Stress-based topology optimization of compliant mechanisms using nonlinear mechanics

Capasso, Gabriele; Morlier, Joseph; Charlotte, Miguel; Coniglio, Simone

doi:10.1051/meca/2020011

Cited by 12 publications

(4 citation statements)

References 55 publications

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“…where the summation is cyclic, such that ≔ . The constraints for the optimization process are imposed on both the input displacements and the total strain energy: the maximum stroke of the PEAs is limited to max = 60 μm, and the stroke is smaller in practice because of the assembly error; the strain energy, , is also constrained, with a coarse upper bound, , in a manner similar to that described in previous research [37,38] to avoid fatigue failures. As a result, the TO problem of maximizing can be formulated as follows:…”

Section: Topology Optimization Processmentioning

confidence: 99%

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Integrated Development of a Topology-Optimized Compliant Mechanism for Precise Positioning

Zhu

2022

Actuators

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A scheme for modelling and controlling a two-dimensional positioning system with a topology-optimized compliant mechanism is presented. The system is designed to ensure a relatively large workspace and exhibit robustness against system nonlinearities. A detailed design procedure based on topology optimization is presented, and a nonlinear description of the designed mechanism is developed as a starting point for further precise position control. The theoretical model is shown to be suitable for a considerably larger working range without losing consistency. A backstepping controller is employed to manipulate the nonlinearities in the model resulting from the geometrical and material nonlinearity of the mechanical structure. The hysteresis of the piezoelectric actuator is also taken into consideration. An experimental verification of the controller demonstrates that the proposed design approach improves the performance of compliant mechanism and satisfies the needs for precision positioning.

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Section: Topology Optimization Processmentioning

confidence: 99%

“…Since the evaluation of the gradients only requires the accuracy of a tangent space approximation [37], the approximated can be given by the following:…”

Section: Topology Optimization Processmentioning

confidence: 99%

Integrated Development of a Topology-Optimized Compliant Mechanism for Precise Positioning

Zhu

2022

Actuators

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“…Huang et al [14] focused also on structural design under displacement loading. Capasso et al [15] used nonlinear mechanics to analyze the stress-based topology optimization of compliant mechanisms. A similar work was proposed by Leon et al [16], who also addressed the topology design of compliant mechanisms with material and geometric nonlinearities using stress constraints.…”

Section: Introductionmentioning

confidence: 99%

On the topology design of a mechanical heterogeneous specimen using geometric and material nonlinearities

Gonçalves

Andrade‐Campos

Thuillier

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Material characterization and the calibration of constitutive models play an important role in the majority of the forming processes nowadays. For an accurate virtualization of the processes, the material mechanical behavior needs to be known a priori. The classical characterization procedure involves carrying out several standard mechanical tests to identify the required information about the material. However, this procedure turns out to be expensive and time-consuming. Heterogeneous mechanical tests have been used to overcome this issue. By providing richer information with a reduced number of tests, their use can enhance the actual material characterization process. This work aims at making a significant contribution towards this goal by designing a heterogeneous mechanical test using topology optimization. A specimen topology is obtained with a heterogeneous displacement field by applying the theory of compliant mechanisms. Due to the large displacements considered, a geometrically nonlinear finite element analysis and a topology optimization procedure are proposed. Material nonlinearity is taken into account as well, to design solutions closer to reality. An optimal mechanical test with a highly heterogeneous strain field is obtained and evaluated, considering its diversity, using mechanism theory and a mechanical indicator.

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“…Félix et al [10] considered the wing's self-weight, besides an aerodynamic load, to design it topologically. Capasso et al [11] employed TO to design a morphing structure made of a hyperelastic material.…”

Section: Introductionmentioning

confidence: 99%

A Sequential Approach for Aerodynamic Shape Optimization with Topology Optimization of Airfoils

Martínez

Afonso

Rodrigues

et al. 2021

MCA

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The objective of this work is to study the coupling of two efficient optimization techniques, Aerodynamic Shape Optimization (ASO) and Topology Optimization (TO), in 2D airfoils. To achieve such goal two open-source codes, SU2 and Calculix, are employed for ASO and TO, respectively, using the Sequential Least SQuares Programming (SLSQP) and the Bi-directional Evolutionary Structural Optimization (BESO) algorithms; the latter is well-known for allowing the addition of material in the TO which constitutes, as far as our knowledge, a novelty for this kind of application. These codes are linked by means of a script capable of reading the geometry and pressure distribution obtained from the ASO and defining the boundary conditions to be applied in the TO. The Free-Form Deformation technique is chosen for the definition of the design variables to be used in the ASO, while the densities of the inner elements are defined as design variables of the TO. As a test case, a widely used benchmark transonic airfoil, the RAE2822, is chosen here with an internal geometric constraint to simulate the wing-box of a transonic wing. First, the two optimization procedures are tested separately to gain insight and then are run in a sequential way for two test cases with available experimental data: (i) Mach 0.729 at α=2.31°; and (ii) Mach 0.730 at α=2.79°. In the ASO problem, the lift is fixed and the drag is minimized; while in the TO problem, compliance minimization is set as the objective for a prescribed volume fraction. Improvements in both aerodynamic and structural performance are found, as expected: the ASO reduced the total pressure on the airfoil surface in order to minimize drag, which resulted in lower stress values experienced by the structure.

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Stress-based topology optimization of compliant mechanisms using nonlinear mechanics

Cited by 12 publications

References 55 publications

Integrated Development of a Topology-Optimized Compliant Mechanism for Precise Positioning

Integrated Development of a Topology-Optimized Compliant Mechanism for Precise Positioning

On the topology design of a mechanical heterogeneous specimen using geometric and material nonlinearities

A Sequential Approach for Aerodynamic Shape Optimization with Topology Optimization of Airfoils

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