Dynamic Crushing of All-Metallic Corrugated Panels Filled With Close-Celled Aluminum Foams

2015 ◽  
Vol 82 (1) ◽  
Author(s):  
B. Yu ◽  
B. Han ◽  
C. Y. Ni ◽  
Q. C. Zhang ◽  
C. Q. Chen ◽  
...  
Keyword(s):  
Aluminum Foam ◽  
Sandwich Panel ◽  
Dominant Role ◽  
Sandwich Panels ◽  
Rate Sensitivity ◽  
Aluminum Foams ◽  
Foam Filling ◽  
Plastic Hardening ◽  
Insight Into

Under quasi-static uniaxial compression, inserting aluminum foams into the interstices of a metallic sandwich panel with corrugated core increased significantly both its peak crushing strength and energy absorption per unit mass. This beneficial effect diminished however if the foam relative density was relatively low or the compression velocity became sufficiently high. To provide insight into the varying role of aluminum foam filler with increasing compression velocity, the crushing response and collapse modes of all metallic corrugate-cored sandwich panels filled with close-celled aluminum foams were studied using the method of finite elements (FEs). The constraint that sandwich panels with and without foam filling had the same total weight was enforced. The effects of plastic hardening and strain rate sensitivity of the strut material as well as foam/strut interfacial debonding were quantified. Three collapse modes (quasi-static, transition, and shock modes) were identified, corresponding to different ranges of compression velocity. Strengthening due to foam insertion and inertial stabilization both acted to provide support for the struts against buckling. At relatively low compression velocities, the struts were mainly strengthened by the surrounding foam; at high compression velocities, inertia stabilization played a more dominant role than foam filling.

Effects of aluminum foam filling on the low-velocity impact response of sandwich panels with corrugated cores

2018 ◽  
Vol 22 (4) ◽  
pp. 929-947 ◽  
Author(s):  
LL Yan ◽  
B Yu ◽  
B Han ◽  
QC Zhang ◽  
TJ Lu ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Sandwich Panel ◽  
Absorption Capacity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Energy Absorption Capacity ◽  
Core Member ◽  
Foam Filling ◽  
Foam Filled

In this study, a closed-cell aluminum foam was filled into the interspaces of a sandwich panel with corrugated cores to form a composite structure. The novel structure is expected to have enhanced foam-filled cores with high specific strength and energy absorption capacity. An out-of-plane compressive load under low-velocity impact was experimentally and numerically carried out on both the empty and foam-filled sandwich panels as well as on the aluminum foam. It is found that the empty corrugated sandwich panel has poor energy absorption capacity due to the core member buckling compared to that of the aluminum foam. However, by the filling of the aluminum foam, the impact load resistance of the corrugated panel was increased dramatically. The loading-time response of the foam-filled panel performs a plateau region like the aluminum foam, which has been proved to be an excellent energy absorption material. Numerical results demonstrated that the aluminum foam filling can decrease the corrugated core member defects sensitivity and increase its stability dramatically. The plastic energy dissipation of the core member for the foam-filled panel is much higher than that of the empty one due to the reduced buckling wavelength caused by the aluminum foam filling.

Structure and Deformation of Gradient Metal Foams Produced by Machining

2019 ◽  
Author(s):  
H. Qiao ◽  
T. G. Murthy ◽  
C. Saldana
Keyword(s):  
Aluminum Foam ◽  
Mechanical Performance ◽  
Metal Foams ◽  
Aluminum Foams ◽  
Open Cell ◽  
Computed Tomographic ◽  
Surface Gradient ◽  
Structure Changes

Abstract The effects of surface structure on mechanical performance for open-cell aluminum foam specimens was investigated in the present study. A surface gradient for pore structure and diameter was introduced into open cell aluminum foams by machining-based processing. The structure changes in the strut and pore network were evaluated by computed tomography characterization. The role of structure gradients in affecting mechanical performance was determined using digital volume correlation and in situ compression within the computed tomographic scanner. These preliminary results show that the strength of these materials may be enhanced through surface structural gradients.

Experimental and numerical study of buckling behavior of foam-filled honeycomb core sandwich panels considering viscoelastic effects

2020 ◽  
pp. 109963622097516
Author(s):  
M Safarabadi ◽  
M Haghighi-Yazdi ◽  
MA Sorkhi ◽  
A Yousefi
Keyword(s):  
Energy Absorption ◽  
Viscoelastic Properties ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Honeycomb Core ◽  
Buckling Behavior ◽  
Foam Filling ◽  
Foam Filled ◽  
Composite Face

Honeycomb sandwich panels are widely used in marine, aerospace, automotive and shipbuilding industries. High strength to weight and excellent energy absorption are features that make these structures unique. Foam filling the honeycomb core enhances the mechanical properties of sandwich panels considerably. In the present study, the buckling behavior of Nomex honeycomb core/glass-epoxy face sheet sandwich panel for both bare and foam-filled honeycomb core is investigated numerically and experimentally, considering the viscoelastic properties of the sandwich panel. Indeed, the viscoelastic properties of the composite face sheet and foam are determined by relaxation test and are implemented in ABAQUS using VUmat code. The finite element method is also performed using ABAQUS to model the buckling behavior of the sandwich panel incorporating both elastic and viscoelastic material behaviour. The effects of composite face sheet lay-up, core thickness, core cell size, and foam filling are also evaluated. The experimental and numerical results show that the foam increases the critical buckling load and energy absorption.

scholarly journals Effects of Aluminum Foam Filling on Compressive Strength and Energy Absorption of Metallic Y-Shape Cored Sandwich Panel

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1670
Author(s):  
Leilei Yan ◽  
Pengbo Su ◽  
Yagang Han ◽  
Bin Han
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Sandwich Panel ◽  
Sandwich Structures ◽  
Deformation Mode ◽  
Metallic Foam ◽  
Filling Material ◽  
Specific Strength ◽  
Foam Filling ◽  
Foam Filled

The design of lightweight sandwich structures with high specific strength and energy absorption capability is valuable for weight sensitive applications. A novel all-metallic foam-filled Y-shape cored sandwich panel was designed and fabricated by using aluminum foam as filling material to prevent core member buckling. Experimental and numerical investigation of out-of-plane compressive loading was carried out on aluminum foam-filled Y-shape sandwich panels to study their compressive properties as well as on empty panels for comparison. The results show that due to aluminum foam filling, the specific structural stiffness, strength, and energy absorption of the Y-shape cored sandwich panel increased noticeably. For the foam-filled panel, aluminum foam can supply sufficient lateral support to the corrugated core and vertical leg of the Y-shaped core and causes a much more complicated deformation mode, which cannot occur in the empty panel. The complicated deformation mode leads to an obvious coupling effect, with the stress–strain curve of the foam-filled panel much higher than those of the empty panel and aluminum foam, which were tested separately. Metallic foam filling is an effective method to increase the specific strength and energy absorption of sandwich structures with lattice cores, making it competitive in load carrying and energy absorption applications.

Structure and Deformation of Gradient Metal Foams Produced by Machining

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Haipeng Qiao ◽  
Tejas G. Murthy ◽  
Christopher Saldana
Keyword(s):  
Aluminum Foam ◽  
Mechanical Performance ◽  
Metal Foams ◽  
Aluminum Foams ◽  
Open Cell ◽  
Computed Tomographic ◽  
Surface Gradient ◽  
Structure Changes

The effects of surface structure on mechanical performance for open-cell aluminum foam specimens were investigated in the present study. A surface gradient for pore structure and diameter was introduced into open-cell aluminum foams by machining-based processing. The structure changes in the strut and pore network were evaluated by computed tomography characterization. The role of structure gradients in affecting mechanical performance was determined using digital volume correlation and in situ compression within the computed tomographic scanner. These preliminary results show that the strength of these materials may be enhanced through surface structural gradients.

scholarly journals Decoding the Kinetic Limitations of Plasmon Catalysis: The Case of 4-Nitrothiophenol Dimerization

2020 ◽  
Author(s):  
Wouter Koopman ◽  
Radwan M. Sarhan ◽  
Felix Stete ◽  
Clemens N. Z. Schmitt ◽  
Matias Bargheer
Keyword(s):  
Thermal Effects ◽  
Dominant Role ◽  
Relative Importance ◽  
New Approach ◽  
Multistep Reaction ◽  
Kinetics Of ◽  
Complex Organic ◽  
Insight Into ◽  
Unique Ability

Plasmon-mediated chemistry presents an intriguing new approach to photocatalysis. However, the reaction enhancement<br>mechanism is not well understood. In particular, the relative importance of plasmon-generated hot charges and<br>photoheating are strongly debated. In this article, we evaluate the influence of microscopic photoheating on the kinetics of<br>a model plasmon-catalyzed reaction: the light-induced 4-nitrothiophenol (4NTP) to 4,4’-dimercaptoazobenzene (DMAB)<br>dimerization. Direct measurement of the reaction temperature by nanoparticle Raman-thermometry demonstrated that<br>the thermal effect plays a dominant role in the kinetic limitations of this multistep reaction. On the same time, no reaction<br>is possible by dark heating to the same temperature. This shows that plasmon nanoparticles have the unique ability to<br>enhance several steps of complex tandem reactions simultaneously. These results provide insight into the role of hot<br>electron and thermal effects in plasmonic catalysis of complex organic reactions, which highly important for the ongoing<br>development of plasmon based photosynthesis. <br>

Quasi-Static Crushing of Aluminum Foam-Filled Thin-Walled Aluminum Tubes

2018 ◽  
Vol 933 ◽  
pp. 209-214
Author(s):  
Yang Yu ◽  
Zhuo Kun Cao ◽  
Min Li ◽  
Hong Jie Luo
Keyword(s):  
Cell Size ◽  
Energy Absorption ◽  
Aluminum Foam ◽  
Cell Structure ◽  
Peak Load ◽  
Aluminum Foams ◽  
Static Compression ◽  
Aluminum Tubes ◽  
Foam Filling ◽  
Foam Filled

The effect of aluminum foams with different cell structure on the quasi-static compression behavior and energy absorption of aluminum tubular structures was investigated. For comparison, empty tubes and aluminum foams with different cell structure were also tested, respectively. The results indicated that the value of crushing peak load of aluminum foam-filled tubes increases from 57.88% (1.94mm cell size) to 89.33% (1.22mm cell size) respectively compared with 2.83mm cell size. Splitting deformation of foam filling was found to effect in increasing the extra contact between the foam filling and the tube during progressive crushing, which increases the lateral compressive forces on the tubes. The energy absorption of aluminum foams filled aluminum tubes was also improved significantly due to the change of cell structure.

scholarly journals Compressive behavior and energy absorption capacity of unconstrained and constrained open-cell aluminum foams

2020 ◽  
Vol 29 ◽  
pp. 2633366X2092367
Author(s):  
Chengbing Li ◽  
Chunxing Li ◽  
Yazhou Wang
Keyword(s):  
Aluminum Foam ◽  
Dynamic Compression ◽  
Rate Sensitivity ◽  
Absorption Capacity ◽  
Compressive Behavior ◽  
Aluminum Foams ◽  
Energy Absorption Capacity ◽  
Open Cell ◽  
Hollow Structures ◽  
Practical Engineering

In practical engineering applications, while the open-cell aluminum foam as crash absorber is filled to the hollow structures, its deformation occurs under constrained stress boundaries. The experimental work was conducted to examine the effect of radial constraints on the mechanical behavior of the open-cell aluminum foam under quasi-static and dynamic compression. Results show that the radial constraints induce significant strain hardening of the open-cell aluminum foam. The open-cell aluminum foams tested with and without radial constraints show a clear strain rate sensitivity. The densification of the foam occurs earlier (showing lower densification strain) under radial constraints. The radial constraints enhance the energy absorbed per unit volume of the open-cell aluminum foam.

scholarly journals Science, Technology and the Supernatural in Contemporary Thai Novels

MANUSYA ◽  
2006 ◽  
Vol 9 (1) ◽  
pp. 38-50
Author(s):  
Pornvipa Watarachanakool
Keyword(s):  
Dominant Role ◽  
Science And Technology ◽  
Active Role ◽  
Human Beings ◽  
Contemporary Novels ◽  
Science Technology ◽  
Brighter Future ◽  
Insight Into ◽  
Role Of Local Cultures

As science and technology gain a high reputation and perform an increasingly dominant role in the present globalized era, old knowledge and wisdom, especially local forms, are fast disappearing. Will this trend necessarily bring about a brighter future for the whole world? Are science and technology trustworthy enough and safe enough for human beings to rely on without the other, dated, form of knowledge? These questions comprise the main interest of this paper, which endeavors to search for ideas, practices, and, also, expectations about the stated issues from Thai contemporary novels, in order to examine whether or not there is such a trend in Thai society, and what is the explanation. From literary and cultural anthropological perspectives, the findings seem to reflect that the Thai urban population are well aware of the increasing significance of science and technology and welcome them with enthusiasm. However, for the majority of the rural citizens, the information found presents a rather active role of local cultures and religion, which are closely related to beliefs in the supernatural. This paper is attempts to present some insight into this important issue.

scholarly journals Decoding the Kinetic Limitations of Plasmon Catalysis: The Case of 4-Nitrothiophenol Dimerization

2020 ◽  
Author(s):  
Wouter Koopman ◽  
Radwan M. Sarhan ◽  
Felix Stete ◽  
Clemens N. Z. Schmitt ◽  
Matias Bargheer
Keyword(s):  
Thermal Effects ◽  
Dominant Role ◽  
Relative Importance ◽  
New Approach ◽  
Multistep Reaction ◽  
Kinetics Of ◽  
Complex Organic ◽  
Insight Into ◽  
Unique Ability

Plasmon-mediated chemistry presents an intriguing new approach to photocatalysis. However, the reaction enhancement<br>mechanism is not well understood. In particular, the relative importance of plasmon-generated hot charges and<br>photoheating are strongly debated. In this article, we evaluate the influence of microscopic photoheating on the kinetics of<br>a model plasmon-catalyzed reaction: the light-induced 4-nitrothiophenol (4NTP) to 4,4’-dimercaptoazobenzene (DMAB)<br>dimerization. Direct measurement of the reaction temperature by nanoparticle Raman-thermometry demonstrated that<br>the thermal effect plays a dominant role in the kinetic limitations of this multistep reaction. On the same time, no reaction<br>is possible by dark heating to the same temperature. This shows that plasmon nanoparticles have the unique ability to<br>enhance several steps of complex tandem reactions simultaneously. These results provide insight into the role of hot<br>electron and thermal effects in plasmonic catalysis of complex organic reactions, which highly important for the ongoing<br>development of plasmon based photosynthesis. <br>

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