Influence of machining damage generated during trimming of CFRP composite on the compressive strength

Nguyen-Dinh, Ngoc; Zitoune, Rédouane

doi:10.1177/0021998319883335

Cited by 24 publications

(15 citation statements)

References 33 publications

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“…This is vitally important as the defect type and size have been directly linked to mechanical performance. 9,[23][24][25][26] By using the EF method, a novel metric which accounts for machining induced damage of CFRP edge trimming has been generated. The novel metric is able to provide a value for total damage area compared to a theoretically straight cut.…”

Section: Discussionmentioning

confidence: 99%

Epifluorescent microscopy of edge-trimmed carbon fibre-reinforced polymers: An alternative to computed tomography scanning

Ashworth

Fairclough

Monoranu

et al. 2020

Advanced Composites Letters

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X-Ray computed tomography (XCT) can be used to detect edge-milled carbon fibre-reinforced polymer (CFRP) defects. Significantly this method is able to show subsurface defects that cannot be captured by traditional methods such as stylus-based or more novel areal methods of surface quality measurement. While useful, this method can be prohibitive due to high equipment cost, scanning time and image resolution. XCT can often produce artefacts which falsely predict damage or obscure damage and depending on machine X-ray power often cannot resolve damage to fibre diameter which is critical when observing milled quality of the surface/subsurface. This study utilises epifluorescent (EF) optical microscopy to provide high-quality optical images as an alternative to XCT to observe through-depth damage of CFRP materials. The method of computing the novel damage criteria is presented, as well as the validation of the method which compares EF to XCT. Subsurface damage of fabric and unidirectional (UD) materials in 0°, 45°, 90° and −45° orientations to the cutting edge is observed to demonstrate typical defects. A novel metric resulting from the EF method provides a total area of damage when compared to a theoretically straight cut across the face of the edge-milled CFRP. The method shows that different subsurface damage exists for different fibre orientations to the cutting edge, highlighting the clear need for through-depth analysis of machined edges. In addition, the method is shown to be a suitable alternative to XCT with scope for further development of industrial aerospace and automotive quality control of machined CFRP parts.

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Section: Discussionmentioning

confidence: 99%

Epifluorescent microscopy of edge-trimmed carbon fibre-reinforced polymers: An alternative to computed tomography scanning

Ashworth

Fairclough

Monoranu

et al. 2020

Advanced Composites Letters

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“…6,8,20 A machined multidirectional composite surface has been shown to have a non-homogeneous surface: this has been shown in the literature using various methods, including computed tomography (CT), scanning electron microscopy (SEM) and optical focus variation measurement techniques. 11,12,16,21 Other researchers have used advanced techniques to assess sub surface damage including terahertz imaging and epiflourescent microscopy. 22,23 Wang et al 24 have used a new image subtraction method to quantify the extent of delaminated fibres on an edge trimmed edge using an image subtraction method.…”

Section: Review Of State-of-the-art Measurement Methods and Statisticmentioning

confidence: 99%

“…1 Previous studies have indicated that surface defects and machining induced surface roughness can affect the mechanical performance of composite material. [12][13][14] It has been shown by Haddad et al, 15 that the cutting speed will have a significant effect on surface roughness. Further research indicates that surface roughness will play a role in reducing inter-laminar shear strength in IMS/977-2 composite samples.…”

Section: Introductionmentioning

confidence: 99%

Towards intelligent CFRP composite machining: Surface analysis methods and statistical data analysis of machined fibre laminate surfaces

Duboust

Watson

Marshall

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part B:

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Many carbon fibre reinforced polymer composite parts need to be edged trimmed before use to ensure both geometry and mechanical performance of the part edge matches the design intent. Measurement and control of machining induced surface damage of composite material is key to ensuring the part retains its strength and fatigue properties. Typically, the overall surface roughness of the machined face is taken to be an indicator of the amount of damage to the surface, and it is important that the measurement and prediction of surface roughness is completed reliably. It is known that the surface damage is heavily dependent on the fibre orientation of the composite and cutting tool edge condition. This research has developed a new ply-by-ply surface roughness measurement methods using optical focus variation surface analysis and image segmentation for calculating areal surface roughness parameters of a machined carbon fibre composite laminate. Machining experiments have been completed using a polycrystalline diamond edge trimming tool at increasing levels of cutting edge radius. Optical surface measurement and µ-CT scanning have been used to assess machining induced surface and sub-surface defects on individual fibre orientations. Statistical analysis has been used to assess the significance of machining parameters on Sa (arithmetic mean height of area) and Sv (areal magnitude of maximum valley depth) areal roughness parameters, on both overall roughness and ply-by-ply fibre orientations. Empirical models have been developed to predict surface roughness parameters using statistical methods. It has been shown that cutting edge degradation, fibre orientation and feed rate will significantly affect the cutting mechanism, machining induced surface defects and surface roughness parameters.

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“…In the literature, the most studied factors to evaluate delamination produced after milling are cutting parameters, fiber orientation angle and cutting tool characteristics (material, teeth number, etc.) [ 4 , 5 , 6 , 7 , 8 ]. Cutting speed and feed are mainly studied [ 9 , 10 , 11 , 12 ], but only a few authors also include depth of cut [ 13 ] since most of them think that its influence on delamination is not as relevant as cutting speed and feed.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Different Parameters to Evaluate Delamination in Edge Trimming of Basalt Fiber Reinforced Plastics (BFRP)

et al. 2020

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Delamination is one of the main problems that occur when machining fiber-reinforced composite materials. In this work, Types I and II of delamination are studied separately in edge trimming of basalt fiber reinforced plastic (BFRP). For this purpose, one-dimensional and area delamination parameters are defined. One-dimensional parameters (Wa and Wb) allow to know average fibers length while the analysis of area delamination parameters (Sd) allow to evaluate delamination density. To study delamination, different tests are carried out modifying cutting parameters (cutting speed, feed per tooth and depth of cut) and material characteristics (fiber volume fraction and fiber orientation). Laminates with a lower fiber volume fraction do not present delamination. Attending to one-dimensional parameters it can be concluded that Type II delamination is more important than Type I and that a high depth of cut generates higher values of delamination parameters. An analysis of variance (ANOVA) is performed to study area parameters. Although delamination has a random nature, for each depth of cut, more influence variables in area delamination are firstly, feed per tooth and secondly, cutting speed.

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Influence of machining damage generated during trimming of CFRP composite on the compressive strength

Cited by 24 publications

References 33 publications

Epifluorescent microscopy of edge-trimmed carbon fibre-reinforced polymers: An alternative to computed tomography scanning

Epifluorescent microscopy of edge-trimmed carbon fibre-reinforced polymers: An alternative to computed tomography scanning

Towards intelligent CFRP composite machining: Surface analysis methods and statistical data analysis of machined fibre laminate surfaces

Comparison of Different Parameters to Evaluate Delamination in Edge Trimming of Basalt Fiber Reinforced Plastics (BFRP)

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