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論文
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神宮, 利夫 ; 松本, 浩之 ; 根津, 紀久雄 ; 坂本, 賢治
概要:
application/pdf<br />Journal Article<br />Transducers consisting of a strain gage or accelerometer and piezo-electric sensor are popular instruments used to evaluate dynamic response. Although the observation of transmitted strain by
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means of the strain gage method assures accuracy, it is not convenient to estimate the dynamic response of materials having a large cross-sectional area. On the other hand, there is little restriction in measuring of dynamic response using an accelerometer since it is small and light. It is easy to fabricate the transducer by applying a piezo-electric sensor. However, except for the strain gage method, the technological issues as to whether these are consistent or accurate for the measurements of dynamic response, particularly the impact load, have not been apparent. In this paper, we distinguish the technological issues which may arise in using such dynamic response transducers for measuring the impact load caused by the collision of two round bars or a sphere and flat plate.
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論文 |
論文
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神宮, 利夫 ; 松本, 浩之 ; 根津, 紀久雄 ; 坂本, 賢治
概要:
application/pdf<br />Journal Article<br />In the collision between the flat surface of solid and of a sphere, it can be considered that a high stress will be occur, since an impact load is applied in a small local contact area. If an
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impact stress exceeds the yield stress of a material, the local deformation of the contact surface converts from elastic to plastic flow. Therefore, the impact load may be moderated. It is important when formulating the impact load that the effect of the local plastic deformation of the contact surface on the time history of a load due to impact is investigated. On the other hand, it is revealed by Hertz's theory that the relationship between a force and the amount of approach of both solids during impact is nonlinear. If it is postulated as being linear, there is not little what be able to apply it to analyze the dynamic impact problem. In this paper, the effect of the local displacement behavior in the contact process on the impact load is shown by the experiment of a collision between a plate of mild steel and a high hardness steel ball. The impact load is evaluated by a piezo electric plastic transducer. The limitation which the modified approach of Hertz's theory is valid, are distinguished.
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論文
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神宮, 利夫 ; 松本, 浩之 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />In this paper, the dynamic similarity of transient response caused by the collision between a sphere and a cantilever beam is theoretically investigated and the results are compared with the
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experiments. The theoretical analysis of transient response in a cantilever beam is conducted by the use of classical beam theory and with the aid of a Laplace transform which extends the fast Fourier transform to an inverse transform under the condition that the spheres strike cantilever beams at arbitrary points. The dynamic similarity of a cantilever beam is studied to use those results. In the experiment, the bending strain is measured by a strain gauge cemented to a bar of rectangular cross section of the model or the real thing. It is shown that the variation in bending strain of the model multiplied by the coefficient of similarity is in agreement with the real thing.
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