Benliang Zhu

Bio: Benliang Zhu is an academic researcher from South China University of Technology. The author has contributed to research in topics: Topology optimization & Compliant mechanism. The author has an hindex of 18, co-authored 76 publications receiving 987 citations. Previous affiliations of Benliang Zhu include Kyoto University & University of Oldenburg.

Design of buckling-induced mechanical metamaterials for energy absorption using topology optimization

Abstract: A novel design concept for buckling-induced mechanical metamaterials for energy absorption is presented. The force-displacement curves of the mechanical metamaterials are analyzed according to the curves of their unit cells, and the energy-absorbing characteristics of mechanical metamaterials are evaluated. Two topology optimization models are proposed. One maximizes the buckling-induced dissipated energy to facilitate the design of metamaterials with high energy absorption and low elastic strain energy. The other maximizes the dissipated energy with a constraint that the mechanical metamaterials should be self-recoverable. An energy interpolation scheme is employed to avoid numerical instabilities in the geometric nonlinear finite element analysis. A two-phase algorithm is proposed to find the optimized result from a uniform initial guess, and sensitivity analysis is performed. The optimized design has a larger amount of buckling-induced dissipated energy than the previously proposed structural prototypes. Moreover, the self-recoverable mechanical metamaterial is successfully designed by topology optimization.

Mechanical Structural Design of a Piezoresistive Pressure Sensor for Low-Pressure Measurement: A Computational Analysis by Increases in the Sensor Sensitivity.

Abstract: This paper proposes a novel micro-electromechanical system (MEMS) piezoresistive pressure sensor with a four-petal membrane combined with narrow beams and a center boss (PMNBCB) for low-pressure measurements. The stresses induced in the piezoresistors and deflection of the membrane were calculated using the finite element method (FEM). The functions of the relationship between the dimension variables and mechanical performance were determined based on the curve fitting method, which can provide an approach for geometry optimization of the sensor. In addition, the values in the equations were varied to determine the optimal dimensions for the proposed membrane. Then, to further improve the sensitivity of the sensor, a series of rectangular grooves was created at the position of the piezoresistors. The proposed diaphragm was compared to existing diaphragms, and a considerable increase in the sensitivity and a considerable decrease in nonlinearity error could be achieved by using the proposed sensor. The simulation results suggest that the sensor with the PMNBCB structure obtained a high sensitivity of 34.67 mV/kPa and a low nonlinearity error of 0.23% full-scale span (FSS) for the pressure range of 0⁻5 kPa. The proposed sensor structure is a suitable selection for MEMS piezoresistive pressure sensors.

Hydrodynamic dispensing and electrical manipulation of attolitre droplets

Abstract: Dispensing and manipulation of small droplets is important in bioassays, chemical analysis and patterning of functional inks. So far, dispensing of small droplets has been achieved by squeezing the liquid out of a small orifice similar in size to the droplets. Here we report that instead of squeezing the liquid out, small droplets can also be dispensed advantageously from large orifices by draining the liquid out of a drop suspended from a nozzle. The droplet volume is adjustable from attolitre to microlitre. More importantly, the method can handle suspensions and liquids with viscosities as high as thousands mPa s markedly increasing the range of applicable liquids for controlled dispensing. Furthermore, the movement of the dispensed droplets is controllable by the direction and the strength of an electric field potentially allowing the use of the droplet for extracting analytes from small sample volume or placing a droplet onto a pre-patterned surface. Dispensing small droplets is essential to many ink printing, chemical and biological technologies, but the conventional orifice-based methods fail when the size of droplets approaches sub-micrometre range. Here, Zhang et al.show dispensing of viscous droplets down to attolitre in a controllable way.

Design of single-axis flexure hinges using continuum topology optimization method

Abstract: The design of compliant hinges has been extensively studied in the size and shape level in the literature. This paper presents a method for designing the single-axis flexure hinges in the topology level. Two kinds of hinges, that is, the translational hinge and the revolute hinge, are studied. The basic optimization models are developed for topology optimization of the translational hinge and the revolute hinge, respectively. The objective for topology optimization of flexure hinges is to maximize the compliance in the desired direction meanwhile minimizing the compliances in the other directions. The constraints for accomplishing the translational and revolute requirements are developed. The popular Solid Isotropic Material with Penalization method is used to find the optimal flexure hinge topology within a given design domain. Numerical results are performed to illustrate the validity of the proposed method.

Buckling-induced smart applications: recent advances and trends

Abstract: A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.