Location

La Jolla, CA

Start Date

1-1-1989 12:00 AM

Description

In the production of fused cast refractory materials there is a need to identify blocks that fail prematurely by breaking during transit or in service as furnace linings for molten metal processing.The MonofraxR L and H type are magnesia-alumina or alumina based refractories.Surface cracks can develop in the casting and cooling steps of the process.There is also some variability in weight due to shrinkage cavities.The goal is to determine statistically which of these observables and other NDE derived parameters are accurate predictors of the performance of these 10 x 30 x 40 cm blocks.The NDE methods should be fast, easy to do, and capable of easy interpretation in the production environment.Vibrational resonance techniques satisfy these requirements. While there are a large range of methods based on the excitation of vibrational modes in a body and measuring its response as a function of time, frequency, and position [1]; the simplest measurement is that of the resonant frequency of a part supported at nodes of a fundamental mode and excited by tapping. Since the entire piece is vibrated, it is a global inspection and does not require the detailed scanning associated with ultrasonic reflections from flaws. However, there are some similarities between the use of vibrational resonance and ultrasonic velocity measurements since they both can be interpreted in terms of the elastic modulus and both have been applied to refractory materials and structural ceramics [2,3].

Volume

8B

Chapter

Chapter 9: Characterization of Materials

Section

Properties

Pages

1687-1691

DOI

10.1007/978-1-4613-0817-1_213

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Failure Prediction of Ceramic Refractories by Discriminant Analysis of Vibrational Resonance Data

La Jolla, CA

In the production of fused cast refractory materials there is a need to identify blocks that fail prematurely by breaking during transit or in service as furnace linings for molten metal processing.The MonofraxR L and H type are magnesia-alumina or alumina based refractories.Surface cracks can develop in the casting and cooling steps of the process.There is also some variability in weight due to shrinkage cavities.The goal is to determine statistically which of these observables and other NDE derived parameters are accurate predictors of the performance of these 10 x 30 x 40 cm blocks.The NDE methods should be fast, easy to do, and capable of easy interpretation in the production environment.Vibrational resonance techniques satisfy these requirements. While there are a large range of methods based on the excitation of vibrational modes in a body and measuring its response as a function of time, frequency, and position [1]; the simplest measurement is that of the resonant frequency of a part supported at nodes of a fundamental mode and excited by tapping. Since the entire piece is vibrated, it is a global inspection and does not require the detailed scanning associated with ultrasonic reflections from flaws. However, there are some similarities between the use of vibrational resonance and ultrasonic velocity measurements since they both can be interpreted in terms of the elastic modulus and both have been applied to refractory materials and structural ceramics [2,3].