Introduction Patellofemoral (PF) pain syndrome is one of the most common problems of the knee. Typical symptoms are anterior knee pain, exacerbated by activities such as stair descent, prolonged sitting and squatting. Patellar maltracking is generally accepted as a leading cause of PF pain (PFP). However, effective intervention has been hampered because the mechanical factors related to PFP are...

This paper exploits the concept of stabilized finite element methods to formulate stable mixed stress/displacement and strain/displacement finite elements for the solution of nonlinear solid mechanics problems. The different assumptions and approximations used to derive the methods are exposed. The proposed procedure is very general, applicable to 2D and 3D problems and independent of the const...

Background With 4D MR flow imaging, eccentric flow has been reported in patients with bicuspid aortic valve (BAV) and investigated as a risk factor for ascending aortic (AsAo) aneurysms [1]. We have demonstrated that a new parameter, normalized displacement, quantifies the degree of flow eccentricity in the AsAo [2]. However, it only offers information on a single location in the AsAo. The aim ...

Functionally defined neuromuscular structures, or modules (e.g., agonist-antagonist pairings), may be decoupled when elicited by a startling auditory stimulus (SAS), revealing possible lower-level functional units. The current study examines lip kinematics in SAS-induced responses and uses a 3D FEM biomechanical model to simulate the temporal interaction between facial muscles used in speech. R...

We investigate low-energy deformations of a thin elastic sheet subject to a displacement boundary condition consistent with a conical deformation. Under the assumption that the displacement near the sheet’s center is of order h| logh|, where h ! 1 is the thickness of the sheet, we establish matching upper and lower bounds of order h2| logh| for the minimum elastic energy per unit thickness, wit...

A new technique for computation structural instability points using the finite element method is presented. The approach is based on the estimation of critical displacement pattern by writing an approximation of the tangent stiffness singularity condition at the instability point. The critical load is subsequently computed by using a secant load-displacement relationship. Details of this proced...

Non-destructive 3D micro-computed tomography (microCT) based finite element (microFE) models are used to estimate bone mechanical properties at tissue level. However, their validation remains challenging. Recent improvements in the quantification of displacements in bone tissue biopsies subjected to staged compression, using refined Digital Volume Correlation (DVC) techniques, now provide a ful...

To build a patient specific respiratory motion model with a low dose, a novel method was proposed that uses a limited number of 3D lung CT volumes with an external respiratory signal. 4D lung CT volumes were acquired for patients with in vitro labeling on the upper abdominal surface. Meanwhile, 3D coordinates of in vitro labeling were measured as external respiratory signals. A sequential corre...

The work performance of stereo digital image correlation (stereo-DIC) technologies, especially the operating accuracy and reliability in field applications, is not fully understood. In this study, key technologies remote 3D displacement sensing civil structures based on stereo-DIC have been proposed. An algorithm incorporated improving matching control points. adaptive extrinsic parameter calib...