Raw material accounts for a large proportion (approximately 75 percent) of a sawmill’s operating costs. However, about 15 percent of raw material ends up as low valued sawdust and planer shavings due to inaccurate cutting. Sizable financial benefits can be realized through maximizing conversion of raw material into valuable solid wood. Advanced process control in a sawmill can help achieve straighter cuts closer to final product dimensions and reduce loss of valuable raw material. A novel and practical method for enhanced process control in a sawmill is presented. A laser arrangement consisting of industrial point and line scanners is used to obtain a surface profile of the entire (two-dimensional) top and bottom surfaces of a lumber board. Each surface profile is independent of the other and free of data contamination caused by relative motions between the measured surface and sensors. Point scanners and line scanners simultaneously record 1-D and 2-D height data, respectively, along the length of the board. One-dimensional height data are used to identify relative motions through a mathematical technique based on linear inverse theory. Subtracting relative motion information from raw line scanner data provides an accurate 2-D surface profile. A second line scanner placed below the board can be used to obtain a separate 2-D profile of the bottom lumber surface. Separate-sided profiling is advantageous because typically a different saw or machine mills each side of a board. Thus, knowing the surface profile of each side of a board is crucial not only in diagnosing a deficiency in the milling process but also in determining the location of this deficiency. Results demonstrate that two-dimensional surface profiling can identify common surface defects such as step, washboard and knot tear-out with an accuracy of 0.3mm. Reproduction of each surface is rapid (approximately 0.2 seconds) and stable.

Raw material accounts for a large proportion (approximately 75 percent) of a sawmill’s operating costs. However, about 15 percent of raw material ends up as low valued sawdust and planer shavings due to inaccurate cutting. Sizable financial benefits can be realized through maximizing conversion of raw material into valuable solid wood. Advanced process control in a sawmill can help achieve straighter cuts closer to final product dimensions and reduce loss of valuable raw material. A novel and practical method for enhanced process control in a sawmill is presented. A laser arrangement consisting of industrial point and line scanners is used to obtain a surface profile of the entire (two-dimensional) top and bottom surfaces of a lumber board. Each surface profile is independent of the other and free of data contamination caused by relative motions between the measured surface and sensors. Point scanners and line scanners simultaneously record 1-D and 2-D height data, respectively, along the length of the board. One-dimensional height data are used to identify relative motions through a mathematical technique based on linear inverse theory. Subtracting relative motion information from raw line scanner data provides an accurate 2-D surface profile. A second line scanner placed below the board can be used to obtain a separate 2-D profile of the bottom lumber surface. Separate-sided profiling is advantageous because typically a different saw or machine mills each side of a board. Thus, knowing the surface profile of each side of a board is crucial not only in diagnosing a deficiency in the milling process but also in determining the location of this deficiency. Results demonstrate that two-dimensional surface profiling can identify common surface defects such as step, washboard and knot tear-out with an accuracy of 0.3mm. Reproduction of each surface is rapid (approximately 0.2 seconds) and stable.

Raw material accounts for a large proportion (approximately 75 percent) of a sawmill’s operating costs. However, about 15 percent of raw material ends up as low valued sawdust and planer shavings due to inaccurate cutting. Sizable financial benefits can be realized through maximizing conversion of raw material into valuable solid wood. Advanced process control in a sawmill can help achieve straighter cuts closer to final product dimensions and reduce loss of valuable raw material. A novel and practical method for enhanced process control in a sawmill is presented. A laser arrangement consisting of industrial point and line scanners is used to obtain a surface profile of the entire (two-dimensional) top and bottom surfaces of a lumber board. Each surface profile is independent of the other and free of data contamination caused by relative motions between the measured surface and sensors. Point scanners and line scanners simultaneously record 1-D and 2-D height data, respectively, along the length of the board. One-dimensional height data are used to identify relative motions through a mathematical technique based on linear inverse theory. Subtracting relative motion information from raw line scanner data provides an accurate 2-D surface profile. A second line scanner placed below the board can be used to obtain a separate 2-D profile of the bottom lumber surface. Separate-sided profiling is advantageous because typically a different saw or machine mills each side of a board. Thus, knowing the surface profile of each side of a board is crucial not only in diagnosing a deficiency in the milling process but also in determining the location of this deficiency. Results demonstrate that two-dimensional surface profiling can identify common surface defects such as step, washboard and knot tear-out with an accuracy of 0.3mm. Reproduction of each surface is rapid (approximately 0.2 seconds) and stable. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Rail corrugation is a periodic wear pattern that develops on the wheel and rail contacting surfaces in railway systems. It is a commonly observed phenomenon worldwide and is a serious problem because it causes degradation of the track and its components and is a significant source of noise. Currently the only reliable method of ameliorating the negative effects of rail corrugation is to periodically regrind the rail surface to a smooth profile, at great expense to the railway operator. It is therefore of interest to investigate other possible control strategies to reduce corrugation growth through an understanding of the mechanism of corrugation formation. This thesis presents an investigation into the effect of speed variation on the corrugation formation mechanism. The research presented is intended to highlight the significant role that speed variation has on corrugation formation via a disruption of the feedback mechanism which leads to corrugation growth over successive train passages. This discovery motivates the investigation the feasibility of altered speed variation as a novel corrugation control method, due to the large effect that the variance of train speed has on corrugation growth rates. The effect of variable pass speed on corrugation formation has been investigated in this thesis through the use of efficient models of corrugation formation in straight track and cornering conditions. These models are simple enough to readily perform corrugation control studies without neglecting any relevant physics, obscuring the corrugation formation mechanism with overly detailed modelling or imposing a significant computational burden on performing control studies. These novel models have been outlined and their predictions elucidated in detail. A theoretical investigation into the effect of speed variation in the presence of a resonance free mechanism for corrugation growth via a contact filter has been performed and shown to only be important when the dynamic wavelength of formation approaches the size of the contact patch. The results of these corrugation models have been validated via test rig and field experiments. An investigation of the effectiveness of speed variation as a corrugation growth control measure has also been investigated via test rig experiments. The results of this thesis have formed the basis of an industry supported field trail of this technique for corrugation mitigation that is currently in progress.

Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess high stiffness and strength properties, the stiffness of composite laminates may be maximized by changing the geometry. By adding corrugations, the flexural stiffness is increased in one direction compared to the stiffness of a flat part with the same amount of material. Thus, stiffness increases without a change in weight. The primary goal of this research was to investigate the stiffness characteristics of corrugated composite laminates under tensile and flexural load. The chosen corrugation geometry for investigation was a trapezoid. To observe the effects of corrugations, both flat and corrugated coupons were tested experimentally with the same procedures. Stiffness was calculated experimentally, analytically, and numerically in both directions. In this study, the longitudinal direction was defined as perpendicular to the corrugations and transverse direction was defined as the direction along the corrugations. The effects on stiffnesses of corrugated and flat composites were measured by comparing changes to the stiffness ratios in tension and bending. The stiffness ratio is the ratio of longitudinal stiffness to transverse stiffness. The secondary aim of this research was to compare the corrugation effects on FG weave and cross-ply CF. This was interesting to observe the difference in corrugation effects on different composite materials. The FG laminates were manufactured from four plies of pre-impregnated Cytec MXB 7701/7781. The CF laminate consisted of five plies of pre-impregnated unidirectional Tencate TC250/M46J. The layup orientation of the CF laminate had alternating 0◦ and 90◦ plies, where the 0 ◦ plies were in the transverse direction. Plies were directly laid on a flat plate and aluminum mold for flat and corrugated specimens, respectively. All flat and corrugated composites were cured in an autoclave under respective recommended cure cycles for each material. The tension and three-point bend tests were conducted on an Instron 8800 where the load was applied at a rate of 0.05 inches per minute. The tensile ultimate load was the same between corrugated and flat specimens in the longitudinal direction. Meanwhile, the tensile ultimate load was greatly reduced for corrugated specimens in the transverse direction when compared to the flat specimens. Thus, corrugations had a larger impact in the transverse direction under tensile load for both materials. By corrugating the composite layups, the ratio of stiffness in the longitudinal to extensional direction increases. For FG test coupons, the extensional stiffness ratio was increased from 1.0 to 49.3 due to corrugations. The flexural stiffness ratio was increased from 0.3 to 187.1 in corrugated FG coupons. For CF test coupons, the extensional stiffness ratio increased from 0.7 to 61.3. The flexural stiffness ratio of CF test coupons increased from 0.3 to 81.4. Corrugations had a greater effect on the cross-ply CF for both extensional and flexural stiffnesses.

<p><strong>In this study, detailed numerical analysis is carried out to investigate the effects of strain hardening on necking improvement by using finite element package ABAQUS. In addition, the response of laminated composite in necking, pure bending and hydroforming is also examined. It is concluded that architectured structure, especially corrugated reinforcement is an efficient method to significantly improve necking strain.</strong></p> <p><strong>The necking strain is proportional to the strain hardening rate and volume fraction of the cladding material for laminated composite. In pure bending process, the residual stress distribution varies according to different material composition. The extent of springback is linearly related to the bending moment.</strong></p> <p><strong>After the unloading in hydroforming process, the volume change of the specimen is linearly related to the fluid pressure while the slope of the linear function is independent to the material composition.</strong></p> <p><strong>Under 2D plane strain tension, corrugated reinforcement is able to provide high strain hardening rate at large strain, and hence significantly improve necking strain of the composite. Small scale corrugation is superior to large scale ones in both necking strain and strength improvement. An optimal scale exists for highest necking strain and strength while further decrease of scale deteriorates the tensile response.</strong></p> <p><strong>The anisotropic improvement of necking strain by 2D corrugation can be extended to other directions by 3D cone reinforcement. Under plane strain condition, the cone reinforcement is superior to the flat reinforcement in necking strain while remaining comparable strength.</strong> <h1></h1></p> / Master of Applied Science (MASc)

Composite structures have demonstrated great potential to improve mechanical performance in various applications, including ballistics protection. This study demonstrates that the integration of geometrically optimized composites into core-face sheet assemblies provide great impact resistance. The research investigated the performance of two composite manufacturing methods under low-velocity impact through residual strength and damage comparisons. Corrugated core composites were produced with traditional manufacturing methods, namely compression molding, using twelve stacking sequences. These stacking sequences were chosen to represent four laminate groups, where a unique fiber orientation scheme was employed across three laminate thicknesses (6, 8, and 12 layers). In contrast, honeycomb and auxetic cell cores were produced using continuous fiber-reinforced 3D printing. To maintain consistency, both the corrugated cores and the advanced cell cores were produced with para-aramid fibers, though the matrix differed between the two manufacturing methods. The cores were subjected to a consistent drop-weight impact event under various impact cases where the makeup of the assembly differed. The findings of this testing showed that external damage decreased as layer count increased for the laminates and that the addition of a silica damping material significantly improved post-impact, out-of-plane compressive response. In addition, testing proved that the cross-ply, longitudinally dominant laminates & the honeycomb printed composite exhibit exceptional out-of-plane compressive strength prior to and after impact. The cross-ply core retained 58.0% of its pre-impact stiffness & 68.3% of its pre-impact strength while the honeycomb core retained 88.0% of its pre-impact stiffness and did not fail under the maximum compressive load. Aside from impact testing, theoretical and numerical analyses were performed. Classic Laminate Plate Theory was employed to predict laminate engineering constants, while finite element models were created to simulate the in-plane response of the cores. The theoretical approach roughly approximated the longitudinal modulus, though the error was significant. In contrast, the finite element models developed closely mirrored experimental tensile behavior, with peak stress predicted within 5% of experimental results. The compressive response was also well captured by the model, though the displacement to buckling onset was underpredicted by 38.0%.

In practice, baffle blocks and sills are commonly being used to stabilize the location of a hydraulic jump and shorten the length of a stilling basin. On the other hand, gravels, corrugations and rectangular prismatic roughnesses which cover the entire length of the basin or placed in a staggered manner may be an alternative. The objective of this study is to determine the effects of these roughness elements on the characteristics of hydraulic jumps such as conjugate depth, jump length and energy dissipation using experimental data collected from the previous studies. The investigations show that the roughness elements have positive effects on the characteristics of hydraulic jumps. The tailwater depth reduction compared to classical jump is 2-10%. The length of the jump is reduced about by 30-50% by prismatic roughness elements, 40% by corrugations, and 30% by gravels. The roughness elements induce 3-15% more energy dissipation than that of classical jump. Therefore, these types of bed roughness elements should be considered as an effective alternative of accessory devices such as baffle blocks and sills.

Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.

Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.