We measured fracture stiffness in 212 patients with tibial fractures treated by external fixation. In the first 117 patients (group 1) the decision to remove the fixator and allow independent weight-bearing was made on clinical grounds. In the other 95 patients (group 2) the frames were removed when the fracture stiffness had reached 15 Nm/degree. In group 1 there were eight refractures and in ...

Linear, friction-induced vibration and aeroelastic flutter problems are governed by second-order differential equations of motion in which the stiffness matrix and often damping matrix are asymmetric. Asymmetric systems are prone to unstable vibration (flutter) as a parameter reaches a critical value, when the real part of a pair of complex poles crosses the vertical imaginary axis of the s-pla...

In this paper, we develop an adaptive decentralized compliant control of robot manipulator. The robot manipulator is in contact with the environment and the contact force is normal to the contact plane. When the environment stiffness is given, an adaptive decentralized compliant controller is designed based on a Lyapunov based method such that both the force tracking error and the complementary...

The folded plate structure is a structural form that increases bending rigidity and strength by folding the plate. When plane bent in waves, in-plane stiffness wave orthogonal direction, but extremely decreases because meandering like spring direction. Since shell structures resist external forces mainly forces, it considered there an appropriate arrangement of corrugations according to flow wh...

Although stiffness and strength of lower limb bones have been investigated in the past, information is not complete. While the femur has been extensively investigated, little information is available about the strain distribution in the tibia, and the fibula has not been tested in vitro. This study aimed at improving the understanding of the biomechanics of lower limb bones by: (i) measuring th...

Hydroxyapatite (HAP) and fluorapatite (FAP) are essential components of dental enamel and bone. In this paper, we report a computational study of the elastic properties of HAP and FAP using ab initio and force field techniques. We have obtained the HAP and FAP elastic stiffness constants in hexagonal symmetry by fitting the Hooke law for both the energy-strain and stress-strain relations. Our a...

1. The stiffness (flexural rigidity) of some echinoderm sperm flagella was measured, using a flexible glass microneedle. 2. Values of 0-3-1 -5 x io a i N m were obtained for the stiffness of live flagella which were immobilized with COg-saturated sea water. 3. The immobilized live flagellum was uniform in stiffness along its entire length, except in a particular plane of imposed bending in whic...

INTRODUCTION Very often, woven fabrics are used as the reinforcement in advanced composite materials. Although the resulting inplane stiffness is lower than of their unidirectional counterparts, the excellent drapability of these materials eases the production of more general doubly curved components. In addition, the inherently low out-of-plane strength of these layered materials improves due ...

This research presents new data and reanalyzed information to refute the criticisms of our model of stiffness control during quiet standing. A re-review of their references to biomechanical research on muscle ankle stiffness confirmed muscle stiffness estimates of the ankle series elastic elements that agreed closely with our estimates. A new technique is presented that directly estimates the m...

Assumption of cutting disturbances in hard turning process (caused by variations in depth of cutting, high passive force Fp or small tool nose radius) could be confirmed with several indicators. These indicators can be monitored during turning process(forces, vibrations, sound, etc.) or after process has been finished (roughness, temperature, wear, etc). Variation of depth of cutting as well as...