High strain rate characteristics of wood arising from blast and impact loading

尺寸稳定性和耐火性能的提高以及工程木制品的广泛应用，如胶合板和交叉层压板(CLT)，促使人们重新对木基系统的概念产生兴趣，将其从典型的低层住宅建筑扩展到中高层应用。备受瞩目的建筑物(如大使馆、军方、高层办公楼、集会场所)经常面临蓄意攻击的风险，因此需要分析爆炸荷载。尽管它包含在加拿大的爆破设计标准中，但对木结构在爆炸荷载下的分析和设计提供的指导有限。高大的木材和木材混合结构的出现可能会增加使用木材建造高调结构的可能性。因此，工业界和研究界最近的努力都集中在建立木结构的爆炸反应上。目前对木材材料性能和破坏模式的了解仅限于在爆炸和冲击加载过程中经历的较低应变率范围。由于动态增长系数直接是应变率的函数，因此有必要研究在较高应变率下的特性和响应。本研究计划的目的是在系统水平上表征和改善木结构在爆炸和冲击载荷引起的高应变率(HSR)下的响应。这一长期目标将通过实验研究和开发分析模型初步确定木材构件的孤立行为来实现。*将在高铁下进行冲击试验，以表征木材材料在组件和系统水平上的特性。手指关节的高铁行为也将单独以及部分全面调查，以确定其对全球响应的影响。还将研究使用纤维增强聚合物(FRP)的新的加固和加固策略，以提供木构件固有的缺乏延性，以及开发有限元模型。该专业的研究生将获得对结构动力学、木结构设计以及与其项目相关的独特专业知识的广泛了解，从而使它们在研发部门、工程和咨询以及学术界具有广泛的市场。*了解木结构在冲击和爆炸载荷下的性能将导致在高铁获得以下方面的新知识：材料特性(动态增加系数)、响应限制、使用玻璃钢的加固和加固策略以及准确预测响应的数值和有限元模型。拟议的研究计划的结果将直接影响加拿大爆炸设计标准中当前的设计指南，并帮助工程人员进行分析和设计。

The improved dimensional stability and fire performance as well as broader availability of engineered wood products, such as glued-laminated timber (glulam) and cross-laminated timber (CLT), have contributed to a renewed interest in extending the concept of wood-based systems from the typical low-rise residential construction to mid- and high-rise applications. High-profile structures (e.g. embassies, military, office high-rise, gathering venue) often face a risk of a deliberate attack and thus are analyzed for blast loads. Despite its inclusion in the Canadian blast design standard, there is limited guidance provided for the analysis and design of wood structures to blast loading. The emergence of tall timber and timber-hybrid structures could increase the likelihood of a high-profile structure to be built using wood. As such, recent efforts from both the industry and research community have been directed towards establishing the blast response of wood structures. The current knowledge of the wood material properties and failure modes is limited to the lower strain rate range experienced during blast and impact loading. Since the dynamic increase factor is directly a function of the strain rate, there is a fundamental need in research to establish the properties and response at higher strain rates.******The objective of this research program is to characterize and improve the response of timber structures at a system level under high strain rates (HSR) arising from blast and impact loading. This long-term goal will be achieved by initially establishing the isolated behaviour of timber elements through experimental studies and development of analytical models. ******Impact tests characterizing the wood material properties at a component and system level under HSR will be conducted. The HSR behaviour of finger joints will also be investigated in isolation as well as part of full-scale elements to determine its effect on the global response. Novel retrofitting and strengthening strategies using fibre reinforced polymers (FRP) will also be investigated in order to provide ductility, which is inherently lacking in wood members, as well as to develop finite element models. Graduate students under this program will acquire a broad understanding of structural dynamics, design of timber structures, and a unique expertise related to their project, thus making them widely marketable in the research and development sector, engineering and consulting, and academia.******Understanding the performance of wood structures under impact and blast loading will result in new knowledge at HSR about: the material properties (dynamic increase factor), response limits, strengthening and retrofitting strategies using FRP, and numerical and finite element models to accurately predict the response. The outcomes from the proposed research program will directly influence current design guidelines in the Canadian blast design standard and assist engineering in their analysis and design.