Bonding is known for its wide range of advantages over bolted joints when joining different materials together. However, the advantages e.g. of homogeneous load distribution can quickly be lost in case of overload. For this reason, the load occurring in the adhesive is reduced by constructive measures far below the yield stress of the adhesive, which leads to a conservative joint design. And to be on the safe side, a few “chicken rivets” are then placed again. This problem is particularly well known in aviation. Highly loaded components are structurally bonded by a combination of rivets and adhesive in order to underline the advantages of structural adhesive bonding with the safety of the well-known bolted joints. Known as fail-safe design, this concept is damage tolerant and more robust against manufacturing defects through a secured double load path. Especially when joining fiber-reinforced composites, bolts weaken the adherends of the joint and only contribute to load transfer when the brittle adhesive fails. With the help of Surface Toughening, a boltless technique for reducing stress concentrations and arresting cracks in adhesive bonded joints is available. This work describes the industrial application of this technique. Starting with coupon tests and a small scale demonstrator to ensure the compatibility with industrial manufacturing processes, such as infusion and prepreg manufacturing, a large scale demonstrator of a 2 m carbon fiber reinforced plastic (CFRP) - HTP leading edge with hybrid laminar flow control is manufactured by the industrial partner AERnnova. Verifying a simple and cost-effective application of the technology, Surface Toughening enables robust bonded joints with a minimum impact on today's process of adhesive bonding.

中文翻译：

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表面增韧——一种使用薄膜粘合剂提高纯粘合剂接头坚固性的工业方法

当将不同的材料连接在一起时，结合比螺栓连接具有广泛的优势而闻名。然而，在过载的情况下，例如均匀负载分配的优势可能很快丧失。因此，通过远低于粘合剂屈服应力的建设性措施降低了粘合剂中出现的载荷，这导致了保守的接头设计。为了安全起见，然后再次放置一些“鸡铆钉”。这个问题在航空领域尤其广为人知。高负荷部件通过铆钉和粘合剂的组合在结构上粘合，以强调结构粘合剂粘合的优点和众所周知的螺栓接头的安全性。被称为故障安全设计，这个概念是耐损坏的，通过安全的双负载路径更能抵抗制造缺陷。尤其是在连接纤维增强复合材料时，螺栓会削弱接头的被粘物，只有在脆性粘合剂失效时才有助于传递载荷。在表面增韧的帮助下，可以使用无螺栓技术来减少应力集中并阻止胶粘接头中的裂缝。这项工作描述了该技术的工业应用。从试样测试和小规模演示器开始，以确保与工业制造工艺（例如灌注和预浸料制造）的兼容性，2 m 碳纤维增强塑料 (CFRP) - HTP 前沿具有混合层流控制的大规模演示器是由工业合作伙伴 AERnnova 制造。