Folding analysis of reversal arch by the tangent stiffness method

This paper presents the tangent stiffness method for 3-D geometrically nonl inear folding analysis of a reversal arch. Experimental tests are conducted to verify the numerical analysis. The tangent stiffness method can accurat ely evaluate the geometrical nonlinearity due to the element translating as a rigid body, and the method can exactly handle the large rotation of the element in space. The arch in the experiment is made from a thin flat bar, and it is found that the folding process of the arch may be captured exactl y by the numerical analysis with a model consisting of only 18 elements wit h the same properties.