Progressive Failure Analysis of an Integral Composite Joint for Thrust Reverser Cascade

2019 ◽  
Vol 795 ◽  
pp. 325-332
Author(s):  
Ji Shen Yang ◽  
Hong Yu Qi ◽  
Xiao Guang Yang ◽  
Duo Qi Shi
Keyword(s):  
Carrying Capacity ◽  
Composite Structure ◽  
Progressive Failure ◽  
Damage Model ◽  
Research Work ◽  
Failure Behavior ◽  
Load Carrying Capacity ◽  
Composite Joint ◽  
Bending Load ◽  
Load Carrying

The research work in this paper is focused on studying the failure behavior of an integral π-shaped laminated composite structure subjected to a bending load. A progressive damage model based on the 3D Tsai-Wu failure criterion and a developed gradual degradation model was employed to simulate and assess the load-carrying capacity, the onset and propagation of damage, and the failure mechanisms. For this unique π-shaped composite structure, disbonding was found to be the dominant damage mode under bending load, and the approximate maximum load could be maintained for a brief time during the final failure due to the gradual loss nature of the load-carrying capacity. The extent of damage was found to be more serious on the side of Rib II compared to the other side.

Influence of water contamination in gear lubricants on wear and micro-pitting performance of case carburized gears

2017 ◽  
Vol 69 (4) ◽  
pp. 612-619 ◽  
Author(s):  
Christian Engelhardt ◽  
Jochen Witzig ◽  
Thomas Tobie ◽  
Karsten Stahl
Keyword(s):  
Carrying Capacity ◽  
Research Work ◽  
Load Carrying Capacity ◽  
Wear Performance ◽  
Content Type ◽  
Effect Of Water ◽  
Base Oils ◽  
Load Carrying ◽  
Different Types ◽  
Influence Of Water

Purpose Water can alter the performance of modern gear lubricants by influencing the flank load carrying capacity of gears significantly. The purpose of this paper is to investigate the influence of water contaminations in different kinds of base oils on the micro-pitting and wear performance of case carburized gears. Design/methodology/approach Concerning micro-pitting and wear, tests, based mostly on the following standardized tests, are performed on a Forschungsstelle fuer zahnraeder und getriebebau (FZG)-back-to-back gear test rig: micro-pitting short test Graufleckenkurztest (GFKT) according to DGMK 575 (screening test), micro-pitting test Graufleckentest (GT) according to FVA 54/7 (load stage test and endurance test) and Slow-speed wear test according to DGMK 377. To investigate the effect of water on the gear load carrying capacity dependent on different types of base oils, two polyglycol oils (PG1 and PG2), a polyalphaolefin oil, a mineral oil and an ester oil E are used. Each of these oils are common wind turbine gear oils with a viscosity ISO VG-220. Additionally, a manual transmission fluid with a viscosity of society of automotive engineers (SAE) 75W-85 is tested. Findings Considering the micro-pitting and wear performance, a significant decrease caused by water contaminations could not be detected. Regarding pitting damages, a generally negative influence was observed. This influence was differently distinctive for different base oil types. Especially non-polar lubricants seem to be affected negatively. The documented damages of the tooth flanks confirm this observation. While typical pitting damages appeared in test runs with polar lubricants, the disruption in test runs with non-polar lubricants was more extensive. Based on the experimental investigations, a general model of the damaging mechanisms of water contaminations in lubricants was derived. It is split into three partitions: interaction lubricant–water (effect of water on the molecular structure of base oils and additives), chemical-material-technological (especially corrosive reactions) and tribological influence (effect of water droplets in the contact zone). It has to be considered that the additive package of lubricants affects the influence of water contaminations on the flank load carrying capacity distinctively. An influence of water on the micro-pitting and wear performance in other than the given lubricants cannot be excluded. Originality/value While former research work was focused more on the effects of water in mineral oils, investigations concerning different types of base oils as well as different types of damages were carried out within this research project.

scholarly journals Comparison of Load Carrying Capacity of Three and Four Lobed Polygonal Shaft and Hub Connection for Constant Grinding Diameter

2016 ◽  
Author(s):  
Ravi Bhatta ◽  
Wendy Reffeor
Keyword(s):  
Carrying Capacity ◽  
Power Transmission ◽  
Axial Stress ◽  
Von Mises Stress ◽  
Load Carrying Capacity ◽  
Interference Fit ◽  
Bending Load ◽  
Load Carrying ◽  
Von Mises ◽  
Conformal Contact

Polygonal shafts are used in power transmission as alternatives to keyed and splined shafts. They are designed using DIN standards. This research explores the loading strength of the standardized three lobed (P3G) and four lobed (P4C) polygonal shafts and hubs manufactured from the same stock size, subjected to torsional bending load at various fits. Due to complex conformal contact (nonlinear model) between the shaft and the hub, there is no analytical solution and, therefore, Finite Element Method had been used to determine the stresses, after validating experimentally and using the DIN standard. From the analysis, it was found that the hub experienced greater stress than the shaft in all cases and the major stress in a polygonal shaft and hub connection is the contact stress. The clearance fit was found to be the most detrimental fit and the interference fit to be the most suitable for larger power transmission. Owing to its small normal axial stress and hub displacement, the P4C clearance fit has its use in low power transmission where a sliding fit is a requirement. The maximum von Mises stress was located below the surface for P4C and P3G clearance fit, suggesting failure from pitting and fretting on these shafts. All of the stresses were found to be higher in P4C than P3G for similar loading. Therefore, for general use, the P3G profile with an interference fit is recommended.

An Experimental Study on the Evaluation of Failure Behavior of Pipe With Local Wall Thinning

2002 ◽  
Author(s):  
Jin Weon Kim ◽  
Chi Yong Park
Keyword(s):  
Internal Pressure ◽  
Failure Mode ◽  
Carrying Capacity ◽  
Axial Length ◽  
Failure Behavior ◽  
Load Carrying Capacity ◽  
Wall Thinning ◽  
Load Carrying ◽  
Deformation Ability ◽  
Local Wall Thinning

The pipe failure tests were performed using 102mm-Sch.80 carbon steel pipe with various simulated local wall thinning defects, in the present study, to investigate the failure behavior of pipe thinned by flow accelerated corrosion (FAC). The failure mode, load carrying capacity, and deformation ability were analyzed from the results of experiments conducted under loading conditions of 4-point bending and internal pressure. A failure mode of pipe with a defect depended on the magnitude of internal pressure and axial thinning length as well as stress type and thinning depth and circumferential angle. Also, the results indicated that the load carrying capacity and deformation ability were depended on stress state in the thinning region and dimensions of thinning defect. With increase in axial length of thinning area, for applying tensile stress to the thinning region, the dependence of load carrying capacity was determined by circumferential thinning angle, and the deformation ability was proportionally increased regardless of the circumferential angle. For applying compressive stress to thinning region, however, the load carrying capacity was decreased with increase in axial length of the thinned area. Also, the effect of internal pressure on failure behavior was characterized by failure mode of thinned pipe, and it promoted crack occurrence and mitigated a local buckling of the thinned area.

scholarly journals Stability and Load-Carrying Capacity of Thin-Walled FRP Composite Z-Profiles under Eccentric Compression

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2956
Author(s):  
Hubert Debski ◽  
Sylwester Samborski ◽  
Patryk Rozylo ◽  
Pawel Wysmulski
Keyword(s):  
Composite Material ◽  
Carrying Capacity ◽  
Progressive Failure ◽  
Compressive Load ◽  
Experimental Tests ◽  
Numerical Results ◽  
Load Carrying Capacity ◽  
Plastic Composite ◽  
Load Carrying ◽  
Thin Walled

This study investigates the effect of eccentric compressive load on the stability, critical states and load-carrying capacity of thin-walled composite Z-profiles. Short thin-walled columns made of carbon fiber-reinforced plastic composite material fabricated by the autoclave technique are examined. In experimental tests, the thin-walled structures were compressed until a loss of their load-carrying capacity was obtained. The test parameters were measured to describe the structure’s behavior, including the phenomenon of composite material failure. The post-critical load-displacement equilibrium paths and the acoustic emission signal enabling analysis of the composite material condition during the loading process were measured. The scope of the study also included performing numerical simulations by finite element method to solve the problem of non-linear stability and to describe the phenomenon of composite material damage based on the progressive failure model. The obtained numerical results showed a good agreement with the experimental characteristics of real structures. The numerical results are compared with the experimental findings to validate the developed numerical model.

Analysis of shear behavior between old concrete and fiber concrete

2021 ◽  
Author(s):  
Martin Vavruš ◽  
Peter Koteš ◽  
František Bahleda ◽  
Jozef Jošt
Keyword(s):  
Carrying Capacity ◽  
Research Work ◽  
Concrete Structures ◽  
Mechanical Damage ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Fiber Concrete ◽  
Different Types ◽  
Thawing And Freezing Cycles

AbstractConcrete structures that are influenced by degradation, overloading, the thawing, and freezing cycles, corrosion of reinforced bars, should be repaired or strengthened. Each of the mentioned influences lead to decreased load-carrying capacity of the structure or its member. Exceeding the load-carrying capacity leads to mechanical damage of members or excessive deformation. The damaged member has to be strengthened to the required level of reliability and load-carrying capacity. There exist many types and methods of strengthening the columns. This research work deals with strengthening of columns by concreting a new layer of fiber concrete. When applying that type of strengthening, it is necessary to assure the contact between the old layer and the new one. The paper deals with analysis of different types of contacts and determination of their parametric values.

Effect of CFRP Thickness on Load-Carrying Capacities and Failure Modes of Strengthened RC Beams

2011 ◽  
Vol 255-260 ◽  
pp. 109-112
Author(s):  
Guo Wen Yao ◽  
Mao Sheng Li ◽  
Shi Ya Li
Keyword(s):  
Carrying Capacity ◽  
Failure Modes ◽  
Mechanical Analysis ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Bending Load ◽  
Load Carrying ◽  
Carbon Fiber Laminate ◽  
Externally Bonded ◽  
Ultimate Loading

The effect of thickness of externally bonded carbon fiber laminate (CFRP) on load-carrying capacity and failure modes was analyzed for the strengthened reinforced concrete (RC) beams under bending load. According to the balance equations of applied force and moment, the relation was obtained between ultimate loading of strengthened beam and thickness of CFRP, and the failure modes were predicted for the CFRP strengthened beams. The load-carrying capacity of strengthened RC beam is higher with thicker externally bonded CFRP until it reaches the ultimate loading. The mechanical analysis is in good agreement with the three-point bending experiments performed on CFRP strengthened RC beams.

Numerical Prediction of Maximum Load-Carrying Capacity of Cracked Alloy 690TT Steam Generator Tubes

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Jun-Young Jeon ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Kuk-Hee Lee ◽  
Jong-Sung Kim
Keyword(s):  
Steam Generator ◽  
Test Data ◽  
Carrying Capacity ◽  
Damage Model ◽  
Maximum Load ◽  
Simulation Method ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Steam Generator Tubes ◽  
Strain Model

This paper presents a finite element (FE) simulation technique to predict maximum load-carrying capacity of cracked steam generator tubes and its application to Alloy 690TT tubes. The simulation method is based on a simplified version of the stress modified fracture strain model. The damage model is determined from tensile test and one cracked tube test data. Predicted maximum pressures are compared with 23 test data of axial through-wall and surface cracked Alloy 690TT steam generator tubes. Comparison with experimental data shows good agreement.

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