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PurposeA diffusion-reaction-deformation coupled model is employed and implemented as a user-defined element (UEL) subroutine in the commercial finite element software package ABAQUS.Design/methodology/approachChemical reaction and diffusion are treated as two distinct processes by introducing the extent of reaction and the diffusion concentration as two kinds of independent variables, for which the independent governing equations for chemical reaction and diffusion processes are obtained. Furthermore, an exponential form of chemical kinetics, instead of the linearly phenomenological relation, between the reaction rate and the chemical affinity is used to describe reaction process. As a result, complex chemical reaction can be simulated, no matter it is around or away from equilibrium.FindingsTwo numerical examples are presented, one for validation of the model and another for the modeling of the deflection of a plane caused by a chemical reaction.Originality/value1. Independent governing equations for diffusion and reaction processes are given. 2. An exponential relation between the reaction rate and its driving force is employed. 3. The UEL subroutine is used to implement the finite element procedure.

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Snorkeling equipments have played a vitally important role in various underwater operations, such as military, rescue activities, underwater research, archeology, and so on. However, existing snorkeling styles, represented by mechanical lifting system, artificial diving, and submarine mode (water storage and drainage), still face numerous challenges in the issues of large energy loss, complex structure, or environmental unfriendliness. Especially for small flexible equipments, an efficient and convenient way of snorkeling is of prime importance to various underwater explorations for a long time. Here, for the first time, an automatic snorkeling electronic equipment driven by a self‐breathing flexible aqueous aluminum‐air battery (Self‐BAAAB) which integrates functions of the snorkeling and the electric energy supply is designed. The self‐BAAAB battery consists of naturally inspired spongy sodium polyacrylate (PANa) hydrogel that acts as a flexible electrolyte and vertical N–O doped graphene fiber (NOGF) as an ORR/OER/HER trifunctional electrocatalyst. Benefited from the trifunctional catalytic properties and the aluminum metal stripping, the Self‐BAAAB consumes oxygen gas in the routine discharge process while the gas in turn is released during the charging process due to electrolysis of water in the super‐absorbing hydrogel, which triggers the sharp density variation of Self‐BAAAB, driving the “automatic snorkeling” feature of electronic equipment underwater. This work provides new insights into the design of the snorkeling electronic equipments and would promote the high efficiency of underwater operations, especially in a complex environment.

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