X-ray micro-computed tomography analysis of impact damage morphology in composite sandwich structures due to cold temperature arctic condition

2018 ◽  
Vol 52 (25) ◽  
pp. 3509-3522 ◽  
Author(s):  
MH Khan ◽  
Mohammed Elamin ◽  
Bing Li ◽  
KT Tan
Keyword(s):  
Computed Tomography ◽  
Low Temperature ◽  
Impact Damage ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Foam Core ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Reinforced Polymer ◽  
The Impact

In this study, X-ray micro-computed tomography is employed to characterize the impact damage mechanisms in foam core sandwiched composites, paying particular attention to the influence of extreme low temperature effects. Investigation on impact response reveals that more energy absorption with lower impact damage force occurs at lower temperature. Results evidently show that test temperature has a significant influence on the impact damage behavior. Post-mortem inspection portrays clear relationships between damages in both foam core and carbon fiber reinforced polymer facesheets, as well as exposed test temperature. Specimens impacted at extreme low temperature (−70℃) exhibit less strength, and higher susceptibility to damage, verified by severer penetration of the impactor. Micro-computed tomography is exploited to examine cross-sectional views of the impacted specimens, showing detailed damage mechanisms of the carbon fiber-reinforced polymer facesheets and the foam core, thereby evidently revealing multiple complex impact damage modes such as fiber breakage, delamination, core shearing and crushing, facesheet-core debonding, which are all strongly influenced by arctic low temperature. The findings of this work will lead to improved design for advanced composite structures with enhanced impact resistance and damage tolerance in extreme cold environment particularly in the arctic region.

scholarly journals Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates

2020 ◽  
Vol 54 (27) ◽  
pp. 4325-4337 ◽  
Author(s):  
Janez Rus ◽  
Alex Gustschin ◽  
Hubert Mooshofer ◽  
Jan-Carl Grager ◽  
Klaas Bente ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Dark Field ◽  
Piezoelectric Transducers ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
X Ray ◽  
Reinforced Polymer ◽  
Non Destructive ◽  
Ultrasound Testing ◽  
Destructive Methods

In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultrasound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoacoustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.

scholarly journals Quantifying the impact of soil compaction on root system architecture in tomato (Solanum lycopersicum) by X-ray micro-computed tomography

2012 ◽  
Vol 110 (2) ◽  
pp. 511-519 ◽  
Author(s):  
Saoirse R. Tracy ◽  
Colin R. Black ◽  
Jeremy A. Roberts ◽  
Craig Sturrock ◽  
Stefan Mairhofer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Root System ◽  
Solanum Lycopersicum ◽  
System Architecture ◽  
Soil Compaction ◽  
Root System Architecture ◽  
Micro Computed Tomography ◽  
X Ray ◽  
The Impact

scholarly journals Effect of freezing on the microstructure of a highly decomposed peat material close to water saturation when used prior to X-ray micro computed tomography

2021 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Olivier Rozembaum ◽  
Emmanuel Le Trong
Keyword(s):  
Computed Tomography ◽  
Pore Volume ◽  
Specific Volume ◽  
Water Saturation ◽  
Organic Matrix ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Two Samples ◽  
Before And After ◽  
The Impact

Abstract. The modelling of peatland functioning, in particular the impact of anthropogenic warming and direct human disturbance on CO2, CH4 and N2O, requires detailed knowledge of the peat structure and of both water and gas flow with respect to the groundwater table level. To this end, freezing is nowadays increasingly used to obtain small size peat samples for X-ray micro computed tomography (X-ray μ-CT) as required by the need to increase the resolution of the 3D X-ray CT images of the peat structure recorded. The aim of this study was to analyze the structure of a peat material before and after freezing using X-ray μ-CT and to look for possible alterations in the structure by investigating looking at the air-filled porosity. A highly decomposed peat material close to water saturation was selected for study and collected between 25 and 40 cm depth. Two samples 4 × 4 × 7 cm3 in volume were analyzed before and after freezing using an X-ray μ-CT Nanotom 180NF (GE Phoenix X-ray, Wunstorf, Germany) with a 180 kV nanofocus X-ray tube and a digital detector array (2304 × 1152 pixels Hamamatsu detector). Results showed that the continuity and cross section of the air-filled tubular pores several hundreds to about one thousand micrometers in diameter were altered after freezing. Many much smaller air-filled pores not detected before freezing were also recorded after freezing with 470 and 474 pores higher than one voxel in volume (60 × 60 × 60 μm3 in volume each) before freezing, and 4792 and 4371 air-filled pores higher than one voxel in volume after freezing for the two samples studied. Detailed analysis showed that this increase resulted from a difference in the whole range of pore size studied and particularly from a dramatic increase in the number of air-filled pores ranging between 1 voxel (216 103 μm3) and 50 voxels (10.8 106 μm3) in volume. Theoretical calculation of the consequences of the increase in the specific volume of water by 8.7 % when it turns from liquid to solid because of freezing led to the creation of a pore volume in the organic matrix which remains saturated by water when returning to room temperature and consequently to the desaturation of the largest pores of the organic matrix as well as the finest tubular pores which were water-filled before freezing. These new air-filled pores are those measured after freezing using X-ray μ-CT and their volume is consistent with the one calculated theoretically. They correspond to small air-filled ovoid pores several voxels in volume to several dozen voxels in volume and to discontinuous air-filled fine tubular pores which were both detected after freezing. Finally, the increase in the specific volume of water because of freezing appears also be also responsible for the alteration of the already air-filled tubular pores before freezing as shown by the 3D binary images and the pore volume distribution.

scholarly journals Investigation of the Internal Structure of Fiber Reinforced Geopolymer Composite under Mechanical Impact: A Micro Computed Tomography (µCT) Study

2019 ◽  
Vol 9 (3) ◽  
pp. 516 ◽  
Author(s):  
Sneha Samal ◽  
Marcela Kolinova ◽  
Hubert Rahier ◽  
Giovanni Dal Poggetto ◽  
Ignazio Blanco
Keyword(s):  
Computed Tomography ◽  
Internal Structure ◽  
Impact Damage ◽  
Three Dimensional ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Micro Computed Tomography ◽  
Mechanical Impact ◽  
The Impact ◽  
Geopolymer Composites

The internal structure of fiber reinforced geopolymer composite was investigated by microfocus X-ray computed tomography (µCT) under mechanical impact. µCT is a non-destructive, multi approach technique for assessing the internal structures of the impacted composites without compromising their integrity. The three dimensional (3D) representation was used to assess the impact damage of geopolymer composites reinforced with carbon, E-glass, and basalt fibers. The 3D representations of the damaged area with the visualization of the fiber rupture slices are presented in this article. The fiber pulls out, and rupture and matrix damage, which could clearly be observed, was studied on the impacted composites by examining slices of the damaged area from the center of the damage towards the edge of the composite. Quantitative analysis of the damaged area revealed that carbon fabric reinforced composites were much less affected by the impact than the E-glass and basalt reinforced composites. The penetration was clearly observed for the basalt based composites, confirming µCT as a useful technique for examining the different failure mechanisms for geopolymer composites. The durability of the carbon fiber reinforced composite showed better residual strength in comparison with the E-glass fiber one.

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