群馬大学大学院理工学府知能機械創製部門材料力学研究室

The Jomon ware is the most valuable devices which changed the lifestyle of Jomon people. Although the study as a cultural art on Jomon ware has been carried out very much, the study as a material strength of it is rare because the destructive testing of it is difficult. The purpose of this study is to evaluate the Jomon ware from a point of view of strength of materials. The influence of mixing admixture of mica and chaff on strength properties of the ware and that of changing firing time were examined. Four point bending tests are carried out for measuring bending strength and fracture toughness. As a result, bending strength and fracture toughness become stronger by mixing admixture and changing firing time.

Although the study as a cultural anthropology on Jomon ware has been carried out very much, the study on a material strength of it is rare because the destructive testing of it is difficult. The purpose of this study aims to examine the strength of the Jomon ware materials.Four point bending tests are carried out for measuring bending strength and fracture toughness. As a result, bending strength and fracture toughness become stronger by reducing the defects such as cracks and holes.

The Jomon era is the former Japanese era which is about 10000 years. Various cultures had been evolved in the Jomon era. The lifestyle of Jomon people was changed in the Jomon era. The Jomon ware is one of the devices in the Jomon era. The purpose of this study is to evaluate the Jomon ware from a point of view of strength of materials. The influence of the mixing ratio of clay, sand and mica on strength properties of the pottery was examined. The research methods are observation of structure, four point bending test and fracture toughness test. From the result, we quantitatively evaluate the technical knowledge which Jomon people had.

Invention of Jomon pottery enabled people to cook and reserve food. The invention changed their life style. It has interesting decoration in terms of not only from history, culture but also from the study of strength of material. The purpose of this study is to research in term of materials mechanics. Four point bending test specimens are used for measuring bending strength and fracture toughness. As a result, the bending strength and fracture toughness increase with increasing in weight ratio of clay and that of mica. And mica has a role to promote blanching during crack propagation.

Jomon pottery has evolved with the times. But Jomon pottery is researched from only archaeological viewpoint. The purpose of present study is to evaluate the Jomon pottery from a viewpoint of materials strength. The influence of mixing ratio of clay and sand on strength properties of the pottery materials was examined. We produced the specimen of pottery materials by changing the mixing ratio. By using the specimens, four point bending test, fracture toughness test and observation of cross-section were performed. As a result, the bending strength and fracture toughness was increasing with decreasing the mixing ratio of the sand. Accumulated technology and knowledge of the people of Jomon period was valid for materials strength improvement.