Four-point bending test device for full-size metal composite tube

The invention relates to a four-point bending test device for a full-size metal composite tube. The four-point bending test device for the full-size metal composite tube mainly comprises a base, two load supporting columns, clamping buckles for a detected metal composite tube, two loading oil cylinders, a controller, a sensor, a strain foil and a strain gauge, wherein intervals between the two loading oil cylinders and the adjacent load supporting columns are equal; the sensor is used for transmitting the pressure and stroke of each loading oil cylinder to the controller; and the strain foil transmits the local strain and stress size of the detected metal composite tube to the strain gauge. According to the structure, the whole full-size metal composite tube can be tested; the ends of the piston rods of the loading oil cylinders are hinged with the clamping buckle, so that the clamping buckle can be automatically changed and regulated along with a bending angle of a steel tube; and the clamping buckles for the detected metal composite tube can longitudinally rotate relative to the load supporting columns, so that a clamp can be always in surface contact with the steel tube. Therefore, the four-point bending test device for the full-size metal composite tube has the characteristics of simple structure, reasonable design and convenience in operation and application, and can detect the strain size and the stress size.