TECHNOLOGY NEWS: TESTING
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Zwick’s custom-built biaxial system tests soft materials used in the development of what is being hailed the world’s first soft-bodied robot. It can determine the constitutive functions for the in-plane response of isotropic and anisotropic materials.
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One of the hottest trends in robotics today is the push to develop robots that imitate the movements of natural organisms. But to build a flexible robot that can move in that manner, it is necessary to use soft components and to gain an understanding of how soft materials react to stress. For that, researchers at Tufts University in Boston, MA, USA, are using a biaxial testing machine from Zwick GmbH & Company KG (Ulm, Germany; www.zwick.com) to evaluate biological and engineered materials for the development of what is reportedly the world’s first soft-bodied robot.
The researchers are currently working on developing a robot that moves like a caterpillar. Obviously, it cannot be made from traditional hard materials. Instead, it needs to be based on elastic materials such as silicone. To test the soft materials used to develop the caterpillar-inspired robot, the Zwick Roell biaxial testing machine characterizes isotropic and anisotropic elastomers, helping the researchers model the behaviour of the material.
The testing machine is equipped with four independently controlled linear actuators with 2 kN capacity. Each actuator has a loading fixture for applications of tensile or compressive loads to the test sample and a dedicated load cell. A video extensometer that is rigidly fixed to the machine frame allows for noncontact strain measurements of materials that undergo medium to large deformations. The extensometer can capture axial and transverse trains simultaneously in separate input channels.
According to Luis Dorfmann, who heads the mechanical material characterization performed at the Soft Materials Characterization Laboratory at Tufts’ Advanced Technology Laboratory, the Zwick machine has been invaluable to their research because it requires such specialized equipment to understand and characterize anisotropic materials. Principal investigator on the project and professor of biology at the Tufts School of Arts & Sciences and School of Engineering, Barry Trimmer says a robot with the ability to move in a manner similar to a living animal could “make dangerous surgeries safer.” Tufts’ Soft-body robot measures approximately 12 in. long and is made of silicone elastomer. Potential applications for the innovative soft-body robot include medical diagnosis and treatment, and manufacturing.
