Computational micromechanics model based failure criteria for chopped carbon fiber sheet molding compound composites

2020 ◽  
Vol 200 ◽  
pp. 108400 ◽  
Author(s):  
Haibin Tang ◽  
Zhangxing Chen ◽  
Hongyi Xu ◽  
Zhao Liu ◽  
Qingping Sun ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Failure Criteria ◽  
Molding Compound ◽  
Micromechanics Model ◽  
Sheet Molding Compound ◽  
Model Based ◽  
Fiber Sheet ◽  
Computational Micromechanics ◽  
Carbon Fiber Sheet

scholarly journals Experimental Investigation on the In-Plane Creep Behavior of a Carbon-Fiber Sheet Molding Compound at Elevated Temperature at Different Stress States

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2545
Author(s):  
David Finck ◽  
Christian Seidel ◽  
Anika Ostermeier ◽  
Joachim Hausmann ◽  
Thomas Rief
Keyword(s):  
Elevated Temperature ◽  
Carbon Fiber ◽  
Creep Strain ◽  
Strain Rates ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Tension And Compression ◽  
Fiber Sheet ◽  
Stress States ◽  
Carbon Fiber Sheet

The creepage behavior of one thermosetting carbon fiber sheet molding compound (SMC) material was studied applying in-plane loading at 120 °C. Loads were applied in bending, tension and compression test setups at the same in-plane stress level of 47 MPa. Different creep strain rates were determined. The creep strain rate in flexural loading was significantly higher than in tensile loading. The test specimens in compression loading collapsed within minutes and no findings regarding the creep strain rates were possible. Overall, it was observed that the thermosetting press resin of this industrially used material had only little creep load bearing capacity at the mentioned temperature when loaded in mixed stress states. The test data has high usage for estimating design limits of structural loaded SMC components at elevated temperature.

scholarly journals Mechanical characterization of anisotropy on a carbon fiber sheet molding compound composite under quasi-static and fatigue loading

2018 ◽  
Vol 53 (11) ◽  
pp. 1437-1457 ◽  
Author(s):  
C Nony-Davadie ◽  
L Peltier ◽  
Y Chemisky ◽  
B Surowiec ◽  
F Meraghni
Keyword(s):  
Carbon Fiber ◽  
Flow Direction ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Compression Process ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Stiffness Reduction ◽  
Fiber Sheet ◽  
Carbon Fiber Sheet

The paper presents an experimental analysis of the anisotropic effects of the structural advanced carbon fiber sheet molding compound composites (AC-SMCs) subjected to quasi-static and fatigue loading. Two configurations of AC-SMC composites (randomly oriented and highly oriented) considering three different orientations (0°, 45°, 90°) with respect to the material thermo-compression flow direction are investigated under quasi-static and fatigue tensile loading. The effects of fibers orientation induced by the thermo-compression process are analyzed in terms of ultimate strength, elastic modulus, and macroscopic damage corresponding to the stiffness reduction, and related to the quasi-static and fatigue behavior. For both loading conditions, the macroscopic damage of AC-SMC randomly oriented exhibits a two-stage evolution without any damage saturation prior to the samples' failure. In addition, the difference between the highly oriented and randomly oriented configurations is pronounced especially for the 45° and 90° orientations. Post-mortem X-ray radiography and SEM observations show that damage mechanisms such as microcracks appear between and inside bundles, and their occurrence depends on the sample orientation. Experimental findings are compared with those of an equivalent advanced glass fiber reinforced sheet molding compounds composite. The degree of anisotropy is more pronounced for AC-SMC. Indeed, the dependency of the behavior during the manufacturing process induces orientation. Furthermore, the damage evolutions of the two types of SMCs have displayed different kinetics, especially for the saturation stage which is not observed for the AC-SMC composite.

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.

scholarly journals Creep-Induced Screw Preload Loss of Carbon-Fiber Sheet Molding Compound at Elevated Temperature

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3598 ◽  
Author(s):  
Finck ◽  
Seidel ◽  
Hausmann ◽  
Rief
Keyword(s):  
Carbon Fiber ◽  
Testing Machine ◽  
Fiber Reinforced Polymers ◽  
Element Analysis ◽  
Reinforced Polymers ◽  
Molding Compound ◽  
Test Setup ◽  
Sheet Molding Compound ◽  
Fiber Sheet ◽  
Optical Strain

The application of chopped-fiber reinforced polymers in screwed connections at high temperatures raises the question of creep under long-term loading. While up to now thermoplastic materials have mainly been the focus of attention when it comes to creep, this paper shows that thermoset carbon-fiber SMCs (sheet mold compounds) can also be affected by this phenomenon. Screwed connections were investigated regarding their loss of preload force at 120 °C ambient temperature. Additionally, strain–time diagrams were recorded at different stress levels at 120 °C in a creep test setup of a universal testing machine by using optical strain tracking of SMC coupons. The transverse modulus under compression in thickness direction was determined in the same test setup. For data application within a FEA (finite element analysis) software power law curves according to Norton–Bailey creep law were fitted in the strain–time graphs. The applicability of the obtained creep law was crosschecked with a test carried out on the loss of preload force of a screwed connection. The developed simulative methodology offers the possibility to simulate various mounting situations of the bolted connection and to investigate measures against the loss of preload force easily. A promising possibility to limit the loss of preload force due to creep was simulatively evaluated.

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