• 한국생산제조학회지
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• 제20권1호
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• pp.67-73
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• 2011

In this study, the manufacturing technology of a folding blind rivet was developed through finite element analysis(FEA). Numerical simulations of the folding blind rivet used to join two components have been performed with the finite element method for the forging process design. To minimize the process and manufacture the folding blind rivet without defects, a variety of design rules were proposed. From the results of FEA applied process design rules, an optimal six-stage process was proposed. The finite element simulation results such as shape of the forged rivet, strain distribution and forging load were investigated for the usefulness of the forging process of the blind rivet. In addition, the experiments have been implemented and their results were compared to the analytic results.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2577-2582
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• 2009

리벳은 두 부품을 결합하는 중요한 체결 요소이다. 본 연구에서는 부품의 진동 등에서도 잘 견디고 강한 체결력을 가지는 블라인드 리벳 몸체의 제작을 위해 강소성 유한요소해석을 사용하여 최적의 공정설계에 관한 연구를 수행하였다. 제안된 공정설계규칙 및 유한요소해석 결과를 토대로 4단계의 단조공정을 제시하였고, 폴딩 및 금형으로부터 이탈과 같은 결함을 예측하여 최적의 공정설계를 제안하였다. 또한, 소재의 유동 형상, 변형률 분포, 단조하중 등을 비교 검토하여 블라인드 리벳 몸체의 단조공정의 유용성을 확인하였다. 이들의 결과는 금형 설계 및 공정설계에 유용한 자료로 활용될 것이다.

• 소성∙가공
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• 제29권3호
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• pp.157-162
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• 2020

Blind rivet nuts are increasingly used in automotive for the joining of sheets. Their application, however, requires appropriate design guides to prevent catastrophic events arising from the failure of joints. In this study, the shaft shape of a frequently used M8 blind rivet nut is optimized based on 3D numerical analysis of the blind rivet nut considering the characteristics of thread. The thread needs to be modeled to suitably consider the fastening of the M8 bolt after the crimping process. FE analysis showed that while the friction in the contact between crimp flange and plate has no significant effect on the crimp geometry, shaft thickness (t) and shaft height (h) are the most significant design variables. The parameter study including various combinations of t and h reveals that they affect the gap (the distance between the crimped flange and the plate that develops through riveting) and the load acting on the plate. The gap is an indicator of the tightening force. It is found that t is inversely proportional to the gap, and proportional to the load, whereas h is proportional to the gap and inversely proportional to the load. Based on our FE analysis results, we propose the range 0.062 < t/h < 0.1 to ensure sufficient fastening (high clamping load, small gap) of the M8 blind rivet nut. The design guide for determining the t/h ratio proposed in this study can be used for general quantitative analysis of the size and the t/h ratio of blind rivet nuts.

• 소성∙가공
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• 제29권6호
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• pp.331-337
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• 2020

Blind rivet nuts (BRNs) are increasingly used in automotive industry because unlike conventional bolt fastening, BRN fastening requires access from one side only. Generally, fastening is conducted using automated units, but manual fastening may be resorted to in case of small quantities. Since the fastening direction is not exactly perpendicular to the sheet metal, the BRN axis is tilted with respect to the plate and may result in damage or incomplete fastening. As the tilt angle (clamping angle α) increases, undesired plate deformation occurs and the contact area of the plate with the BRN fastening area decreases, reducing the clamping effect. In this study, the reduction of the clamping effect with the α was investigated to ensure stable fastening force. M6 BRNs were used in the tests. The fastening force was measured as follows: the plate was cut in half through the center of the hole; the BRN was inserted into the hole and fastened; and the clamping angle a was measured (values, 0° ≤ α ≤ 9°). The force leading to the separation of the halves was measured using a universal testing machine (UTM). The maximum α range, in which the fastening force remains stable, was determined. Finite element (FE) analysis confirmed that the fastening force decreases approximately linearly with increasing α. Based on the experiment and FE analysis using various α, the fastening force was found to decrease with α. Further, the maximum tolerance for α that provides secure fastening without damage is suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.811-812
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• 2012