The objective of the present experimental work is to obtain an appropriate welding parameter on pulsed current gas tungsten arc welding (GTAW) ferritic stainless steel AISI 409L with a thickness of 4.5 mm. Frequency affected penetration, and the ratio of bead width to penetration (aspect ratio) is the main objective of the research. A Taguchi L9 orthogonal array with three level four factors was chosen to execute the bead on plate welding. It leads to optimize the input process parameters on main effect plot via analysis of variance, and it has imposed to determine their contribution level of each parameter with respect to responses. Taguchi optimized conditions for butts weld with the pulsed TIG and its surface morphology, and mechanical characteristics of AISI 409L weld was investigated. A full penetration with an optimal aspect ratio was accomplished using high‐frequency pulsing, according to the findings. The mechanical properties were characterized using Vickers microhardness and tensile tests on the base material and weld metals. Microstructural study revealed that these variables have a greater impact on the bead profile. Pulsed TIG showed maximum UTS of 445 MPa and a minimum of 385 MPa, with an average of three samples of 415 MPa. The weld metal in all of the zones had influenced superior tensile strength (UTS) as compared to base metal, according to the findings. The obtained strain percentage for both butt and TIG welds, however, was smaller than that of the parent metal. The formation of martensitic was attributed for the higher tensile strength with minimized ductility of the pulsed TIG welds. Furthermore, results on the hardness are in concurrence with the tensile experiments, as the zone for fusion has a higher hardness than the base metal. Corrosion behavior of the parent metal and welded specimen was analyzed using a potentio‐dynamic polarization technique. The electrochemical behavior of base material and weld samples confirmed that the overall corrosion resistance is better in parent material than the other zones.

Untethered annelids-inspired soft robots can be used in space-confined compliant interactions where remote actuation is necessary. In contrast to their fully-soft counterparts, incorporating origami concepts can streamline modeling and control while maintaining compliance. However, more comprehensive untethered locomotions from a single deployable robot remain research challenges, and there are only limited motion generation mechanisms available. This paper presents the design and actuation of a caterpillar-inspired biomimetic origami robot prototype. We created an open triangular spring model by the programmable origami backbone for its stability and tunable elasticity. Remotely actuation with internal and external permanent magnets can achieve various types of origami terrestrial locomotion. The prototype can deform and compress up to 26.7 % of its original length, and offer six different types of locomotion capabilities, demonstrating its versatility. A description of the design, programmable crease analysis, and actuation method of the robot is provided in this work. We further analyzed and demonstrated its various motion and functional capabilities and validated various performance parameters such as speed and force bearing capabilities. The normalised velocity of the proposed prototype (0.10 to 0.15) is comparable to most of the speeds achieved by similar motions in other representative works as covered in the paper, demonstrating that versatile motions can be achieved without sacrificing speed performance.

Shape-memory Nitinol holds burgeoning promise as smart actuators due to its effective resilience, high energy density, and scalability for a myriad of mesoscale machines and robotic applications. However, the higher actuation temperature and prolonged cooling time for a cyclic response make Nitinol precarious and less appealing for commercial use. On the contrary, hydrogels belong to the three dimensional (3D) polymer family where the bulk of the matrix encapsulates water (≈80–90 wt%) constituting a compelling heat-trapping medium. In this paper, we demonstrate a novel self-cooling mechanism comprising a Hydrogel-matrix Encapsulated Nitinol Actuator (HENA) where the heat emitted due to the high temperature (200–400 °C) of Nitinol is trapped in the hydrogel-matrix, maintaining a surface temperature of 20–22 °C. For quantitative analysis, we performed control tests with the state-of-the-art Silicone Elastomer Nitinol Actuator (SENA) which maintained a three times or higher temperature profile (65–90 °C) than its HENA counterpart. HENA is able to entrap 85% heat for actuation of 200 cycles while SENA dissipates the same amount in the first cycle. For impending biomedical applications, HENA with a single Nitinol wire shows a bending displacement up to 45% of its length for trans-oral navigation purposes. A HENA soft robotic gripper with two Nitinol wires can carry delicate, low-melting-point food items (e.g. cheese, chocolate, tofu etc.) with different morphologies that weigh up to 450% of its own weight.