Nonlinear oscillators with hardening and softening cubic Duffing nonlinearity are considered. Such classical conservative oscillators are known to have an amplitude-dependent period. In this work, we design oscillators with the Duffing-type restoring force but an amplitude-independent period. We present their Lagrangians, equations of motion, conservation laws, as well as solutions for motion.

Using cold working fastener holes is a simple life enhancement procedure that strengthens metallic components by retarding crack growth around a hole. In the present paper, the residual stress field that is induced by the hole expansion process is obtained based on different material models namely elastic perfect plastic, isotropic hardening and kinematic hardening using three-dimensional finit...

In the applications of parallel robots, kinematic calibration is required to eliminate the errors resulting from the manufacturing and assembly. In this paper, a new method for calibrating a parallel robot is proposed. An error model for kinematic calibration is constructed using differential geometry method. All leg length information and pose error are obtained based on measurement results co...

An elastic-viscoplastic constitutive material model is developed for the representation of creep response a 10%Cr steel under cyclic loading conditions. It has been shown that able to describe primary regeneration (PCR), i.e. incidence period high strain rate following stress reversal. The variant well-known Chaboche viscoplastic model, and employs bi-term power-law equation represent stress-re...