Limpets are molluscs which have a conical shell that is well adapted to resist fracture by impact from projectiles such as rocks during storms. We hypothesised that the impact strength of the shell varies depending where the animal is located, reflecting the relative risk of high-energy impact. We quantified shell impact strength for the species Patella vulgata using a normalised energy. Limpets located in exposed places on open rock surfaces were found to be more than twice as strong as those living constantly underwater (7.34 MJ/m 4.6 v 3.48 MJ/m 4.6 ). This difference was discussed using a theoretical model based on the physics of projectiles moving through fluids. Limpets located in rocky crevices had an intermediate impact strength (5.43 MJ/m 4.6 ), attributed to the reduced probability of impact in these locations. Differences in impact strength were found to be linked to two geometric parameters: apex thickness and the ratio of apex height to rim diameter. Combining the present results with data from previous work, we developed a theoretical model which was able to predict impact strength accurately as a function of rim diameter, apex height and apex thickness. These results demonstrate the considerable plasticity of form, which this species is capable of, helping to explain why it is so abundant. The findings may be valuable in the biomimetic development of lightweight impact resistant structures.

中文翻译：

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帽贝壳的抗冲击性：局部适应性研究

帽贝是软体动物，具有圆锥形外壳，非常适合在风暴期间抵抗岩石等抛射物的撞击而破裂。我们假设外壳的冲击强度因动物所在的位置而异，反映了高能量冲击的相对风险。我们使用归一化能量量化了 Patella vulgata 物种的外壳冲击强度。发现位于开放岩石表面暴露位置的帽贝比长期生活在水下的帽贝强两倍多 (7.34 MJ/m 4.6 v 3.48 MJ/m 4.6 )。使用基于射弹穿过流体的物理学的理论模型讨论了这种差异。位于岩石裂缝中的帽贝具有中等的冲击强度 (5.43 MJ/m 4.6 )，这归因于在这些位置的冲击概率降低。发现冲击强度的差异与两个几何参数有关：顶点厚度和顶点高度与轮辋直径的比率。将当前结果与先前工作的数据相结合，我们开发了一个理论模型，该模型能够准确预测作为轮辋直径、顶点高度和顶点厚度函数的冲击强度。这些结果表明该物种具有相当大的形式可塑性，有助于解释为什么它如此丰富。这些发现可能对轻型抗冲击结构的仿生开发很有价值。我们开发了一个理论模型，该模型能够准确预测作为轮辋直径、顶点高度和顶点厚度函数的冲击强度。这些结果表明该物种具有相当大的形式可塑性，有助于解释为什么它如此丰富。这些发现可能对轻型抗冲击结构的仿生开发很有价值。我们开发了一个理论模型，该模型能够准确预测作为轮辋直径、顶点高度和顶点厚度函数的冲击强度。这些结果表明该物种具有相当大的形式可塑性，有助于解释为什么它如此丰富。这些发现可能对轻型抗冲击结构的仿生开发很有价值。