Effects of foam core density and face-sheet thickness on the mechanical properties of aluminum foam sandwich

Chang Yan,Xuding Song 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.5

To study the effects of foam core density and face-sheet thickness on the mechanical properties and failure modes of aluminum foam sandwich (AFS) beam, especially when the aluminum foam core is made in aluminum alloy and the face sheet thickness is less than 1.5 mm, three-point bending tests were investigated experimentally by using WDW-50E electronic universal tensile testing machine. Load.displacement curves were recorded to understand the mechanical response and photographs were taken to capture the deformation process of the composite structures. Results demonstrated that when foam core was combined with face-sheet thickness of 0.8 mm, its carrying capacity improved with the increase of core density. But when the thickness of face-sheet increased from 0.8 mm to 1.2 mm, result was opposite. For AFS with the same core density, their carrying capacity increased with the face-sheet thickness, but failure modes of thin face-sheet AFS were completely different from the thick face-sheet AFS. There were three failure modes in the present research: yield damage of both core and bottom face-sheet (Failure mode I), yield damage of foam core (Failure mode II), debonding between the adhesive interface (Failure mode III).

Effect of Homogenization Temperature on Microstructure and Mechanical Properties of Low-Carbon High-Boron Cast Steel

Fu Hanguang,Song Xuding,Lei Yongping,Jiang Zhiqiang,Xing Jiandong,Yang Jun,Wang Jinhua 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.3

The effects of quenching treatment on the microstructure, hardness, impact toughness, and wear resistance of low-carbon high-boron cast steel (LCHBS) containing 0.15-0.3 %C, 1.4-1.8 %B, 0.3-0.8 %Si, 0.8-1.2 %Mn, 0.5-0.8%Cr, 0.3-0.6%Ni, and 0.3-0.6%Mo have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and via an electron probe microanalyzer (EPMA), X-ray diffraction (XRD) analysis, impact tester, hardness tester, and wear tester. The as-cast matrix of LCHBS consists of pearlite and ferrite. There is 8-10 vol.% Fe2(B, C) type borocarbides in the matrix. The micro-hardness of Fe2(B, C) is 1430-1480 Hv. Fe2(B,C) shows no obvious change and the matrix completely transforms into lath martensite upon quenching at 900 °C to 1100 °C. The microhardness of the matrix and the macrohardness of the LCHBS sample show a slight increase with an increase of homogenization temperature. When the homogenization temperature exceeds 1050 °C, no distinct change in the hardness is observed. The change of homogenization temperature has no apparent effect on the impact toughness of LCHBS. The mass losses of LCHBS increase distinctly when the wear load increases. The homogenization temperature is less than 1000 °C and the wear rate of LCHBS decreases with an increase of temperature. The wear rate does not display any obvious change after exceeding a homogenization temperature of 1000 °C. The effects of quenching treatment on the microstructure, hardness, impact toughness, and wear resistance of low-carbon high-boron cast steel (LCHBS) containing 0.15-0.3 %C, 1.4-1.8 %B, 0.3-0.8 %Si, 0.8-1.2 %Mn, 0.5-0.8%Cr, 0.3-0.6%Ni, and 0.3-0.6%Mo have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and via an electron probe microanalyzer (EPMA), X-ray diffraction (XRD) analysis, impact tester, hardness tester, and wear tester. The as-cast matrix of LCHBS consists of pearlite and ferrite. There is 8-10 vol.% Fe2(B, C) type borocarbides in the matrix. The micro-hardness of Fe2(B, C) is 1430-1480 Hv. Fe2(B,C) shows no obvious change and the matrix completely transforms into lath martensite upon quenching at 900 °C to 1100 °C. The microhardness of the matrix and the macrohardness of the LCHBS sample show a slight increase with an increase of homogenization temperature. When the homogenization temperature exceeds 1050 °C, no distinct change in the hardness is observed. The change of homogenization temperature has no apparent effect on the impact toughness of LCHBS. The mass losses of LCHBS increase distinctly when the wear load increases. The homogenization temperature is less than 1000 °C and the wear rate of LCHBS decreases with an increase of temperature. The wear rate does not display any obvious change after exceeding a homogenization temperature of 1000 °C.

Fatigue behavior and damage mechanism of aluminum foam sandwich with carbonfiber face-sheets

Chang Yan,Jian Wang,Xuding Song 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.3

Aluminum foam sandwich (AFS) has been used in engineering field, where cyclic loading is in most of the applications. However, limited research has been done on the fatigue behavior of AFS. In the present study, fatigue performance of AFS made of aluminum foam core and carbon-fiber face-sheet was studied experimentally by a high frequency fatigue test machine and the damage mechanisms of the structure were studied by SEM. Results indicated that the fatigue life of AFS decreased with the increasing loading level. The S-N curve of AFS obeys three-parameter lognormal distribution in most of the cases. AFS was sensitive to cyclic loading level and the load capacity after cyclic loading improved significantly when the cyclic loading level was lower. The main life of AFS was its crack initiation stage. Three categories of damage mechanisms were observed. This study is of great significance to the design and application of AFS.

Experimental study on the fatigue performance of aluminum foam sandwich with 304 stainless steel face-sheet

Chang Yan,Chuanhe Jing,Xuding Song 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.3

This work focused on aluminum foam sandwich (AFS) with different foam core densities and different face-sheet thicknesses subjected to constant amplitude three-point bending cyclic loading to study its fatigue performance. The experiments were conducted out by a high frequency fatigue test machine named GPS-100. The experimental results showed that the fatigue life of AFS decreased with the increasing loading level and the structure was sensitive to cyclic loading, especially when the loading level was under 20%. S-N curves of nine groups of AFS specimens were obtained and the fatigue life of AFS followed three-parameter lognormal distribution well. AFS under low cyclic loading showed pronounced cyclic hardening and the static strength after fatigue test increased. For the same loading level, effects of foam core density and face-sheet thickness on the fatigue life of AFS structure were trade-off and for the same loading value, the fatigue life of AFS increased with aluminum foam core density or face-sheet thickness monotonously. Core shear was the main failure mode in the present study.

Effects of face-sheet materials on the flexural behavior of aluminum foam sandwich

Wei Xiao,Chang Yan,Weibo Tian,Weiping Tian,Xuding Song 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.3

Properties of AFS vary with the changes in the face-sheet materials. Hence, the performance of AFS can be optimized by selecting face-sheet materials. In this work, three types of face-sheet materials representing elastic-perfectly plastic, elastic-plastic strain hardening and purely elastic materials were employed to study their effects on the flexural behavior and failure mechanism of AFS systematically. Result showed face-sheet materials affected the failure mechanism and energy absorption ability of AFS significantly. When the foam cores were sandwiched by aluminum alloy 6061, the AFS failed by facesheet yielding and crack without collapse of the foam core, there was no clear plastic platform in the Load-Displacement curve. When the foam cores were sandwiched by stainless steel 304 and carbon fiber fabric, there were no face-sheet crack and the sandwich structure failed by core shear and collapse, plastic platform appeared. Energy absorption abilities of steel and carbon fiber reinforced AFS were much higher than aluminum alloy reinforced one. Carbon fiber was suggested as the best choice for AFS for its light weight and high performance. The versus strength ratio of face sheet to core was suggested to be a significant value for AFS structure design which may determine the failure mechanism of a certain AFS structure.