scholarly journals Direct Fiber Simulation of a Compression Molded Ribbed Structure Made of a Sheet Molding Compound with Randomly Oriented Carbon/Epoxy Prepreg Strands—A Comparison of Predicted Fiber Orientations with Computed Tomography Analyses

2020 ◽  
Vol 4 (4) ◽  
pp. 164
Author(s):  
Jan Teuwsen ◽  
Stephan K. Hohn ◽  
Tim A. Osswald
Keyword(s):  
Computed Tomography ◽  
Detailed Comparison ◽  
Micro Computed Tomography ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Discontinuous Fiber ◽  
Orientation Tensors ◽  
Fiber Sheet ◽  
Local Fiber ◽  
Good Agreement

Discontinuous fiber composites (DFC) such as carbon fiber sheet molding compounds (CF-SMC) are increasingly used in the automotive industry for manufacturing lightweight parts. Due to the flow conditions during compression molding of complex geometries, a locally varying fiber orientation evolves. Knowing these process-induced fiber orientations is key to a proper part design since the mechanical properties of the final part highly depend on its local microstructure. Local fiber orientations can be measured and analyzed by means of micro-computed tomography (µCT) and digital image processing, or predicted by process simulation. This paper presents a detailed comparison of numerical and experimental analyses of compression molded ribbed hat profile parts made of CF-SMC with 50 mm long randomly oriented strands (ROS) of chopped unidirectional (UD) carbon/epoxy prepreg tape. X-ray µCT scans of three entire CF-SMC parts are analyzed to compare determined orientation tensors with those coming from a direct fiber simulation (DFS) tool featuring a novel strand generation approach, realistically mimicking the initial ROS charge mesostructure. The DFS results show an overall good agreement of predicted local fiber orientations with µCT measurements, and are therefore precious information that can be used in subsequent integrative simulations to determine the part’s mesostructure-related anisotropic behavior under mechanical loads.

Region-of-Interest X-Ray Tomography for the Non-Destructive Characterization of Local Fiber Orientation in Large Fiber Composite Parts

2019 ◽  
Vol 809 ◽  
pp. 587-593
Author(s):  
Simon Zabler ◽  
Katja Schladitz ◽  
Kilian Dremel ◽  
Jonas Graetz ◽  
Dascha Dobrovolskij
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Fiber Orientation ◽  
Fiber Composite ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Anisotropic Thermal Conductivity ◽  
Local Fiber

To detect and characterize materials defects in fiber composites as well as for evaluatingthe three-dimensional local fiber orientation in the latter, X-ray micro-CT is the preferred methodof choice. When micro computed tomography is applied to inspect large components, the method isreferred to as region-of-interest computed tomography. Parts can be as large as 10 cm wide and 1 mlong, while the measurement volume of micro computed tomography is a cylinder of only 4 − 5 mmdiameter (typical wall thickness of fiber composite parts). In this report, the potentials and limits ofregion-of-interest computed tomography are discussed with regard to spatial resolution and precisionwhen evaluating defects and local fiber orientation in squeeze cast components. The micro computedtomography scanner metRIC at Fraunhofer‘s Development Center X-ray Technology EZRT deliversregion-of-interest computed tomography up to a spatial resolution of 2 μm/voxel, which is sufficientfor determining the orientation of natural or synthetic fibers, wood, carbon and glass. The mean localfiber orientation is estimated on an isotropic structuring element of approximately 0.1 mm length bymeans of volume image analysis (MAVI software package by Fraunhofer ITWM). Knowing the exactlocal fiber orientation is critical for estimating anisotropic thermal conductivity and materials strength.

Micro-Computed Tomography Image Based Numerical Elastic Homogenization of MMCs

2014 ◽  
Vol 627 ◽  
pp. 437-440 ◽  
Author(s):  
Yuriy Sinchuk ◽  
Stefan Dietrich ◽  
Matthias Merzkirch ◽  
Kay André Weidenmann ◽  
Romana Piat
Keyword(s):  
Computed Tomography ◽  
Elastic Properties ◽  
Ceramic Composite ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Tomography Image ◽  
Metal Ceramic ◽  
Computed Tomography Image ◽  
2D And 3D ◽  
Good Agreement

Properties of an interpenetrating metal–ceramic composite with freeze-cast preforms are investigated. For the estimation of elastic properties of the composite numerical homogenization approaches for 2D and 3D finite element models are implemented. The FE models are created based on micro-computed tomography (μCT) images. The results of the numerical 2D and 3D modeling coincide and are in good agreement with available experimental measurements of elastic properties.

scholarly journals CHARACTERIZATION OF THE FRACTURE MECHANICAL BEHAVIOR OF C-SMC MATERIALS

2018 ◽  
Vol 18 ◽  
pp. 1 ◽  
Author(s):  
Martin Tiefenthaler ◽  
Philipp S. Stelzer ◽  
Chi N. Chung ◽  
Volker Reisecker ◽  
Zoltan Major
Keyword(s):  
Carbon Fiber ◽  
Tensile Tests ◽  
Representative Specimen ◽  
Carbon Fiber Composites ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Compound C ◽  
Specimen Width ◽  
Fiber Sheet ◽  
Point Bend

The fracture mechanics of random discontinuous Carbon Fiber Sheet Molding Compound (C-SMC) materials compared to traditional carbon fiber composites are not well understood. An experimental study was carried out to characterize the fracture behavior of such C-SMC materials. Mode I tests, using double cantilever beam specimens, and mode II tests, adopting the four-point bend, end-notched flexure configuration, were performed. Results show high variations in the forcedeflection responses and scatter in the fracture toughness properties GIc and GIIc, due to the complex mesostructure defined by random oriented carbon fiber chips. To investigate the influence of the mesostructure, tensile tests with varying specimen width and thickness were assessed by stochastic measures to find the representative specimen size.

Fiber bundle tracking method to analyze sheet molding compound microstructure based on computed tomography images

2021 ◽  
Vol 117 ◽  
pp. 102370
Author(s):  
Ludwig Schöttl ◽  
Kay André Weidenmann ◽  
Trevor Sabiston ◽  
Kaan Inal ◽  
Peter Elsner
Keyword(s):  
Computed Tomography ◽  
Fiber Bundle ◽  
Molding Compound ◽  
Tracking Method ◽  
Sheet Molding Compound ◽  
Computed Tomography Images
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