| 摘要 |
PURPOSE:To contrive to improve bending rigidity and at the same time to save weight by a structure wherein both the outer and inner surface layers of the hollow cylindrical mast of a wind surfing board are made of glass fiber, while its intermediate layer is made of the combination of glass fiber and carbon fiber with higher modulus of elasticity that glass fiber. CONSTITUTION:The mast of a wind surfing board consists of the inner surface layer made of epoxy resin reinfored with one layer of glass fiber 7, the intermediate layer made of epoxy resin reinforced with two layers of glass fiber 7 and carbon fiber 6 arranged alternately, and the outer surface layer 5 made of epoxy resin reinforced with two layers of glass fiber 7. Said mast can be improved its bending rigidity as compared with a mast made of glass fiber only and yet can prevent an accident of broken-mast at the overturning of the boat from occurring as compared with a mast made of carbon fiber only and furthermore can improve the manageability of the boat. |
