Effect of ultrasonically-assisted drilling on carbon-fibre-reinforced plastics

Makhdum, Farrukh; Phadnis, Vaibhav A.; Roy, Anish

doi:10.1016/j.jsv.2014.05.042

Cited by 108 publications

(54 citation statements)

References 34 publications

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“…This phenomenon is the so-called the Blaha effect. The same phenomena have been confirmed in many metals (e.g., [33][34][35]) and have been widely made to apply to the plastic working technique for industrial purpose such as wire drawing, deep drawing, rolling, and another metal forming techniques, since this phenomenon has an industrial significance (e.g., [36][37][38][39][40][41][42][43][44]). The Blaha effect has been explained by a temperature rise of materials [45], an abrupt increase in mobile dislocation density [46], a reduction in internal stress [47][48][49], or a stress superposition mechanism [50][51][52][53][54][55] so far.…”

Section: Introductionmentioning

confidence: 72%

Study on Dislocation-Dopant Ions Interaction in Ionic Crystals by the Strain-Rate Cycling Test during the Blaha Effect

Kohzuki

2018

Crystals

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Abstract:The interaction between a dislocation and impurities has been investigated by measurements of yield stress and proof stress, micro-hardness tests, direct observations of dislocation, internal friction measurements, or stress relaxation tests so far. A large number of investigations has been carried out by the separation of the flow stress into effective and internal stresses on the basis of the temperature dependence of yield stress, the strain rate dependence of flow stress, and stress relaxation. Nevertheless, it is difficult to investigate the interaction between a dislocation and obstacles during plastic deformation by the mentioned methods. As for the original method which combines strain-rate cycling tests with the Blaha effect measurement, the original method is different from above-mentioned ones and would be possible to clear it up. The strain-rate cycling test during the Blaha effect measurement has successively provided the information on the dislocation motion breaking away from the strain fields around dopant ions with the help of thermal activation, and seems to separate the contributions arising from the interaction between dislocation and the point defects and those from dislocations themselves during plastic deformation of ionic crystals. Such information on dislocation motion in bulk material cannot be obtained by the widely known methods so far. Furthermore, the various deformation characteristics derived from the original method are sensitive to a change in the state of dopant ions in a specimen by heat treatment, e.g., the Gibbs free energy (G 0 ) for overcoming of the strain field around the dopant by a dislocation at absolute zero becomes small for the annealed KCl:Sr 2+ single crystal (G 0 = 0.26 eV) in comparison with that for the quenched one (G 0 = 0.39 eV).

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Section: Introductionmentioning

confidence: 72%

Study on Dislocation-Dopant Ions Interaction in Ionic Crystals by the Strain-Rate Cycling Test during the Blaha Effect

Kohzuki

2018

Crystals

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“…15, have been studied to further elucidate the damage mechanisms within the large angle region of UD and MD [24][25][26][27][28][29][30][31][32][33][34][35][36][37] CFRPs. Fig.…”

Section: Temperature Effects On Hole Qualitiesmentioning

confidence: 99%

“…In comparison, infrared thermography is capable of acquiring complete temperature data within a large detection area, which enables offline data processing/analysis [19]. The reliability of such technology has been verified in several studies with simultaneous thermocouple measurements during the CFRP machining processes [31,36,37].…”

mentioning

confidence: 99%

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

Zhang

Wang

et al. 2018

International Journal of Machine Tools and Manufacture

124

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A B S T R A C TThis paper presents a comprehensive study on the complex drill-exit temperature characteristics in the drilling of unidirectional (UD) and multidirectional (MD) CFRPs using a state-of-art microscopy infrared imaging system. For the first time, temperature variation and distribution at drill exit have been revealed in full detail, associated with the CFRP material properties and drilling conditions. Results suggest that the actual drill/CFRP interactions have critical but similar effects on the drill-exit temperatures for UD and MD CFRPs. Specifically, three distinct cutting regions with varying temperature characteristics are evident when the main cutting edge is acting on the drill exit material. In all cases, the temperature distribution features elliptical shape, of which the eccentricity depends on the lay-up sequence and the drilling depth. In addition, the real-time temperature profiles and 2D/3D maximum temperature distribution maps are created with high visualization. With the aid of those findings, the relationships between drilling temperature maxima, their locations and drilling depths have been discovered and temperature effects on drill-exit damages have been elucidated for the first time. MD CFRP is proven more difficult to achieve high drilling qualities at certain fiber cutting angles than UD CFRP due to the associated temperature effects. Such important knowledge enables the identification of the heat affected zones and subsequently informs strategies for reducing the negative temperature effects.

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“…The utilisation of UAD in the drilling of CFRP has been shown to improve the quality of the holes, while the results for its application on titanium alloys are more varied, with some studies demonstrating different results for different alloys and others showing benefits with lower thrust forces. It is generally accepted that UAD increases tool life, which affects the quality of the holes, due to less titanium adhesion on the cutting edges and less edge chipping which corresponds to reduced titanium burr [36][37][38][39]. The process relies on the application of ultrasonic vibrations of 2-20 μm and 20-45 kHz amplitude and frequency, respectively, which is superimposed in the feed direction of the cutting edges during drilling.…”

Section: Examined Materialsmentioning

confidence: 99%

“…Nevertheless, higher cutting temperatures are observed during UAD of CFRPs and titanium alloys individually which are proportional to the ultrasonic amplitude due to energy consumption as the tool vibrates. Measurements of drilled through stacks of CFRP/Ti6Al4V, produced by UAD and CD with a three-point bore micrometre has shown more consistent and closer to nominal diameters for UAD [37][38][39][40]. The application of UAD demonstrates promising results and further investigation is required, while the combination of CFRPs and titanium alloys introduces unforeseen challenges that depend on the nature of the specific combination of CFRP and titanium alloy.…”

Section: Examined Materialsmentioning

confidence: 99%

A metrological inspection method using micro-CT for the analysis of drilled holes in CFRP and titanium stacks

Kourra

Warnett

Attridge

et al. 2016

Int J Adv Manuf Technol

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This paper demonstrates a novel method that combines X-ray computed tomography (CT) and image processing for investigating two materials with significantly different densities. CT is increasingly used in industrial applications of inspecting materials and defects. The limitations of the system and data reconstruction are continuously researched so as to improve the quality of the results. One of the most common issues in CT is beam hardening, frequently experienced in multi-material scanning. The materials examined to demonstrate the method are carbon fibre reinforced polymers (CFRP) and titanium alloy Ti6Al4V, often used in combination in industry to optimise the weight to strength ratio. The assembly of the materials is usually achieved by bolting and riveting, which requires drilling through the two materials together. The machining of these materials is difficult due to their higher specific properties and as a result tool wear is always an issue. CFRPs properties depend on the nature, orientation and bond of the fibres and as a result drilling affects their service life. The results of the method ensure the quality of the drilled holes by measuring the variation of the maximum diameter, circularity, positioning of the hole and an examining the entrance delamination and exit burrs by image processing.

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Effect of ultrasonically-assisted drilling on carbon-fibre-reinforced plastics

Cited by 108 publications

References 34 publications

Study on Dislocation-Dopant Ions Interaction in Ionic Crystals by the Strain-Rate Cycling Test during the Blaha Effect

Study on Dislocation-Dopant Ions Interaction in Ionic Crystals by the Strain-Rate Cycling Test during the Blaha Effect

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

A metrological inspection method using micro-CT for the analysis of drilled holes in CFRP and titanium stacks

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