| 摘要: | 本研究藉由壓縮試驗探討不同尺寸(小半徑、中半徑、大半徑，分別以S、M、L表示之)、球壁厚(薄壁、厚壁，分別以s、l表示之)，及堆積方式(隨機堆積Random、簡單立方SC、面心立方FCC，分別以RA、SC、FC表示之)對4605合金鋼空心球堆積結構壓縮性質之影響。
結果顯示，小半徑S (R=920)、厚球壁l (t=270)之空心球在面心立方FCC(堆積下(代號:S-l-FC)有最佳平台應力190.9 (MPa)；小半徑S (R=958)、薄球壁s (t=139)之空心球在面心立方FCC堆積下(代號:S-s-FC)有最佳單位能量吸收33.2 W (J/g)。
平台應力(σ_pl)及單位能量吸收(W)皆為: 面心立方FCC > 簡單立方SC > 隨機堆積Random，其餘尺寸及壁厚之空心球亦有相同趨勢。
面心立方FCC因為在變形時受到各方向球體的限制，導致降伏應力提高，並因此提升其平台應力(σ_pl)及單位能量吸收(W)，其壓縮時傾向分層坍塌，而簡單立方SC則是整體均勻變形。
平台應力(σ_pl)與t/R(球壁厚/半徑)成正比，單位能量吸收(W (J/g))隨著t/R值提高而上升並在到達最高點後下降。在隨機堆積Random中當t/R=0.144時有最佳之單位能量吸收26.4 J/g，簡單立方SC及面心立方FCC中亦有相同趨勢。
隨機堆積Random及面心立方FCC存在空位(缺陷)，單位能量吸收受球體半徑影響而下降，單顆空心球因無任何空位(缺陷)，因此具有比堆積結構更高的平台應力MPa及單位能量吸收W (J/g)。
;This study investigates the compressive properties of 4605 alloy steel hollow sphere packing structures by conducting compression tests on different sphere sizes (small radius, medium radius, large radius, denoted as S, M, and L, respectively), sphere wall thicknesses (thin wall, thick wall, denoted as s and l, respectively), and packing arrangements (random packing, simple cubic SC, face-centered cubic FCC, denoted as RA, SC, and FC, respectively).
The results show that hollow spheres with a small radius (S, R=920) and thick walls (l, t=270) in a face-centered cubic FCC packing arrangement (denoted as S-l-FC) exhibit the best plateau stress of 190.9 MPa. Hollow spheres with a small radius (S, R=958) and thin walls (s, t=139) in a face-centered cubic FCC packing arrangement (denoted as S-s-FC) exhibit the best specific energy absorption of 33.2 W (J/g). Both plateau stress (σ_pl) and specific energy absorption (W) follow the trend: face-centered cubic FCC > simple cubic SC > random packing RA, with similar trends observed for other sphere sizes and wall thicknesses.
The face-centered cubic FCC arrangement, due to the restriction from spheres in all directions during deformation, leads to an increase in yield stress, thereby enhancing both the plateau stress (σ_pl) and specific energy absorption (W). During compression, the FCC arrangement tends to collapse in layers, while the simple cubic SC arrangement deforms uniformly overall.
Plateau stress (σ_pl) is directly proportional to t/R, and specific energy absorption (W (J/g)) increases with the t/R ratio until it reaches a peak, then decreases. In random packing RA, the optimal specific energy absorption of 26.4 J/g is achieved when t/R=0.144, with similar trends observed in simple cubic SC and face-centered cubic FCC arrangements.
Random packing RA and face-centered cubic FCC contain vacancies (defects), leading to a decrease in specific energy absorption influenced by sphere radius. A single hollow sphere, having no vacancies (defects), exhibits higher plateau stress (MPa) and specific energy absorption (W (J/g)) compared to packed structures. |
