Effect of workpiece stiffness on thrust force and delamination in drilling thin composite laminates

Luo, Bin; Yuan, Li; Zhang, Kaifu; Cheng, Hui; Liu, Shunuan

doi:10.1177/0021998315580449

Cited by 12 publications

(3 citation statements)

References 25 publications

(33 reference statements)

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“…Though initial stress or damage might cause slight delamination during drilling and bolt installation as analyzed in literatures, 19,32 such riveting-induced damage is considered as neglectable here for the joints with clearance-fit and thick enough laminates.…”

Section: Modelingmentioning

confidence: 99%

Damage mode and load distribution of countersunk bolted composite joints

Cheng

Huang³

et al. 2020

Journal of Composite Materials

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Tensile experiments were conducted with single-bolted and multi-bolted countersunk composite-metal joints. The finite element models with Hashin criteria and modified Camanho degradation law were developed to predict the bearing load and to simulate the failure behavior. The models were validated with the experimental results, including load-displacement curves and composite damage profiles. Based on the verified models, bolt load distributions of multi-bolted joints were calculated and analyzed before and after damage occurs. Results show that composite damages can change the bolt load distributions to a certain extent, which needs to be considered during the structure design. To adjust the bolt load distribution, the effects of joint variables, including bolt-hole clearance, bolt spacing, countersunk height ratio, and bolt stiffness combination, have been studied. It is found that the increase of the pin clearance around the largest bearing bolt would decrease its corresponding bearing load. The countersunk height ratio affects the bolt load distribution difference that a greater ratio leads to a less difference. The bolt spacing and bolt stiffness can also be used to reduce the bolt load distribution difference with elaborately designed combinations.

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Section: Modelingmentioning

confidence: 99%

Damage mode and load distribution of countersunk bolted composite joints

Cheng

Huang³

et al. 2020

Journal of Composite Materials

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“…Delamination damage is a force-associated failure that can be classified into two types [14], namely peel-up delamination and push-out delamination [1]. Peel-up delamination is caused by tool geometry [15], whereas push-out delamination is caused by thrust force inserted by the drill point [16]. Because of the irreparable nature of delamination damage, the composite laminate has to be rejected when delamination reaches a certain extent [17].…”

Section: Introductionmentioning

confidence: 99%

Hole Quality Observation in Single-Shot Drilling of CFRP/Al7075-T6 Composite Metal Stacks Using Customized Twist Drill Design

Mathavan

Hassan

et al. 2022

J. Compos. Sci.

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In the modern aircraft manufacturing industry, the use of fiber metal stack-up material plays an important role. During assembly, these stack-up materials need to be drilled, and single-shot drilling is the best option to avoid misalignments. This paper discusses hole quality in terms of hole edge defects and hole integrity with respect to tool geometry. In this study, tungsten carbide (WC) twist-type drills with various geometric features were fabricated, tested, and evaluated. Twenty custom twist drill bits with primary clearance angles ranging from 6° to 8°, chisel edge angles from 30° to 45°, and point angles from 130° to 140° were fabricated. The CFRP and Al 7075-T6 were stacked up, and a feed rate of 0.05 mm/rev and spindle speed of 2600 rev/min were used for all drilling experiments. The experimental array was constructed using response surface methodology (RSM) to design the experiments. The impact of factors and their importance on hole quality were investigated using analysis of variance (ANOVA). The study demonstrates that the primary clearance angle, followed by the chisel edge angle, is the most important factor determining hole quality. As a function of tool geometry, correlation models between exit delamination and burr height were developed. The findings suggested that, within the range of parameters examined, the proposed correlation models might be utilized to predict performance measures. For drilling CFRP/AL7075-T6 stack material in a single shot, the ideal twist drill geometry was determined to be a 45° chisel edge angle, 8° primary clearance angle, and 130° point angle. For optimum drill geometry, the discrepancy between the expected and actual experiment values was 0.11% for exit delamination and 9.72% for burr height. The findings of this research elucidate the relationship between tool geometry and hole quality in single-shot drilling of composite-metal stacks, and more specifically, they may serve as a useful, practical guide for single-shot drilling of CFRP/Al7075-T6 stack for the manufacture of aircraft.

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“…10 Investigation of delamination is mostly performed using drilling process. 11,12 Davim et al 13 presented an experimental study of drilling GFRPs. Analysis of variance (ANOVA) was carried out to investigate the delamination damage in terms of cutting parameters.…”

Section: Introductionmentioning

confidence: 99%

Environmental, mechanical and materialistic effects on delamination damage of glass fiber composites: Analysis and optimization

Tabatabaeian

Baraheni

Amini

et al. 2019

Journal of Composite Materials

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Machining process of glass fiber composites usually induces delamination damage. The presence of delamination may cause changes in the mechanical characteristics of the composite structures. In this research, a comprehensive experimental study is performed to analyze the influence of different parameters such as thermal fatigue, lay-up arrangement, resin type, feed rate and cutting velocity on the delamination of glass fiber composites under different drilling processes. Besides, influence of ultrasonic vibration exerting on the tool as a new and high-tech process is investigated. To follow this aim, different composite specimens with various resin types and lay-up arrangements are fabricated and a thermal fatigue condition is provided. Additionally, the Taguchi method is employed to obtain the optimized damage reduction condition in terms of mentioned parameters. The results indicated that thermal fatigue and unsymmetrical lay-up arrangement result in more delamination damage. It was also established that the influence of mentioned parameters is more considerable in higher cutting velocities. Moreover, ultrasonic vibration application is suggested to have the least delamination damage.

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Effect of workpiece stiffness on thrust force and delamination in drilling thin composite laminates

Cited by 12 publications

References 25 publications

Damage mode and load distribution of countersunk bolted composite joints

Damage mode and load distribution of countersunk bolted composite joints

Hole Quality Observation in Single-Shot Drilling of CFRP/Al7075-T6 Composite Metal Stacks Using Customized Twist Drill Design

Environmental, mechanical and materialistic effects on delamination damage of glass fiber composites: Analysis and optimization

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