School of Mechanical Engineering, Dalian University of Technology, Linggong Road 2, 116024 Dalian, China; School of Mechanical and Power Engineering, Dalian Ocean University, Heishijiao Street 52, 116023 Dalian, China; R&D Center of Fisheries Equipment and Engineering of Liaoning Province, Heishijiao Street 52, 116023 Dalian, China.
School of Mechanical Engineering, Dalian University of Technology, Linggong Road 2, 116024 Dalian, China.
J Mech Behav Biomed Mater. 2018 Sep;85:209-217. doi: 10.1016/j.jmbbm.2018.06.012. Epub 2018 Jun 14.
In order to provide reference for the development of relevant dredging and processing machinery of the manila clam (Ruditapes philippinarum), the clam shell´s microstructure, phase composition, microhardness, nanoindentation hardness and elastic modulus were investigated, the quasi static compression and orthogonal compression tests of live clams were carried out as well. The shell consists of the outer, middle, and inner layer, which correspond with the composite prismatic structure, crossed-lamellar structure, and homogeneous structure, respectively. X-ray diffraction (XRD) results indicated that all the three layers are made up of pure aragonite phase, the outer layer of the shell displays greater intensity and more diffraction peaks than the middle and inner layer. The microhardness of the inner layer, ~ 3.00 GPa, is harder than the middle and outer layer. Both in the middle and outer layers, the microhardnesses of the vertical section perpendicular to the growth lines are obviously higher than that of the cross section parallel to the growth lines. The similar trend was observed in nanoindentation hardness (H) and elastic modulus (E), but the H/E ratios between three layers and two sections are close to 0.05. The quasi static compressive strengths of live clams with loading along the X (beak horizontal), Y (beak upward and umbo downward), and Z (beak vertical) orientations were tested, and the differences were identified. The lowest strength was found with loading orientation Z, the Weibull strength at 50% probabilities of fracture force is just 153 N. The results of the orthogonal compression tests demonstrated that the fracture force of clams varies from approximately 100 N to 400 N, the effect of the clams´ age on fracture force is more significant (p < 0.01) than loading orientation and loading speed. Therefore, the clams´ age and ultimate load of fracture should be taken into account during clam production mechanization, for the purpose of maintaining the clams´ integrity and survival prior to sale.
为了为菲律宾帘蛤（Ruditapes philippinarum）相关疏浚和加工机械的发展提供参考，研究了蛤壳的微观结构、相组成、显微硬度、纳米压痕硬度和弹性模量，还进行了活蛤的准静态压缩和正交压缩试验。壳由外层、中层和内层组成，分别对应于复合棱柱结构、交叉层状结构和均质结构。X 射线衍射（XRD）结果表明，所有三层均由纯方解石相组成，壳的外层显示出更大的强度和更多的衍射峰。内层的显微硬度约为 3.00 GPa，比中层和外层硬。在中层和外层中，垂直于生长线的垂直截面的显微硬度明显高于平行于生长线的横截面上的显微硬度。纳米压痕硬度（H）和弹性模量（E）也观察到了类似的趋势，但三层和两个截面之间的 H/E 比值接近 0.05。测试了活蛤在沿 X（喙水平）、Y（喙向上和脐向下）和 Z（喙垂直）方向加载时的准静态压缩强度，并确定了差异。在加载方向 Z 时发现强度最低，50%断裂力概率的威布尔强度仅为 153 N。正交压缩试验的结果表明，蛤的断裂力从大约 100 N 到 400 N 不等，蛤的年龄对断裂力的影响（p < 0.01）比加载方向和加载速度更为显著。因此，在蛤类生产机械化过程中，应考虑蛤类的年龄和断裂的极限载荷，以在销售前保持蛤类的完整性和生存能力。
