Marble Plate Research Articles

Experimental study of the strain field development prior to failure of a marble plate under compression : Huang Jiefan; Chen Ganglin; Zhao Yonghong; Wang Ren Tectonophysics V175, N1/3, March 1990, P269–284. (Paper to the symposium on earthquake source processes, 19th IUGG general assembly, Vancouver, 19–21 August 1987)

Experimental study of the strain field development prior to failure of a marble plate under compression : Huang Jiefan; Chen Ganglin; Zhao Yonghong; Wang Ren Tectonophysics V175, N1/3, March 1990, P269–284. (Paper to the symposium on earthquake source processes, 19th IUGG general assembly, Vancouver, 19–21 August 1987)

An experimental study of the strain field development prior to failure of a marble plate under compression

The strain field development prior to failure of a uniaxially compressed marble plate with an inclined central slot is studied experimentally. The whole process of failure development of the specimen is directly monitored and photographed by back illumination. The displacement fields at different stages are recorded with the moire technique and corresponding strain fields are calculated. Test results show that when the specimen is loaded to a certain level, its strain will become concentrated in relatively narrow belts which are potential locations of the impending ultimate failure. The failure process can be roughly divided into five stages: (1) initiation and propagation of primary forward tensile cracks, also known as wing cracks, (2) initiation and propagation of secondary forward tensile cracks, (3) initiation and intensification of shear belts starting from the slot tips and extending in an “X” form toward the four comers of the specimen, (4) initiation and propagation of backward tensile cracks, and finally (5) the ultimate failure. The forward tensile cracks are similar to those previously described in the literature ∗∗ but the backward cracks run in an opposite direction. In this study, four types of ultimate failure are identified: (i) axial splitting along tensile cracks, (ii) shear fracture along shear belts having a similar trend as the slot, (iii) shear fracture along shear belts sub-conjugate to the slot, and (iv) various combinations of splitting and shear fracture. Specimens with infill mortar material in the slot are also tested, where it is found that the mortar suppresses axial splitting. The geophysical and seismological implications of the test result are also briefly discussed.

Experiment and finite element simulation of X-type shear fractures from a crack in marble

Laser holographic interferometry is used to measure the out-of-plane displacement field in the uniaxial compression testing of a marble plate with an inclined crack. The experiment shows that near the tips of the crack, tensile fractures first occur; they propagate curvilinearly, bend toward the axial direction and become stabilized. This agrees well with the usual theory. However, if the crack is an open slot, as the compressive load increases, X-type shear fractures appear near the tips of the slot, propagate in the direction opposite to the tensile fractures and lead to final rupture of the specimen. This phenomenon can be related to the strain softening behavior near the tip of the slot. A mathematical model using finite element analysis for strain softening of elastoplastic material is used to simulate the process and obtain the same result. If the crack is a closed cleavage, the rupture takes place as X-type shear fractures starting from the boundary of the plate.

Spreading of a water drop on a marble surface

Measurements of the wetting contact angle for a marble surface were carried out for two systems: dry marble plate-water drop-saturated water vapour and marble wetted by water-water drop-dry air (in the presence of molecular sieves). The marble plate was placed in a measuring chamber and contact angles were measured after different lengths of time; it was found that their values grew to a maximum which was reached after about 30 min. It was found that when the dry marble plate was placed in saturated water vapour for 24 h the contact angle decreased in comparison with its maximal value. To explain the results obtained, theoretical calculations were made. The theoretical calculations and measurements showed that it was possible to obtain a contact angle greater than zero on a marble surface, depending on the structure and thickness of the water film.

A new method of cutting glass plate, using thermal stress

The property of a brittle material to rupture under thermal stress is utilized to cut glass plate. In the experiments reported, thermal stress is induced by use of a heated nicrome wire — lime glass, flint glass and artificial marble plate are cut by the nicrome wire, which is arranged on the plate along the desired cutting line. The characteristics of the cutting method are: 1. (1) Cutting can be carried out exactly where required, and the cut cross-section is normally smooth; particularly, that of glass shows a mirror finish. 2. (2) Stacked glass plates can be cut simultaneously at many different positions. 3. (3) Cutting along a curve, or a circle, or the cutting of a strip of narrow width from the edge of a plate, can be undertaken with ease. 4. (4) Cutting is independent of the roughness of the surface. 5. (5) The speed of cutting is very high, and the cutting energy is very low.

The so-called puteal in the Capitoline Museum at Rome

The original purpose served by this curious panel of mosaic and marble (plate I), which is decorated with scenes from the life of Achilles, has not yet been determined, nor has any successful attempt been made either to date it or to assign it definitely to any school or centre of art. The mosaic which occupies the centre and corners is probably rightly attributed to the Cosmati, who made the ‘ambon’ in S. Maria in Ara Coeli, of which this panel formed a part. The circular band of marble, decorated in relief, is generally regarded as the top of a puteal or well-head although, as has been observed, it is hardly consistent with the practical sense of the Greeks and Romans to cover with decoration a surface of marble so liable to rough usage. More probably the band formed the border of a large shallow bowl, a possibility not considered heretofore owing to the difficulty of close examination arising out of its post-classical use.