Fundamental Study on Mehcanism of Deformation for Bonded Wood Materials

粘合木质材料变形机理的基础研究

基本信息

批准号：
08456084
负责人：
MIZUMACHI Hiroshi
金额：
$ 5.06万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

The three strain energy release rates, G_<IC>, G_<IIC>, and G_<IIIC>, of the adhesive joints corresponding to different deformation modes, namely, mode I,mode II and mode III,respectively, are their ability to resist crack propagation of solids in the adhesive layr. In this study, dependence of G_<IC>, G_<IIC> and G_<IIIC> on crack length were examined using the double-cantilever beam specimens by a compliance method, and the experimental conditions accorging to which G_<IC>, G_<IIC> and G_<IIIC> can be evaluated inrespective of the dimension of the specimen. The adhesive tensile strength and adhesive shear strength of the joints, where the same adhesives are used, were also measured. It was found that there is a positive correlation between the adhesive strength and square root of the strain eneygy release rete of the corresponding mode of deformation. However, thecorrelation coefficient was not necessarily high because a variety of commercially available adhesives were used in the first experiment. Then, in the next step of this study, some of the typical and well-defined adhesives were chosen, and again the strain energy release rates of the three different modes for the bonded wood specimens were evaluated, and at the same time the adhesive tensile strength and adhesive shear strength were measured. It was found that the rate-temperature superposition procedure can be applied to the strain energy release rates of the adhesive joints if they are measured as a function of both temperature and rates of deformation. Inaddition, there is a positive correlation between the adhesive shear strength and square root of the strain energy release rate of mode II in most cases, but the correlation between the adhesive tensile strength and square root of the strain energy release rate of mode I is expressed by a loop if the adhesive poiymer changes from the glassy state to the rubbery state within the temperature range of the experiments.

与不同变形模式相对应的粘合接头的三个应变能释放速率，G_ <ic>，G_ <iic>和G_ <iiiC>，分别是模式I，模式II和模式III，是它们抵抗粘合剂Layr中固体裂纹传播的能力。在这项研究中，使用双端梁梁样本通过合规方法检查了G_ <ic>，G_ <iic>和G_ <iiic>对裂纹长度的依赖性，并且可以评估G_ <iC>，g_ <iic>和G_ <iiic>的实验条件，可以评估该标志的减小。还测量了使用相同粘合剂的接缝的粘合性拉伸强度和粘合剪切强度。发现发现相应变形模式的应变释放的粘合强度与平方根之间存在正相关。但是，截止系数不一定很高，因为在第一个实验中使用了多种市售粘合剂。然后，在这项研究的下一步中，选择了一些典型且定义明确的粘合剂，并再次评估了粘合木材标本的三种不同模式的应变能释放速率，同时测量了粘合性拉伸强度和粘合性剪切强度。发现，如果粘合接头的应变能释放速率，则可以将速率 - 温度叠加程序应用于温度和变形速率的函数，并将其应用于粘合接头的应变能释放速率。不累及，在大多数情况下，模式II的应变能释放速率的粘合剪切强度与平方根之间存在正相关，但是如果粘合剂释放速率I的粘合性拉伸强度与粘合能释放速率的平方根之间的相关性是通过循环表达的，如果粘合剂的粘合剂在玻璃状状态下从玻璃状状态变化到橡胶状态内的橡胶状态，则在体验范围内的温度范围内。