Devices for Measurement and Specimen Preparation

Determination of Chemical Composition of Heterogeneous Matters using Energy Dispersive X-ray spectrometry

In obtaining reasonable measurements, it is important to prepare the specimens perfectly. Sometimes, it becomes a part of scientific art rather than a pure science. We mastered techniques to obtain the chemical composition of heterogeneous compounds via energy dispersive X-ray spectrometry and electron microscopy. We compare the analysis results with conventional volumetric analysis and atomic absorption spectroscopy to assess the reliability of our techniques.

Measurement of Lateral Deformation in Large Deformation Uniaxial Tests

Measurement of lateral deformation in large deformation uniaxial tests is a difficult task. Specially, in testing the mechanical behavior of rubbers, the incompressibility assumption is used to predict the deformed cross section under loading and thereby to calculate the true stress. There are, however, cases where rubbers can undergo considerable volumetric deformation in large strain experiments. Microstructural investigation through a scanning electron microscope conducted on a void-filled natural rubber specimen clarify the effect of voids on the compressibility feature. The microstructure of the natural rubber is observed qualitatively and quantitatively in uniaxial tension and compared to the microstructure in the undeformed condition. We confirmed the existence of the compressibility feature in the void-filled rubber from a microstructural viewpoint.

The findings indicated the necessity of accurate measurement of the deformed cross section in mechanical tests to obtain the true stress. To this end, an experimental setup capable of measuring the deformed cross section of the rubber specimens subjected to large uniaxial compression was developed. To do this, the accuracy of laser beams is utilized for measurement of distance and a mechanical jig is developed to synchronize the movement of laser transducer with the vertical crosshead of the load cell of a computer-controlled servo-hydraulic testing machine. Thus the constraints associated with the conventional strain gages in measuring large strains were overcome.

Testing of Spun Reinforced Concrete Pipes
We have developed the hydraulic jack controlled Test Set-up to assure the quality of Vitrified Clay Pipes and Spun Reinforced Concrete Pipes as per International Standards that approves Three point Loading test systems. In the set-up full scale pipes up to 1.8m in diameter and 1.8m in length can be tested.