Design of Composite Spirally Reinforced Rods

Abstract

Rod elements made of fibrous composites are a frequent component of spatial trussed designs thanks to a set of specific advantageous properties, including low linear thermal expansion coefficient (LTEC), good radioparent features and some other. These advantages are however bounded by known drawbacks, most unfavorable among which is anisotropy of elastic and strength characteristics. High tensile properties of the material in reinforcement direction are in contradiction with poor transversal characteristics, low interlayer shear modulus, and etc. This, in its turn condition impaired strength of rods from unidirectional composites at a lengthwise compression and relatively low critical load values. Such rods start to break and loose their bearing capacity much earlier than the material strength and bearing capacity of its fibers are exhausted being dependent upon accumulation of microdamages in the bulk. Fracture of rods of unidirectional composites occurs as a result of delamination of their fibers arising from binder cracking and bulging of individual unstable fibers.