• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.754-758
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• 2002

According to the enlargement of production facilities and structures, the requirements of high-capacity load cells are increased for monitoring the process conditions in many fields. Generally, however, the accuracy of the column-type high-capacity load cells is not enough due to the geometric nonlinearity. It is supposed to result from the fact that the whole spring element is under high-level stress for the uniform strain field. In this paper, a new shape of spring element is developed which utilizes the stress concentration. As a design criterion, an object function which quantifies the degree of nonlinearity is defined and optimized by use of response surface modeling. As a result, the weight of the spring element is reduced shout 50% in comparison to the conventional shape. The bonding positions of stain gages are found. which show theoretically zero geometrical nonlinearity, while the ratio of overload protection is reduced from 130% to 125% Also it is shown that the response surface method is very efficient in the optimization approach by use of FEM.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.149-154
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• 2001

In case of high capacity load force as millions of tons, it is difficult to measure the force with load cell. But we can measure and calculate the force with applied pressure and ram area of hydraulic jack. The 5,200 ton compression load tester is composed of thirteen hydraulic jack with 400 ton capacity. This paper explains the method of measuring the vertical compression load and provides characteristics of unit jack, and displacement of upper structure under maximum load condition.