Small Compressive Force Research Articles

Studies on friction materials of automobile. 1st report Squeal of disc brake pad.

A device in which the sliding interface between a friction material and a brake disc can be observed directly, was developed to investigate the phenomenon of brake squeal with reference to the composition and method of manufacturing the disc brake pad. The results of investigation show that, in a disc brake pad which is liable to squeal, scales of thermally-decomposed material are produced easily on the frictional surface at a low temperature and with a small compression force. It was also ascertained that, when the quantity of inorganic substances in a brake pad is increased, the brake pad becomes liable to squeal; and that, when the void content of the brake pad is increased, the rate of generation of thermally-decomposed material on its frictional surface drops and the brake pad is very unlikely to squeal. These results prove that the degree of brake squeal is governed by the rate of deposition of thermally-decomposed materials on the frictional surface.

DEFORMATION TESTING OF FOODS: III. Effect of Size and Shape on the Magnitude of Deformation

AbstractSlabs of uniform agar gels were cut into standard shapes of various sizes and their deformation under a small compressive force was measured in an Instron Universal Testing machine. The deformation of rectangular solids and regular cylinders with vertical axes was found to be directly proportional to the specimen height and inversely proportional to the cross‐sectional area. The deformation of regular cylinders with horizontal axes was inversely proportional to the length and was a linear function of the diameter. Deformation of spheres first increased to a maximum, then decreased as the diameter increased giving an inverted V‐shaped curve. The diameter at which the maximum deformation of spheres occurred depended on the agar concentration in the gel and the magnitude of the deforming force.

Deformation Testing of Foods. 2. A Simple Spring Model of Deformation

SUMMARY— A model system is described which closely represents the deformation of a food as it is squeezed in the hand. The model consists of a set of true springs of differing heights and with differing Hooke's constants arranged in parallel. One or more springs are required to represent a given food depending upon the degree of curvilinearity of the force‐compression curve of the food. No dashpots are needed in this simple model. The one restriction on the model is that it is intended to represent the physical response of the food to a single compression. A graphical method for measuring the number, size and Hooke's constants of the springs in the model is described. The spring model shows that with some foods at least, small compression forces measure differences in softness better than large forces.