Parallel chord truss: Parallel chord truss is a kind of arch truss, which is characterized in that the chord is composed of several parallel arch nodes, and the nodes between the arch nodes bear the same bending force, so that the stress distribution of the arch line is uniform. ?

Triangular truss: Triangular truss is one of the most common finite element trusses, which consists of three chords, and its force distribution is determined by the parallel concentrated action of triangular internal forces. ?

Broken chord truss: Broken chord truss is a kind of truss of chord arch structure, which is characterized by fracture at the corners of both ends of the chord, which will cause couple effect at the corners, thus affecting the stress distribution of the truss. ?

Distribution characteristics of rod axial force: the distribution characteristics of rod axial force refer to the distribution characteristics of force on the upper end of rod shaft, which is manifested by the generation of force couple at the upper end of frame. The size of force couple is influenced by structural parameters, nodal force and force characteristics of frame.

Truss is a structural system composed of several straight bars hinged at both ends, which only bears node load. Truss structure is widely used in engineering, usually made of steel, reinforced concrete, wood and other materials. It can be used in buildings, bridges and hydraulic structures, and is one of the common structural forms of long-span structures.

Characteristics of truss:

In practical engineering, the stress situation of truss is complicated. When determining the calculation diagram of truss structure, the following assumptions are made: (1) All hinge joints are smooth and frictionless ideal hinge joints. ? (2) Each rod is straight, and the axis of the rod is in the same plane and passes through the center of the hinge point. ? (3) Both the load and the supporting reaction act on the nodes and lie in the plane of the truss.