Experimental Research On Mechanical Properties Of Larch Glued Laminated Columns

Appropriate domestic fast-growing timber has not been found accordingly to support the development of modern timber structure. Thus, it is essential to consider mechanic properties of timber into research to develop engineering wood. In this thesis larch, one of the most widely plant in China, is used to manufacture glued laminated (glulam) members. Experiments on compresure in both rift grain and cross grain of these glulam conlumns are conducted, then the effects of different load types on colulmns are discussed which mainly include compressive property and ductility property. Expressions of stress distribution in different directions are also developed. Moreover, ANSYS is applied to model and anlyse stress distribution and strain distribution. All is expected to develop references for structural design and application in timber engineering.A brief description of the main work in this thesis is presented here.1. Stress-strain gauge and stress wave have been considered as the techniques to respectively measure static and dynamic elastic modules of larch glulam effectively. It can be found that the value of static elastic module is1.23times of dynamic elastic module.2. The comparative performance of glulam conlumns subjected rift grain compresure and cross grain compresure is studied. It is obeseved that they both belong to plastic failure form. Cross grain experiences a longer plastic failure period than rift grain does, the plastic failure period of cross grain is increase mildly while that of rift garin decrease dramatically. Also, ultimate stress of rift grain is higer than that of cross grain. Additionally, the good ductility property of glulam conlumns can be achieved by conducting a multi-stage cyclic loading experiment, but the ultimate stress is lower than that of axial compresure in rift grain.3. The constitutive expressions of glulam conlumns are determined under anxial compresure. That is to say, transversal stress distribution expressions and the relationship between transversal strain and axial compresure are analyzed as glulam can be described as the transversely isotropic material. It turns out that transversal stress is the quadratic function of the length of cross-section, and transversal strain grows cubically of a function of axial compresure.4. Finite element analysis (ANSYS) is finally performed so as to check experimental and theorital conclusions. The numerical simulation results not only agree with the experimental data in terms of both stress-strain curves, but also expressions of stress and strain distribution...