Analysis of the buckling moment on rectangular hollow pipe under pure bending load

Not only the circle hollow pipe but also the rectangular hollow pipes are used on offshore structure. In this study, the bending moment was given at both end of pipe. The strength of buckling moment can be reduced by increasing the length. The rectangular pipe models are varying from a/b = 1, 2, 4; a/t = 10, 15, 20 and L/a = 10, 15, 20. On the rectangular pipe which is have larger rectangle area (a/b), have the larger deformation. Vice versa on the rectangular pipe which is have smaller rectangle area (a/b), as though on a/b = 2 and a/b = 4 which is have smaller deformation. The conclude that is the larger one of rectangle area then the oval deformation is large too. The buckling strength will increase with decreasing a/b and deformation at mid span will be increase. The buckling strength decrease with increasing of L/a and a/t. The strength of the buckling moment in the elastic state will decrease with increasing of a/t and a/b. For a/b = 1, the strength of buckling moment will tend to be equal at L/a = 10-20. Pipe with increasing of a/t, L/a and a/b will be elastic.

A Study on Thermal Behavior of Large Seal-Ring

The behavior of seal-ring in the shaft seal which operates on oil film to seal high pressure gas is studied. The experiment on the 60 cm diameter seal-ring shows the slow whirl phenomenon, i.e., the local oil film thickness and that temperature varies with the period of about 100 seconds. The analytical model is formulated and predicts the oval deformation of seal-ring due to hot spots, and that the oval shape rotates slowly but periodically according to the shift of hot spots. Theoretical predictions are confirmed to agree well with the experiment. Also, the effects of some design parameters are described to prevent the relevant slow whirl.

The measurement of arterial pressure in man. I.—The auditory method

In a previous communication we showed that when an artery, exposed in a living animal, is compressed in a glass compression tube full of water (Ringer’s solution), the pulse, distal to the compression, is not obliterated until the pressure of the water is raised just above the systolic pressure of the blood in the artery, whereas when the same artery, placed on bone, wood or glass, is compressed by the bag of Leonard Hill’s pocket sphygmometer, or by the armlet of the sphygmometer, so arranged that it does not embrace the surrounding pulsating tissues, the pulse is abolished by pressures under, and even much under, the diastolic pressure of the blood stream. These facts are correlated with the manner in which the artery is compressed in each case. Enclosed in the compression tube the artery is compressed by the water equally in a circular fashion so that the rise of external pressure, up to the diastolic pressure, has no effect in producing deformation of the artery. Ultimately, when the compression becomes greater than the diastolic pressure, the artery flattens and changes to the oval shape during diastole. It is flattened during systole when the external pressure rises above the systolic pressure. When the carotid artery of the living animal is freed from the surrounding tissues and placed on a watch-glass and compressed by the bag of the pocket sphygmometer, or by the armlet so arranged as not to embrace the pulsing tissues of the neck, the oval deformation sets in at far lower pressures and is complete in relatively thin-walled labile arteries at pressures much under diastolic pressure. Consequently the blood flow is cut down by an external pressure less than diastolic to a mere ineffective trickle of blood, and the pulse is completely damped out. If a branch of the carotid artery distal to the bag were connected with a C-spring manometer, the record would show a progressive lowering of both the systolic and the diastolic pressure almost to zero, till with an external pressure much less than the diastolic pressure in the aorta the pulse was damped out and the blood flow became a trickle.