Matching design for bolted joints based by effective contact radius maximization

To improve the contact state of fixed joints in machine tools, the factors affecting the contact pressure distribution in bolted joints are discussed. The contact pressure distributions on bolted joint interfaces are obtained with finite element contact analysis of single bolted joint models, which can be characterized by Gauss distribution model along the radial direction of the bolt hole. It is shown that the contact pressure increases linearly with the increasing preload while the distribution tendency and area remain unchanged. The contact pressure distribution varies from concentrated to uniform with the increasing clamped part thickness, but the effect gradually weakens. With the increasing bolt diameter, the absolute effective radius increases and the peak pressure appears at the position of 0.8 bolt diameter. Maximizing the effective contact radius and jointed area, the matching relationship between the clamped part thickness and bolt diameter, as well as the maximum distance of adjacent bolts, are gained.