Research On Microwave Of Wood Drying Strain

In this study, elm as test materials, with Sections on microwave treated specimens to study the stress and strain analysis of different microwave power and microwave treatment time on the impact of stress and strain, the strain components dry timber thinning, in drying process, the total strain from the free shrinkage strain, instantaneous elastic strain, viscoelastic strain and mechanical strain adsorption, namely microwave treatment of the different circumstances of each strain of drying, as well as the impact of stress relaxation, the following Conclusion:(1)Free shrinkage strain in the test material to water contents of the following will produce FSP. Throughout the drying process, the surface of the free shrinkage strain is the largest, the more close to the core layer the smaller the free shrinkage strain. Carried out with the conventional drying process, moisture content decreased gradually, the free shrinkage strain increased, but the change in the trend slowing, the overall upward trend.(2) Instantaneous elastic strain in the microwave after the test specimens shall have reached the maximum levels, the surface of specimens tensile elastic strain in the extreme state of internal layers in a state of extreme compression elastic strain state. With the continuation of conventional drying, the surface of the tensile elastic strain decreases gradually compressed by the tensile elastic strain to elastic strain development, and in the dry end of the maximum compression elastic strain; elastic strain within the layers of compression decreases by the compression of elastic strain to the tensile elastic strain development.(3)The evolution of viscoelastic strain and the instantaneous elastic strain were similar and that wood is beginning to surface tensile elastic strain, with the drying process progresses, the gradual transition to the compression elastic strain; timber is generated within the layers start compression elastic strain, with the drying process progresses, the gradual transition to the tensile elastic strain and viscoelastic strain and elastic strain in the same order of magnitude.(4)Mechanical strain on any water absorption rate will have, throughout the drying process, surface adsorption of strain for the tensile state machine, core machinery adsorption strain compression state, and showing a first increased and then decreased.(5) Specimens after microwave treatment, the levels of the stress relaxation process can be divided into the initial phase of rapid reduction of the stress process and the long slow relaxation process similar to the flat. Specimens by the same microwave power, microwave time, the greater the shorter the initial stress, the greater the residual stress; by the same microwave time to deal with, the smaller the initial stress of the larger microwave power, the greater the residual stress.