The climbing microrobots have attracted growing attention due to their promising applications in exploration and monitoring of complex, unstructured environments. Soft climbing microrobots based on muscle-like actuators could offer excellent flexibility, adaptability, and mechanical robustness. Despite the remarkable progress in this area, the development of soft microrobots capable of climbing on flat/curved surfaces and transitioning between two different surfaces remains elusive, especially in open spaces. In this study, we address these challenges by developing voltage-driven soft small-scale actuators with customized 3D configurations and active stiffness adjusting. Combination of programmed strain distributions in liquid crystal elastomers (LCEs) and buckling-driven 3D assembly, guided by mechanics modeling, allows for voltage-driven, complex 3D-to-3D shape morphing (bending angle > 200°) at millimeter scales (from 1 to 10 mm), which is unachievable previously. These soft actuators enable development of morphable electroadhesive footpads that can conform to different curved surfaces and stiffness-variable smart joints that allow different locomotion gaits in a single microrobot. By integrating such morphable footpads and smart joints with a deformable body, we report a multigait, soft microrobot (length from 6 to 90 mm, and mass from 0.2 to 3 g) capable of climbing on surfaces with diverse shapes (e.g., flat plane, cylinder, wavy surface, wedge-shaped groove, and sphere) and transitioning between two distinct surfaces. We demonstrate that the microrobot could navigate from one surface to another, recording two corresponding ceilings when carrying an integrated microcamera. The developed soft microrobot can also flip over a barrier, survive extreme compression, and climb bamboo and leaf.

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This study examines an extended method to obtain the parameters in the Generalized Incremental Stress State Dependent Damage (GISSMO) model. This method is based on an iterative Finite Element Method (FEM) method aiming at predicting the fracture behavior considering softening and failure. A large number of experimental tests have been conducted on four different alloys (7003 aluminum alloy, ADC12 aluminum alloy, ZK60 magnesium alloy and 20CrMnTiH Steel), here considering tests that span a wide range of stress triaxiality. The proposed method is compared with the two existing methods. Results show that the new extended Iterative FEM method gives the good estimate of the fracture behaviors for all four alloys considered.

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The kinetics of transesterification of methyl acetate with ethylene glycol catalyzed by acidic ion‐exchange resin NKC‐9 is investigated in detail. The effects of reaction temperature, catalyst loading, and initial reactants molar ratio on the reaction rate are studied in the absence of mass transfer resistance. The kinetic equation is obtained by utilizing the PH model to correlate the experimental data. Then a distillation process is designed to produce high‐purity ethylene glycol diacetate, which includes a reactive distillation column, an extractive distillation column, and a solvent recovery column. The extractive distillation column and solvent recovery column are used to recycle excess methyl acetate and entrainer. Operational and structural parameters are optimized by minimizing the total annual costs (TAC) while meeting the product specifications.

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