2015.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Bai E.-L.,PLA Air Force Aviation University | Li W.,Airport Office
Materials and Design | Year: 2014

Cementitious materials and ceramic aggregates used as basic materials, ceramics-cement based porous material (CCPM) has been prepared. Φ100. mm SHPB has been improved by wave shaping techniques, which can guarantee the availability of the tests. Quasi static compression test and impacting compression test have been carried out, the damage process of specimen under loading has been analyzed, and mechanics parameters under different strain rates have been obtained, moreover, based on this, the mechanical properties of CCPM under impact loading, including strength property, deformation property, impacting toughness, have been studied, in addition, the prospect of CCPM's application has also been discussed. The results indicate that, the quasi static and impact compressive stress-strain curve of CCPM includes a strain plateau, which helps to better absorb energy; the dynamic strength increase factors of CCPM and the natural logarithm of relative strain rate are of a linear relationship; the relationship between the dynamic peak strain increase factors and the related strain rate can be described with an exponential linear, which shows obvious "damage softening" effect; with the increase of average strain rate, the impacting toughness of CCPM gets strengthened continuously and the impact toughness indexes are in a logarithm relationship with strain rate; CCPM is more strain rate sensitive than ordinary cement based composite materials. Thus it can be seen, CCPM possesses the advantageous mechanical properties of both porous materials and ordinary cement based composite materials. Besides, the material is easy to prepare and simple to make. Along with its high plasticity and low density, CCPM has a promising future to perform its potential advantages in engineering, especially in national defense engineering. © 2013 Elsevier Ltd.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Bai E.-L.,PLA Air Force Aviation University | Li W.,Airport Office
Construction and Building Materials | Year: 2014

Ceramics-cement based porous material (CCPM) and basalt fiber reinforced ceramics-cement based porous material (BFRCCPM) have been prepared. The quasi-static compression test and impact compression test of both CCPM and BFRCCPM have been made and the energy-absorption indicators under different strain rate have been obtained. The energy-absorbing features of them have been comparatively analyzed and the effect of basalt fiber has been comparatively studied. The results show: under quasi-static compression state, the peak toughness and full toughness increase continuously with strain rate. Under the same strain rate, the peak toughness of BFRCCPM are obviously higher than that of CCPM. It is because basalt fiber can increase the peak toughness and full toughness. During impact compression stage, the peak toughness and specific energy absorption are highly strain rate sensitive and increase continuously with it. Basalt fiber has obvious improving effect on both peak toughness and full toughness. During impact compression state, the more energy the specimen absorbs, the more seriously it is damaged. BFRCCPM is comparatively slightly damaged given the same amount of absorbed energy. It is because the important effect of the basalt fiber. So, it can be concluded that basalt fiber can improve the energy-absorbing ability of porous material and has a promising future in the feature improving field. © 2014 Elsevier Ltd. All rights reserved.


Luo X.,PLA Air Force Aviation University | Xu J.-Y.,PLA Air Force Aviation University | Xu J.-Y.,Northwest University, China | Bai E.-L.,PLA Air Force Aviation University | Li W.,Airport Office
Construction and Building Materials | Year: 2013

Slag and fly ash were used in the fabrication of geopolymer concrete (GC), sodium hydroxide (NaOH, NH) and sodium carbonate (Na2CO3, NC) were used for slag and fly ash activation, then highly fluidized C30 GC was prepared. Φ100 mm SHPB apparatus was improved by the pulse shaper technique, and the dynamic stress equilibrium and nearly constant strain rate loading were realized. Based on this, the dynamic compressive mechanical properties, including strength, deformation and energy absorption property, of GC were tested, in addition, the mechanism of dynamic properties of the GC was primarily analyzed. The results indicate that, dynamic compressive mechanical properties of GC exhibit strong strain rate dependency; dynamic strength increase factor increases approximately linearly with the logarithm of the average strain rate; the peak strain increases firstly and decreased later with the rising of stain rate, 66.7 s-1 is the critical strain rate between impact toughness and impact embrittlement; from an energy perspective, the correlation between specific energy absorption and stain rate is obvious and the equation type is binomial curve. © 2013 Published by Elsevier Ltd.

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