Electro-hydraulic servo universal testing machine: Electric - Electronic measurement and electronic feedback signal control, the sensor measures the force value and participates in the stress rate control; the electronic extensometer measures the deformation within the gauge length of the sample and participates in the strain rate control; the displacement sensor (photoelectric encoder) measures the displacement value and participates in the beam displacement rate control. Hydraulic - Hydraulic pressure exerts test force. Servo - three closed-loop control with closed-loop control, is stress rate, stress retention, strain rate, strain retention, beam displacement rate and beam displacement retention. Common models: WAW-300B, WAW-600D, 1000D