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Effects Of Temperature And Creep On The Clamp Up Load In Hybrid Metal To Composite Bolted Joints
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Book Synopsis Effects of Temperature and Creep on the Clamp-up Load in Hybrid Metal to Composite Bolted Joints by : Mauricio Fernandez
Download or read book Effects of Temperature and Creep on the Clamp-up Load in Hybrid Metal to Composite Bolted Joints written by Mauricio Fernandez and published by . This book was released on 2008 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effect of Temperature and Viscoelastic Creep on the Clamp-Up Load in Hybrid Composite/Metal Bolted Joints by :
Download or read book Effect of Temperature and Viscoelastic Creep on the Clamp-Up Load in Hybrid Composite/Metal Bolted Joints written by and published by . This book was released on 2009 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid composite to metal bolted joints are the focus of much research due the inherent advantages that they present. In particular, they are very attractive to designers and engineers alike due to their simplicity and ease of disassembly. However, hybrid connections are particularly susceptible to metal fatigue, stress relaxation primarily due to viscoelastic creep of the composite, thermal effects due to coefficient of thermal expansion mismatch, galvanic corrosion between the dissimilar constituents of the joint and moisture absorption causing differential strain between the metal and composite. The study presented in this report focuses in an investigation of the effects of temperature and primary creep in hybrid metal to composite bolted connections. The study's relevance stems from the desire to apply this technology to naval applications, where watertight integrity must be maintained. It was then decided to examine this type of connection at the subcomponent level. Therefore, EGlass/vinyl ester plates!4" thick were bolted to aluminum and steel plates of the same thickness with instrumented steel bolts to determine the primary stress relaxation response. Special attention was placed on the effects of temperature change on the stress relaxation that hybrid connections are particularly susceptible from. A model was developed with the sole purpose of integrating the existing coefficient of thermal expansion mismatch between all the joint parts in the scheme of analysis. Experiments were carried out to obtain the CTE of the composite material used in the hybrid connection tests, and a computer program, GASmooth, was specifically written to correct the thermal effects on the stress relaxation data.
Book Synopsis Composite Materials and Joining Technologies for Composites, Volume 7 by : Eann Patterson
Download or read book Composite Materials and Joining Technologies for Composites, Volume 7 written by Eann Patterson and published by Springer Science & Business Media. This book was released on 2012-09-18 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composite Materials and the First International Symposium on Joining Technologies for Composites, Volume 7: Proceedings of the 2012 Annual Conference on Experimental and Applied Mechanics represents one of seven volumes of technical papers presented at the Society for Experimental Mechanics SEM 12th International Congress & Exposition on Experimental and Applied Mechanics, held at Costa Mesa, California, June 11-14, 2012. The full set of proceedings also includes volumes on Dynamic Behavior of Materials, Challenges in Mechanics of Time -Dependent Materials and Processes in Conventional and Multifunctional Materials, Imaging Methods for Novel Materials and Challenging Applications, Experimental and Applied Mechanics, Mechanics of Biological Systems and Materials and, MEMS and Nanotechnology.
Book Synopsis Bolt Bearing Behavior of Highly Loaded Polymer Matrix Composite Joints at Elevated Temperatures With and Without Clamp-Up by : RJ. Wright
Download or read book Bolt Bearing Behavior of Highly Loaded Polymer Matrix Composite Joints at Elevated Temperatures With and Without Clamp-Up written by RJ. Wright and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data are presented on time-dependent behavior of bolted joints made from 64-ply IM7 carbon fiber/K3B thermoplastic polyimide quasi-isotropic lay-up tested in pure bolt bearing and in bearing bypass. Composite panels were aged at temperatures of 177 and 204°C for 5 000 and 10 000 (h) to simulate cumulative effects of supersonic flight conditions on a bolted composite joint. Changes in joint-bearing capacity and determination of time-dependent behavior have been covered in this study. Test coupons sized and drilled to correspond to the ratios found in actual joints were loaded over a wide range at both with and without clamp-up forces. Testing at 177°C simulated supersonic cruise temperature. Bearing creep testing revealed time-dependent behavior only in a very narrow loading region, above which bearing failure occurred almost instantaneously and below which no damage occurred. Testing of aged material showed degradation in material aged at 177°C for 5000 h; however, material aged at 177°C for 10 000 h demonstrated a recovery in bearing capacity, while material aged at temperatures of 177 and 204°C for 5000 and 10 000 h showed neither increased nor equivalent performance degradation. Testing with neat resin demonstrated that the matrix material becomes more brittle both with temperature and with aging. It was concluded that this material experiences no significant time-dependent deformation for temperatures at or below 204°C.
Book Synopsis Joining Technologies for Composites and Dissimilar Materials, Volume 10 by : Gary L. Cloud
Download or read book Joining Technologies for Composites and Dissimilar Materials, Volume 10 written by Gary L. Cloud and published by Springer. This book was released on 2016-10-08 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Joining Technologies for Composites and Dissimilar Materials, Volume 10 of the Proceedings of the 2016 SEM Annual Conference & Exposition on Experimental and Applied Mechanics, the tenth volume of ten from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on a wide range of areas, including: Composite Joints Non-Adhesive Bonding Adhesive Bonding Joining of Ceramic & Other Materials
Book Synopsis Performance of Bolting Materials in High Temperature Plant Applications by : Andrew Strang
Download or read book Performance of Bolting Materials in High Temperature Plant Applications written by Andrew Strang and published by CRC Press. This book was released on 2020-11-25 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the technology of high-temperature bolting materials and the design considerations of high-temperature bolted joints. It is based on the second international conference on high-temperature creep resistant materials held in York.
Book Synopsis Duration of Load on Bolted Joints by : Thomas Lee Wilkinson
Download or read book Duration of Load on Bolted Joints written by Thomas Lee Wilkinson and published by . This book was released on 1988 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Behavior of Composite Bolted Joints at Elevated Temperature by :
Download or read book Behavior of Composite Bolted Joints at Elevated Temperature written by and published by . This book was released on 1979 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Temperature Bolted Joint with Thermal Distortion by :
Download or read book High Temperature Bolted Joint with Thermal Distortion written by and published by . This book was released on 2020 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bolt mechanics has been developed over thousands of years. Today, bolted joints researchers and designers are still facing challenges in many areas especially when a joint works at elevated temperatures. Temperature changes of a bolted joint in such systems induce catastrophic cyclic axial and bending strain to the fasteners and gasket degradation. Now, with many studies, the axial strain issue can be addressed by adjusting the clamping load to maintain the stiffness of the joint or by changing the jointed materials to have appropriate coefficient of thermal expansions (CTE) to have a suitable clamping load. Dealing with the bending strain caused by cyclic thermal changes, however, is more complicated. It is still a big challenge for engine designers and fastener researchers. During heat up and cool down, most bolted joints have dissimilar thermal expansion rate of jointed components or different temperature profiles which will cause bolted joint expansion or contraction motions in axial and transverse directions. The amplitude of the bolt transverse motion is called bending motion in this dissertation which is associated with the relative motions between jointed components and bolt head. Friction force acting on the bolt head bearing area causes the bolt bending motion resulting in bolt bending fatigue. In this research, mathematical modeling and FEA methods have been employed to specify the design space based on the high temperature bolted joint operating conditions. The design target can be defined based on design control factors including demission, materials and operating temperature of the bolted joint. With this developed method, a specific high temperature bolted joint has been designed with a frictional target of the bolted joint. To meet this target, a series of tribological bench tests were conducted to evaluate washer with different coatings which have potential good high temperature characteristics under different temperatures. A washer with CrN46 multi-layer coating was found to close to the design target which was effective under high pressure and high temperature with a relatively low coefficient of friction. The tested coating has been analyzed after test and found that, with the aid of the formation of W2C, tungsten could allow the DLC coating to perform well under high temperature environment. This verified J. Luthin and C. Linsmeier finding that the W2C formation starts at 500°C. Delamination is the main wear mechanism for the CrN46 coating, but the wear depth met the design requirement which was 1500 reciprocating cycles. A sensitivity study using Taguchi method was conducted and showed that the dry coefficient of friction depends on many factors, including temperature, materials, surface finishing and sliding speed. The material is the most significant design control factor, which affects the friction coefficient. The CrN46 coasting sliding against CrN46 coasting was found to provide even lower coefficient of friction which was used in the design. Then the design of the joint with the coated washer was validated by engine dyno data which was collected by a novel mutli-camera 3D-DIC system developed in this research. This might be the first time 3D-DIC system has been successfully applied in an engine dyno to measure the displacement of the exhaust manifold and fasteners exposed to high temperatures, mechanical and dynamic loads. This application illustrated that a 3D-DIC system could be applied in a severe thermal and vibration environment with a proper system design. The data collected by the 3D-DIC system was compared to traditional LVDT data. It showed that 3D-DIC was reliable and could provide whole field contour data. The measured data has been used to validate the CAE analysis and improve the computational methodology. Measuring the strain field was still a challenge for this 3D-DIC system because of the high thermal strain generated at high temperature. A high-resolution speckle pattern was needed as well. To systematically address the high temperature bolt joint with thermal deformation, a robust CAE method for the MLS gasket design has been developed to overcome the current design method which was not an effective method to evaluate MLS gasket sealing performance with consideration of gasket material thermal degradation. A new method was developed in this research. In the new method, a thermal degradation factor was used to correct the gasket sealing pressure calculated by the current CAE method. With the new method, it was found that a gasket with high thermal degradation resistance showed better sealing performance than a gasket with low thermal degradation resistance, while the current CAE method could not have predicted any difference. The results from the new method matched with the dyno real engine test observation very well and can be used for high temperature bolted joint designs. Overall, this research found a metrology to predefine a friction requirement and a robust "engineed refiles"/"engineered coated washer" to provide a robust hig temperature bolted joint design. Four main sections were focused on in this research. The first was developing a systematic method which combined virtual analyses with bench tests to develop a low friction coated washer to solve the bolt bending fatigue issue due to the engine cyclic thermal changes. The second was to design tests to validate the performance of the low friction coated washer to meet the predefined frictional requirements. The third was to improve a process for virtual analysis for the high temperature bolted joint with more accurate temperature simulation and frictional interface model. The fourth was to develop a method to predict the gasket sealing behavior at the elevated temperature when considering the creep and relaxation of the bolted joint. The objective of this research has been met by the complete of the below tasks. 1. Developed a systematic method for designing a high temperature bolted joint for bolt bending fatigue. 2. A coating has been developed and evaluated by a series of A bench tests to solve the bolt bending fatigue issue due to the engine cyclic thermal changes. 3. A unique multi-camera 3D-DIC system has been successfully designed and applied in an engine dyno to measure the displacement of the exhaust manifold and fasteners exposed to high temperatures, mechanical and dynamic loads. 4. Virtual analysis method for the high temperature bolted joint has been improved with more accurate temperature simulation and frictional interface model. 5. Developed a method to predict the gasket sealing behavior at the elevated temperature with consideration of the creep and relaxation of the bolted joint. 6. Design and method have been validated by engine dyno tests.
Book Synopsis The Mechanics of Threaded Fasteners and Bolted Joints for Engineering and Design by : Toshimichi Fukuoka
Download or read book The Mechanics of Threaded Fasteners and Bolted Joints for Engineering and Design written by Toshimichi Fukuoka and published by Elsevier. This book was released on 2022-10-22 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mechanics of Threaded Fasteners and Bolted Joints outlines how threaded fasteners and bolted joints fail, how these failures can be remedied, and ultimately how to avoid them altogether through tightening methods, material strength, and avoiding loosening. The book demonstrates how to select the appropriate tightening method and determine the optimal tightening procedure for varying nominal diameters. Using the finite element method, it discusses characteristics of stress concentration and fatigue strength and covers bolt force variation due to elastic interaction. The separation of the plate interface via increased external force as the primary cause of fatigue failure in threaded fasteners is discussed, with effective countermeasures provided. Empirical equations of thermal contact coefficient and apparent thermal contact coefficient in simple form are included as well.?? Outlines various tightening methods such as torque control, angle control, direct tension, and thermal expansion Demonstrates methods for preventing fatigue failure Discusses the effect of high and low temperature thermal loads on the strength of bolted joints by looking at thermal contact resistance at the interface
Book Synopsis Influence of Stress Relaxation in Hybrid Composite/Metal Bolted Connections by :
Download or read book Influence of Stress Relaxation in Hybrid Composite/Metal Bolted Connections written by and published by . This book was released on 2005 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of the influence of stress relaxation on watertight integrity of hybrid composite-to-metal bolted connections is presented. This study focuses on the effects of bolt reloading, use of tapered-head bolts versus protruding-head bolts, and briefly addresses environmental effects. All tests were conducted for a time period of at least three months, in order to estimate primary and secondary stress relaxation effects. The reloading tests show that some of the preload in the connections can be maintained with periodic retightening of the bolts. In a limited amount of testing it was observed that temperature shifts caused more rapid stress relaxation rates. Little difference in relaxation was observed when comparing tapered-head bolts with protruding-head bolts, given that roughly equal stress relaxation rates were observed. Further research on this area is required.
Book Synopsis Creep Elongation of Bolt Holes Subjected to Bearing Loads in a Polymer Matrix Composite Laminate by : AR. Kallmeyer
Download or read book Creep Elongation of Bolt Holes Subjected to Bearing Loads in a Polymer Matrix Composite Laminate written by AR. Kallmeyer and published by . This book was released on 1997 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: To assess the long-term durability of advanced composite joints, the localized creep response of a quasi-isotropic ([45/0/-45/90]2s), graphite fiber/polymer matrix (G40-800/5260) composite laminate subjected to bolt-bearing loads at ambient and elevated temperatures was investigated. Monotonic tension tests and static creep tests were performed on single-hole bolted joints at temperatures of 23, 100, and 150°C. The influence of lateral constraint on the creep response was studied by performing creep tests with bolt clampup torques of 5.65 N.m and a "finger-tight" level. While the ultimate monotonic bearing strength was affected only marginally by temperature, substantial changes in the initial joint stiffness and the hole elongation at fracture were observed in the monotonie tests as the temperature was increased. In the creep tests, significant time-dependent hole elongations were observed at high bearing stress levels and temperatures, with the creep component of the hole elongation found to exceed 5% of the original hole diameter in one case. The lateral constraint had a large influence on the creep behavior of the joints. As the clampup torque was reduced from 5.65 N.m to a finger-tight level, the rate of hole elongation increased by a factor of 2 to 4, indicating the importance of maintaining high clampup conditions in bolted laminate joints. A simple empirical expression was proposed to model the creep behavior of the joints. This expression correlated the experimental data reasonably well and is useful for indicating trends in the creep response of bolted laminate joints.
Book Synopsis Three-dimensional Strain Analysis of Single-lap Bolted Joints in Thick Composites Using Fiber-optic Strain Gages and Finite Element Method by : Gabriel A. Isaicu
Download or read book Three-dimensional Strain Analysis of Single-lap Bolted Joints in Thick Composites Using Fiber-optic Strain Gages and Finite Element Method written by Gabriel A. Isaicu and published by . This book was released on 2006 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mechanics of Hybrid Bonded-bolted Joints by : Kobyé Bodjona
Download or read book Mechanics of Hybrid Bonded-bolted Joints written by Kobyé Bodjona and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Large mechanical structures, for example aircraft and motor vehicles, usually consist of a number of subassemblies. This necessitates the use of joints, which locate the subassemblies and transfer loads between them. While necessary, joints introduce discontinuities into the structure that act as stress raisers and regions of possible failure initiation. Consequently, joint design is crucial for achieving satisfactory structural strength.Joining composite structures is all the more challenging compared to metallic structures. This is due to the brittle nature of many composite materials, which permits only modest plastic deformation and limits the corresponding mitigation of stress concentrations prior to fracture. This is particularly problematic for bolted composite structures. In order to fully exploit the potential of composites, it is thus necessary to develop more efficient means of joining them. In recent years, several investigators have shown experimentally that a combination of bonding and bolting can, sometimes, produce a joint that is stronger than either of these joints by itself. This could potentially result in a more efficient joint and is therefore of particular interest for composite structures. These investigators found that load sharing between the adhesive and bolt is important for achieving the benefits of "hybridization". However, they had only limited understanding of the most effective way to achieve load sharing. Furthermore, they made no attempt to predict the strength of hybrid joints by means of mathematical modelling.In response to these shortcomings in the literature, this thesis follows a two-pronged approach. First, in Chapters 3-4, load sharing in hybrid bonded-bolted joints is addressed. An efficient numerical model is developed in Chapter 3 for this end. This model is validated experimentally, after which it is used in a global sensitivity analysis in Chapter 4 to determine the most important factors influencing load sharing. Of the various parameters considered, it is found that the adhesive yield strength, overlap length and adhesive hardening modulus have the greatest effects, by a considerable margin.Next, in Chapters 5-10, strength is addressed. For this purpose, an original mathematical model of a hybrid bonded-bolted joint is developed from first principles. This model distills the physical problem to the essentials, yet accounts for many complex effects found in real joints. Through comparison with the experimental results presented in Chapter 10, the model is shown to be capable of providing a basic prediction of bonded-, bolted-, and hybrid-bonded-bolted joint strength. Agreement to within 8% of the experiment is demonstrated. The model is subsequently used to elucidate key behaviours of hybrid bonded-bolted joints in Chapter 11.Based on the findings of this thesis, increased confidence has been established in the feasibility of the hybrid bonding-bolting concept. Furthermore, the developed analysis methodology has demonstrated significant promise for use as part of a design tool." --
Book Synopsis Bolted Joints in Composites Primary Structures by : A. Ruiz
Download or read book Bolted Joints in Composites Primary Structures written by A. Ruiz and published by . This book was released on 1988 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the design of composite parts in primary structures, it is necessary to use bolted joints because of inspection requirements and the need for partial disassembly, repairability, access to the structure and for manufacturing breaks. The proven methodology for bolted joints in metallic structures cannot directly be applied to bolted joints in composites because of: Material anisotropy, susceptibility to the environment and, specially, due to the brittle behaviour of typical carbon/epoxy joint members up to ultimate failure. In typical highly loaded multirow joints, a tension type failure generally occurs. Peak tangencial stresses at the edge of fastener hole produces fibres break-out. Stress concentration factors governs the failure, as in metal joints under fatigue loads. A methodology for composite bolted joints analysis must be able to size any particular joint design, avoiding the need for detail design tests. The approach under the present work is based on a methodology developed by J.L. Hart-Smith (Douglas. Long Beach) which correlates stress concentration factors in elastic-isotropic materials with those which appear in composites, by means of an empirically determined 'relief' factor. CASA has developed a test plan which includes several hundreds of coupons. Basically, bearing strength allowables and stress concentration factors, are investigated. The plan covers double and single shear specimens, environmental effects (cold-dry and hot-wet), different resin systems and fasteners, and various loading conditions. Provisions for evaluating hole size effect are also made. (SDW).
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1994 with total page 898 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of Key Parameters for Reliable Tightening and In-service Behavior of Bolted Joints by : Saravanan Ganeshmurthy
Download or read book Investigation of Key Parameters for Reliable Tightening and In-service Behavior of Bolted Joints written by Saravanan Ganeshmurthy and published by . This book was released on 2013 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reliability and stability of any bolted joint depends on the level and stability of clamp load generated by the tightening process. Hence, it very critical to understand the role of key process control parameters that affect the tightening process and also how in-service loads can affect the clamp load in a joint. This Ph.D. dissertation investigates the effect of key process control parameters like tool speed and multi-stage tightening on the torque-tension relationship, and discusses the evolution of the friction torque components during initial tightening and subsequent audit tightening and/ or breakaway loosening stages. It also presents a method to create a non-linear three dimensional finite element model which takes in to account the thread helix angle. Results from finite element analysis for the torque-only process control method are in good agreement with the torque-tension predictions provided by the Motosh equation. The presence of non-parallel contact under the bolt head is investigated, along with other process variables like friction, thread clearance, bolt hole clearance, and grip length. Novel methods to simulate bolt tightening process control methods like torque-turn, tension control and bolt elongation or stretch control and presented and discussed. To understand the effect of in-service loads on the behavior of bolted joints, the dissertation provides a study which utilizes a three dimension finite element model to simulate and evaluate the cumulative loss in clamp load in a bolted joint that is tightened beyond its proportional limit. The joint is subjected to a fully reversed cyclic load that is applied at the bolt axis or away from the bolt axis to capture the effect of eccentric loading. An extensive survey of the literature on process control parameters, finite element analysis of bolted joints and clamp load loss in bolted joints under external loads has been included. The results presented and discussed in this dissertation, provide valuable information that will help design a more reliable joint.
