Dynamic response of strain gages up to 300 kHz

In engineering mechanisms, solid bodies frequently come to a contact with a variety of geometric and kinematic situations. There has been a trend to express the interaction of the contacted bodies in the form of equivalent interface forces. The interface force represents the level of load transferred from one body to another. In a static or quasistatic contact problem, the interface forces could be sensibly evaluated by integrating the normal and the shear stresses over the common interfaces. In a dynamic contact, the interface stresses and subsequently the interface forces happen to be more complicated. They are, furthermore, affected by other parameters such as inertia forces, stress waves propagation, the material strain rate dependency and damping. This paper reports interface forces recorded in a series of experimental impact tests on axially pre-compressed steel tubes along with those from the numerical simulations of the tests. To monitor the so called impact loads, two small steel rings as load cells have been built in the striker. Based on the experimental and numerical results, the concept of equivalent interface forces in the impacted tubes has been verified. It has been highlighted that the interface forces (or the impact loads) may vary on the striker or the specimen themselves, depending on the measuring locations. Effects of axial compressions on the interface forces picked up by the striker load cells, impact loads imparted to the specimen supports and on the impact duration have been discussed. It has been reported that the initial compression applied to the tubes does not remain constant during and after the impact event. The amount of variations also depends on the initial level of the tube compression.

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“…These gauges were recommended by the manufacturer for dynamic applications and were also consistent with Ueda and Umbera's [19] findings.…”

Section: General Outputsmentioning

confidence: 93%

Interface Forces in Laterally Impacted Steel Tubes

2008

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“…As can be observed, the reconstructed and actual curves compare very favourably. In the authors' opinion, the differences are to be attributed to the measurement method rather than to the reconstruction procedure.Finally the procedure was repeated using the data drawn from Ueda and Umeda [13]. 2 In this case there is excellent agreement between the actual and reconstructed curves (Figure 4).…”

mentioning

confidence: 85%

“…Finally the procedure was repeated using the data drawn from Ueda and Umeda [13]. 2 In this case there is excellent agreement between the actual and reconstructed curves (Figure 4).…”

Section: Validationmentioning

confidence: 98%

An Algorithm for the Input along a Davies’ Bar

Vallascas

Matta

2006

Strain

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“…In the early 80s of last century, Robert D [1] in ENDEVCO corporation, Togami [2] and Ueda [3][4][5] had introduced the operation system for accelerometer calibration in the range of 10,000 g to greater than 100,000 g. This system works based on a Hopkinson bar, and calibration of an accelerometer is based on a strain gauge measurement of the wave. Li et al [6] also presents the modified Hopkinson bar system, this system can calibrate the accelerometer in a range from 5,000 g to 200,000 g. In this system, a half-sine acceleration pulse is obtained by impacting a parabolic pointed projectile.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, a more easy measuring method has been proposed, that is, we base on such a fact, the acceleration pulse is always located in first half of a loading strain pulse in the Hopkinson shock test [1][2][3][4][5][6], and combining with the relation between projectile shape and strain wave, two coaxial projectiles (outer circular tube and inner cylinder) are always fired by a single gun barrel during whole operation. This replace the coaxial double gun barrel, and the synchronization impact on the end surface of the bar is effectively ensured, so it is much more convenient for dynamic linearity measurement.…”

Section: Introductionmentioning

confidence: 99%

One testing method of dynamic linearity of an accelerometer

Lei

Guo

Tan

et al. 2015

EPJ Web of Conferences

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Abstract. To effectively test dynamic linearity of an accelerometer over a wide rang of 10 4 g to about 20 × 10 4 g, one published patent technology is first experimentally verified and analysed, and its deficient is presented, then based on stress wave propagation theory on the thin long bar, the relation between the strain signal and the corresponding acceleration signal is obtained, one special link of two coaxial projectile is developed. These two coaxial metal cylinders (inner cylinder and circular tube) are used as projectiles, to prevent their mutual slip inside the gun barrel during movement, the one end of two projectiles is always fastened by small screws. Ti6-AL4-V bar with diameter of 30 mm is used to propagate loading stress pulse. The resultant compression wave can be measured by the strain gauges on the bar, and a half -sine strain pulse is obtained. The measuring accelerometer is attached on the other end of the bar by a vacuum clamp. In this clamp, the accelerometer only bear compression wave, the reflected tension pulse make the accelerometer off the bar. Using this system, dynamic linearity measurement of accelerometer can be easily tested in wider range of acceleration values. And a really measuring results are presented.

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Dynamic response of strain gages up to 300 kHz

Cited by 20 publications

References 9 publications

Interface Forces in Laterally Impacted Steel Tubes

Interface Forces in Laterally Impacted Steel Tubes

An Algorithm for the Input along a Davies’ Bar

One testing method of dynamic linearity of an accelerometer

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