A simplified method of evaluating ratcheting in bellows and a test of its validation

Yamashita, Takuya; Tsukimori, Kazuyuki; Nakamura, M.; Iwata, K.; Imazu, Akira

doi:10.1016/0308-0161(90)90027-f

Cited by 12 publications

(3 citation statements)

References 3 publications

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“…The ratcheting behavior of PTFE has been drawn more attention in recent years due to the application of PTFE material subjected to a cyclic loading in engineering practice. In the last two decades, the ratcheting behaviors of metals and alloys have been carried out by experiments and simulations . Simultaneously, the ratcheting experiments were also conducted for metal matrix composites, polymers, and polymer matrix composites .…”

Section: Introductionmentioning

confidence: 99%

Uniaxial time‐dependent ratcheting behavior of bronze powder filled polytetrafluoroethylene at room and high temperature

Gao

et al. 2013

Polymer Engineering & Sci

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A series of tensile and ratcheting experiments for cold compaction polytetrafluoroethylene (PTFE) and bronze filled PTFE (PTFE/bronze) were conducted with Dynamic Mechanical Analyzer (DMA‐Q800) at room and high temperature (473 K). The effects of peak stress‐holding time, creep, recovery, mean stress history, stress‐rate history, and pretension on the ratcheting behavior of PTFE/bronze were investigated. It is found that longer peak stress‐holding time leads to larger ratcheting strain accumulation. In the meantime, the ratcheting strain accumulates more rapidly at high temperature and the influence of temperature is more obvious than that of the additive fraction of bronze. Creep strain produced during the uploading and the stress‐holding time only partially recovers in the unloading process. Moreover, prior lower stress rate enhances the deformation resistance and restrains the ratcheting of subsequent cycling at higher stress rate. The ratcheting strain in the subsequent cyclic loading at lower mean stress is also restrained by previous cyclic loading at higher mean stress. Finally, the elastic modulus increases and the ratcheting strain is restrained apparently after the pretension. In addition, the elastic modulus and ratcheting strain of the PTFE/bronze with both pretension and recovery are smaller than those with pretension but without recovery. POLYM. ENG. SCI., 54:1571–1578, 2014. © 2013 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Uniaxial time‐dependent ratcheting behavior of bronze powder filled polytetrafluoroethylene at room and high temperature

Gao

et al. 2013

Polymer Engineering & Sci

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“…Paying attention to this analogy, authors arranged seismic ratcheting occurrence conditions in the same way as the Bree diagram. Yamashita et al developed a theoretical ratchet diagram for rectangular beams subjected to the primary bending load with secondary bending load (Yamashita T, et al, 1990).…”

Section: Introduction To Ratchetingmentioning

confidence: 99%

Study on ratcheting of beams under the combination of gravity and seismic load

Lyu

Ichimiya

Bari

et al. 2020

Mechanical Engineering Journal

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Ratcheting is one common phenomenon under excessive earthquakes. This study focuses on clarifying the ratcheting mechanism of beams subjected to the combination of gravity and seismic loadings. The sinusoidal excitations or their combinations represented the seismic loadings. Gravity acted as load-controlled loading and was applied by the self-weight of the beam as well as the additional mass put at the free end of the beam. A cyclic acceleration was applied at the base of the beam to provide the source of dynamic loading assumed as seismic loading. Equivalent loading conditions were put in experiments as in numerical analysis to validate the nonlinear finite element analyses. The analogy between thermal ratcheting and vibration ratcheting was considered to investigate the characteristics of cyclic accelerations. The frequency effects on the applied alternating accelerations were also investigated in this research. The results show that input waves containing the lower frequency components than the natural frequency are more damageable comparing to that containing higher frequency ones. Besides, the component with lower frequency contributes more to the occurrence of ratcheting. The characteristics of dynamic loading due to base acceleration depend on the loading frequency. The low-frequency acceleration acts like load-controlled loading, while the high-frequency acceleration is close to displacement-controlled loading.

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“…Bree diagram identified ratcheting occurrence conditions under the primary membrane load with secondary bending load. Yamashita et al further developed a theoretical ratchet diagram for rectangular beams subjected to the primary bending load with secondary bending load (Yamashita et al, 1990). However, current methods determining the ratcheting boundary only considers the constant pressure load with varying thermal loads.…”

Section: Introductionmentioning

confidence: 99%

Ratcheting occurrence conditions of piping under sinusoidal excitations

Lyu

Ichimiya

Sasaki

et al. 2020

Mechanical Engineering Journal

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Ratcheting is one of the dominant failure modes under excessive earthquakes and may cause extreme failures of structures (e.g., collapse). We focused on clarifying the ratcheting mechanism of piping under sinusoidal excitations. Both finite element analyses and experiments were conducted on bent solid bars, which represented piping in this study. Seismic ratcheting occurred due to the combined effect of constant external compressive force and cyclic vibrations. The external compressive force acted as a load-controlled load. Vibrations were applied to provide the source of the dynamic load. Characteristics of vibrations between load-controlled and displacement-controlled properties were studied from the viewpoint of the frequency ratio of the forcing frequency to the natural frequency of the piping model. In addition, the influence of supports on the occurrence of ratcheting was also considered. The results showed that the resonance effect was evident in the piping model compared with the beam model due to the limited plastic area in the piping model. The vibration with a lower frequency had load-controlled characteristics. In contrast, the vibration with a higher frequency presented displacement-controlled properties. In terms of the occurrence of ratcheting, providing more supports sometimes increased the possibility of the occurrence of ratcheting under relatively higher forcing frequencies because more supports increased the natural frequency and decreased the frequency ratio.

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A simplified method of evaluating ratcheting in bellows and a test of its validation

Cited by 12 publications

References 3 publications

Uniaxial time‐dependent ratcheting behavior of bronze powder filled polytetrafluoroethylene at room and high temperature

Uniaxial time‐dependent ratcheting behavior of bronze powder filled polytetrafluoroethylene at room and high temperature

Study on ratcheting of beams under the combination of gravity and seismic load

Ratcheting occurrence conditions of piping under sinusoidal excitations

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