Abstract Bounds to the overall stiffness of a composite are well-known within classical theory elasticity. They based on positive-definiteness local stiffness. A transfer prestressed state is not trivial. We may study incremental that connects nominal stress rate with velocity gradient. But when there mainly compressive stresses, then can only be secured if this replaced by pseudo-stiffness. It...

An approach to analyzing structures by using beam elements is developed with adaptive displacement interpolation functions. First, the element stiffness matrix and equivalent nodal loads are derived on the basis of the equilibrium between nodal forces and section forces rather than the compatibility between nodal deformations and section deformations, which avoids discretization errors caused b...

This paper deals with a class of parallel mechanisms, called Gough-Stewart platforms. For these mechanisms, pre-loaded by driving forces, the stiffness matrix is derived and its basic properties are established. It is shown when the stiffness matrix becomes asymmetric, how the parametric imbalance may influence the system stability, and how the center of stiffness depends on the force pre-loadi...

This paper describes a stiffness analysis of a 6-RSS parallel manipulator by using matrix structural analysis. The stiffness analysis is based on standard concepts of static elastic deformations. The formulation has been implemented in order to obtain the stiffness matrix that can be numerically computed by defining a suitable model of the manipulator, which takes into account the stiffness pro...

This paper studied the stiffness model and characteristics of a planar 3-RPS PM with 3-DOF. The 6 × 6 form stiffness matrix of the planar 3-RPS PM is derived with both active and constrained wrenches considered. To characteristic the stiffness of the planer 3-RPS PM, two decomposition methods including the eigenscrew decomposition and the principle axes decomposition are applied to the stiffnes...

This paper investigates the synthesis of a spatial stiffness matrix using simple line springs. A new algorithm is developed, which enables the selection of constituent springs based on their positions and directions. The constraining space of the line springs is then investigated. It is shown that an isotropic stiffness matrix, in general, can be split into the sum of two rank-3 stiffness matri...

One step on the way to approach human performance in robotics is to provide joint torque sensing and control for better interaction capabilities with the environment, and a large number of actuated degrees of freedom (DOF) for improved versatility. However, the increasing complexity also raises the question of how to resolve the kinematic redundancy which is a direct consequence of the large nu...

Increased stromal stiffness is associated with hepatocellular carcinoma (HCC) development and progression. However, the molecular mechanism by which matrix stiffness stimuli modulate HCC progress is largely unknown. In this study, we explored whether matrix stiffness-mediated effects on osteopontin (OPN) expression occur in HCC cells. We used a previously reported in vitro culture system with t...

Breast epithelial cells sense the stiffness of the extracellular matrix through Rho-mediated contractility. In turn, matrix stiffness regulates RhoA activity. However, the upstream signaling mechanisms are poorly defined. Here we demonstrate that the Rho exchange factor GEF-H1 mediates RhoA activation in response to extracellular matrix stiffness. We demonstrate the novel finding that microtubu...

Abstract. A novel approach for free vibration analysis of train body structures is introduced by using the Carrera Unified Formulation (CUF) and Dynamic Stiffness Method (DSM). Higher-order kinematic fields are developed Formulation, which allows straightforward implementation any-order theory without need ad hoc formulations, in case beam theories. In particular, parallel axis theorem on basis...