Dynamic Contact Behavior of a Golf Ball during an Oblique Impact

Abstract

The oblique impact between a golf ball and a rigid steel target was studied using a high-speed video camera. Video images recorded before and after the impact were used to determine the inbound velocity v i , rebound velocity v r , inbound angle q i , rebound angle q r , and the coefficient of restitution e. The results showed that q r and e decreased as v i increased. The maximum compression ratio ) c , contact time t c , average angular velocity 5, and tangential velocity v t , along the target were determined from images obtained during the impact. The images demonstrated that ) c increased with v i while t c decreased. In addition, 5 and v t increased almost linearly as v i increased. A rigid body model was used to estimate the final angular velocity 5* and tangential velocity 3 t * at the end of the impact; these results were then compared with experimental data.

Viscoelastic impact characterisation of solid sports balls used in the Irish sport of Hurling

“…Diameter compression and lateral expansion were in fact useful measures for characterising impact behaviour [33,34], yielding a true description of the change in shape of the ball. However, the deformation values of diameter compression and lateral expansion were dissociated from the measured impact force, thus being invalid for viscoelastic characterisation.…”

“…Many publications assume, either explicitly or implicitly, that diameter compression and COM displacement are equivalent [30][31][32], neglecting the effect (if any) of lateral expansion. The studies that have considered lateral expansion do not refer to COM displacement [33,34]. The publications that have constructed force-displacement curves used COM displacement values, although these graphs were not used to evaluate stiffness [27,32].…”

Friction Effect on Angular Velocity of a Golf Ball

“…ゴルフボールの衝撃特性に関する研究が種々の見地からなされている (1)～ (13) . 理論解析では，ボールとクラブとの 動特性を理解するために幾つかの方法が提案されている (1)～(4) ．一方，有限要素解析では，ボールをモデル化するこ とにより，クラブヘッド材や形状の最適設計が試みられている (5)～ (7) .…”

“…しかし解析結果の妥当性を検討するためには， 実験と比較することが重要である．これまでボールの衝撃力，接触時間，反発係数，回転速度などが計測されてい る (8)～ (11) . しかし衝撃時のボールの変形や回転計測は，技術的に容易ではなく，ほとんどなされていない． 筆者らは，高速ビデオカメラ (12) を用いて，ゴルフボールの衝撃計測を行ってきた．斜め衝突計測では，ボールの 接触時間，圧縮率，並進速度，回転速度を評価した (13) . また透明樹脂板との斜め衝突実験では，ボール接触面の時 間変化を計測し，摩擦効果について考察した (14) .…”

Dynamic Deformation Behavior of a Golf Ball during Normal Impact

“…In previous papers [16,17], we examined the dynamic contact behavior of a golf ball during an oblique impact with a rigid steel target and a PMMA target. The ball was launched horizontally at velocities between 10 and 60 m/s using an air gun, and struck the target at an oblique angle of 30°.…”