Conventional mechanisms provide a defined mobility, which expresses the number of degrees of freedom of the mechanism. This allows the system to be driven by a low number of control outputs. This property is virtually retained in the case of compliant mechanisms with lumped compliance, which are obtained by replacing the conventional hinges by solid-state ones. Compliant mechanisms with distributed compliance have, in general, an infinite number of degrees of freedom and therefore cannot guarantee defined kinematics. In this paper the concept of compliant mechanisms with selective compliance is introduced. This special class of compliant mechanisms combines the advantages of distributed compliance with the easy controllability of systems with defined kinematics. The task is accomplished by introducing a new design criterion based on a modal formulation. After this design criterion has been implemented in an optimization formulation for a formal optimization procedure, mechanisms are obtained in which a freely chosen deformation pattern is associated with a low deformation energy while other deformation patterns are considerably stiffer. Besides the description of the modal design criterion and the associated objective function, the sensitivity analysis of the objective function is presented and an application example is shown.

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Classical beam models do not account for partial restraint of anticlastic bending and are therefore inherently inaccurate. This article proposes a modification of the exact Bernoulli–Euler equation which allows for an exact prediction of the beam's deflection without the need of two-dimensional finite element calculations. This approach offers a substantial reduction in the computational effort, especially when coupled with a fast-solving schema like the circle-arc method. Besides the description of the new method and its validation, this article offers an insight into the somewhat disregarded topic of anticlastic bending by a short review of the published theories and a selection of representative numerical results.

The bending behaviour of thin stripes and leaf springs, in the presence of large deflections, is ruled by the so-called Bernoulli-Euler equation. The standard solution approach of this problem ('elastica') is represented by the non-linear finite-element analysis. In some special cases, closed-form solutions are available, which involve elliptic integrals and functions. In this article, an alternative method is presented based on the discretization of the deformed beam into circular-arc segments. The method is fast and simple to implement, and therefore suits well for the design and optimization of compliant kinematics.

The paper presents a comparison of six recently introduced multiaxial fatigue strength estimation criteria to four methods, the large-scope validation of which has already been published. The results obtained for each newer method are analyzed and discussed. From the newer methods, only the criterion by Böhme reaches an estimation quality similar to the best performing criteria. The validation was performed on the FatLim data sets, but the primary focus of the paper is set to analyzing the validation on a smaller AMSD25 data set derived from it. The comparison shows that the application of AMSD25 for validation practice allows users to reduce the number of evaluated test cases, while generally preserving the worst cases showing the weaknesses of various estimation methods.