18,335 research outputs found
A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties
It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly, determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (Mean ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between-driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60 – 67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties
Estudio de la fisuración de paneles sándwich de yeso laminado y alma de lana de roca = Study of the cracking of sandwich panels of plasterboard and rockwool
Este artÃculo presenta el estudio de la rotura de paneles
sándwich de yeso laminado y lana de roca bajo solicitaciones
de flexo-tracción dentro de su plano. Estos paneles se
emplean para conformar tabiques interiores de edificación
y con frecuencia se fisuran por flechas excesivas en los
forjados. Actualmente no hay modelos de cálculo fiables ni
datos experimentales que permitan estudiar este problema.
Este trabajo presenta los resultados de una campaña
experimental encaminada a caracterizar el comportamiento
en rotura de los paneles sándwich y de sus componentes
individuales. Además, se presenta un modelo cohesivo
con fisura embebida que permite simular el comportamiento
en rotura del panel sándwich conjunto. Por último
se presentan los resultados de los ensayos de fractura en
modo mixto (tracción/cortante) de paneles comerciales y
se reproduce su comportamiento con el modelo cohesivo
propuesto, obteniéndose un buen ajuste. This paper presents the study of plasterboard and rockwool sandwich panels cracking under flexural loading. These panels are usually used to perform interior partition walls and they frequently show cracking pathology due to excessive deflexion of the slabs. There are currently no reliable simulation models and experimental data for the study of this problem. This paper presents the results of an experimental campaign aimed to characterize the fracture behaviour of sandwich panels and their individual
components. In addition, the paper presents a cohesive
model with embedded crack to simulate the fracture behaviour
of the panel. Finally we present the results of tests
for mixed mode fracture (tensile / shear) commercial panels
and their behaviour is reproduced with the cohesive
model proposed, yielding a good fit
- …