Measurement of rolling shear modulus of Cross Laminated Timber: Exploratory study using downscaled specimens under variable span bending tests
The purpose of this study was to measure the rolling shear modulus of Cross Laminated Timber (CLT), which was achieved by conducting 3-point bending tests with variable span using downscaled sandwich specimens. Two types of sandwich specimens were employed: steel-wood-steel (SWS) and wood-wood-wood (WWW). Experimental results from SWS specimens were verified with those predicted from WWW ones through the shear analogy method. Effects of span-to-depth ratio (l/h) and growth ring orientation on rolling shear modulus (GRT) were also examined. It was found that the average deflection of WWW specimens tested at l/h of 6.5 could be well predicted using the shear analogy method based on true elasticity of modulus (Em) and GRT of the cross layer measured using SWS specimens under variable span tests. The results also showed that the cross layer of `in-between' growth ring orientation could gain the higher rolling shear modulus than that of flat sawn or quarter sawn one.
An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method
Summary Shearing is an essential deformation in the treatment of mechanical pulp fibers into a papermaking pulp. Knowledge of the contribution of shear to the fiber treatment during processing can be obtained by measurements on fibers in the form of wood. In this work, an attempt was made to use the Iosipescu method for testing wood in rolling shear. Despite the small size of the shear region of interest between notches made in the wood, the results and their dispersion in both the elastic and inelastic ranges were in accordance with previous results found using other testing methods. The stress-strain relationship was analysed in relation to the specimen's density profiles in the region of interest. Differences in density explained up to 50% of the inter-specimen variability in the shear modulus and in the inelastic behavior. Failure occurred outside the shearing zone in a large number of specimens. Thus the configuration chosen was not adapted to provide for the strength of wood in rolling shear. This behavior limited the amplitude of the strain that could be reached between the notches.
Fluid to liquid membrane energy exchanger for simultaneous liquid desiccant regeneration and desalination applications–Theoretical and experimental analyses
Abstract In this paper, a thermal model developed for assessing the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator is presented. The model was validated with the experimental data and found accurate. Using the experimental inlet conditions reported in the literature for the structured packing chamber, the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator was theoretically predicted choosing water and air as working fluids and Lithium Chloride as a liquid desiccant. Further, studied the influence of inlet parameters such as working fluid and desiccant inlet temperature’s, hot liquid desiccant to cold working fluid ratio and desiccant concentration on vapour absorption rate. From this analysis, it is observed that membrane based liquid desiccant regenerator using water as a working fluid is best suitable for converting the weak desiccant into strong desiccant and for generating the pure water simultaneously (co-generation process). An experimental investigation was carried out for assessing the energy exchange process across the membrane based liquid desiccant regenerator using water as a working fluid. From the experimental analysis, it was found that desiccant temperature has a significant impact on the energy exchange process. The pressure drop across the membrane based liquid desiccant regenerator was also measured at different desiccant flow rates and concentration.