Pitting Resistance and Bending Strength of Bevel and Hypoid Gear Teeth

Author(s):  
B.-R. Höhn ◽  
H. Winter ◽  
K. Michaelis ◽  
F. Vollhüter

Abstract Bevel and hypoid gears are widely used for gears with crossed axis. The influence of a pinion offset on the load carrying capacity — pitting resistance and bending strength — is introduced in a different way in commonly used calculation methods. Load carrying and measurement investigations on the influence of pinion offset on pitting resistance and bending strength are reported. Tests show an increasing bending strength and decreasing maximum tooth root stresses with increasing pinion offset. Also a slight increase of pitting resistance and a slight decrease of the Hertzian pressure was evaluated. The load carrying calculation results for bevel gears without pinion offset, DIN 3991, is in good agreement with test results. The bending strength of hypoid gears calculated according to Niemann/Winter, is greater than that experimentally measured. For pitting resistance, however, the calculation is less than the measured results.

2010 ◽  
Vol 133-134 ◽  
pp. 1233-1239
Author(s):  
Li Xue Jiang ◽  
Feng Zhou ◽  
Qiao Wen Zheng

Four steel beam-column connections were tested under cyclic loads to investigate effects of the concrete cover and the cast-in-situ slabs on the failure modes, stiffness, load-carrying capacity, ductility and energy-dissipation capacity. The test results show that the stiffness and bending strength of the non-rigid steel connections are significantly increased due to the presence of concrete cover and the cast-in-situ slabs can further enhance the connections. Moreover, the connection with slab is prone to debonding failure along beam-slab interface resulting in a remarkable decrease of the stiffness and strength. Practical methods are also presented for analyzing and assessing the steel frames with non-rigid connections considering effects of concrete cover.


Author(s):  
Daniel Müller ◽  
Jens Stahl ◽  
Anian Nürnberger ◽  
Roland Golle ◽  
Thomas Tobie ◽  
...  

AbstractThe manufacturing of case-hardened gears usually consists of several complex and expensive steps to ensure high load carrying capacity. The load carrying capacity for the main fatigue failure modes pitting and tooth root breakage can be increased significantly by increasing the near surface compressive residual stresses. In earlier publications, different shear cutting techniques, the near-net-shape-blanking processes (NNSBP’s), were investigated regarding a favorable residual stress state. The influence of the process parameters on the amount of clean cut, surface roughness, hardness and residual stresses was investigated. Furthermore, fatigue bending tests were carried out using C-shaped specimens. This paper reports about involute gears that are manufactured by fineblanking. This NNSBP was identified as suitable based on the previous research, because it led to a high amount of clean cut and favorable residual stresses. For the fineblanked gears of S355MC (1.0976), the die edge radii were varied and the effects on the cut surface geometry, hardness distribution, surface roughness and residual stresses are investigated. The accuracy of blanking the gear geometry is measured, and the tooth root bending strength is determined in a pulsating test rig according to standardized testing methods. It is shown that it is possible to manufacture gears by fineblanking with a high precision comparable to gear hobbing. Additionally, the cut surface properties lead to an increased tooth root bending strength.


2020 ◽  
Vol 327 ◽  
pp. 03004
Author(s):  
D. Santana Sanchez ◽  
A. Mostafa

The present paper discusses the design analysis and limitations of the steering system of a buggy. Many geometrical and performance characteristics of the designed steering system were considered to address the kinematic constraints and load carrying capacity of the steering elements. Ackremann geometry approach was used to assess the limiting steering angle, while Lewis bending formula with the inclusion of dynamic effects was employed to characterise the flexural properties of the rack and pinion steering system. Analytical results were numerically verified using ABAQUS/Explicit nonlinear finite element (FE) package. Good agreement has been achieved between analytical and numerical results in predicting the flexural behaviour of the steering rack and pinion system.


2021 ◽  
Vol 28 (1) ◽  
pp. 71-83
Author(s):  
Mazin Abdulrahman ◽  
Shakir Salih ◽  
Rusul Abduljabbar

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively Using CFRP .


2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Brian Nyvang Legarth ◽  
Qingda Yang

Failure in elastic dual-phase materials under transverse tension is studied numerically. Cohesive zones represent failure along the interface and the augmented finite element method (A-FEM) is used for matrix cracking. Matrix cracks are formed at an angle of 55 deg−60 deg relative to the loading direction, which is in good agreement with experiments. Matrix cracks initiate at the tip of the debond, and for equi-biaxial loading cracks are formed at both tips. For elliptical reinforcement the matrix cracks initiate at the narrow end of the ellipse. The load carrying capacity is highest for ligaments in the loading direction greater than that of the transverse direction.


1987 ◽  
Vol 2 (3) ◽  
pp. 77-80 ◽  
Author(s):  
Marvin R. Pyles ◽  
Joan Stoupa

Abstract In order to quantify the stump anchor capacity of small second-growth Douglas-fir (Pseudotsuga menziesii [Mirb]. Franco) trees, load tests to failure were conducted on 18 stumps from trees 7 to 16.5 in dbh. The tests produced ultimate loads that varied as the square of the tree diameter. However, the ultimate load typically occurred at stump system deformations that were far in excess of that which would be considered failure of a stump anchor. A hyperbolic equation was used to describe the load-deformation behavior of each stump tested and was generalized to describe all the test results. West. J. Appl. For. 2(3):72-80, July 1987.


2019 ◽  
Vol 22 (13) ◽  
pp. 2755-2770
Author(s):  
Fuyun Huang ◽  
Yulong Cui ◽  
Rui Dong ◽  
Jiangang Wei ◽  
Baochun Chen

When casting wet concrete into hollow steel tubular arch during the construction process of a concrete-filled steel tubular arch bridge, an initial stress (due to dead load, etc.) would be produced in the steel tube. In order to understand the influence of this initial stress on the strength of the concrete-filled steel tubular arch bridge, a total of four single tubular arch rib (bare steel first) specimens (concrete-filled steel tubular last) with various initial stress levels were constructed and tested to failure. The test results indicate that the initial stress has a large influence on the ultimate load-carrying capacity and ductility of the arch structure. The high preloading ratio will reduce significantly the strength and ductility that the maximum reductions are over 25%. Then, a finite element method was presented and validated using the test results. Based on this finite element model, a parametric study was performed that considered the influence of various parameters on the ultimate load-carrying capacity of concrete-filled steel tubular arches. These parameters included arch slenderness, rise-to-span ratio, loading method, and initial stress level. The analysis results indicate that the initial stress can reduce the ultimate loading capacity significantly, and this reduction has a strong relationship with arch slenderness and rise-to-span ratio. Finally, a method for calculating the preloading reduction factor of ultimate load-carrying capacity of single concrete-filled steel tubular arch rib structures was proposed based on the equivalent beam–column method.


Author(s):  
André Sitzmann ◽  
Thomas Tobie ◽  
Karsten Stahl ◽  
Stefan Schurer

Abstract The load carrying capacity of highly loaded gears can be increased by thermochemical surface treatments such as nitriding or case hardening. In contrast to case hardening, the nitriding treatment is carried out at lower process temperatures and therefore creates lower distortion. As a result, grinding after nitriding is usually not necessary. Nitrided gears are ordinarily characterized by a thin, high-hardness, a few micrometers thick compound layer of iron and alloy element nitrides directly on the surface and a subsequent diffusion layer reaching more deeply into the material. Nitriding, therefore, provides an alternative to case hardening for distortion-sensitive components and offers potential for cost savings in the production of highly loaded gears. This publication will focus on the influence of nitriding on the load carrying capacity of highly loaded gears. In addition, this paper summarizes the current state of knowledge of nitrided gears and gives an insight into current research in the field of nitrided gears. In particular, the influence of the compound layer on the tooth root bending strength and the flank load carrying capacity achieved within the research project FVA 386 II is discussed.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xuezeng Liu ◽  
Yunlong Sang ◽  
Shuang Ding ◽  
Guiliang You ◽  
Wenxuan Zhu ◽  
...  

Cracks and other diseases may occur in the long-term operation of highway tunnels and reduce the structural load-carrying capacity. Strengthening using carbon fiber reinforced polymer (CFRP) sheets and other materials could extend the service time of the tunnels. However, the process of strengthening tunnels is remarkably different from the process of strengthening aboveground structures because of the secondary load. In order to understand the development of stress and deformation of strengthened tunnels under secondary load, a 1 : 10 scaled model was tested to simulate the tunnel strengthened with CFRP under different damage states. The test results show that CFRP strengthening improved the stiffness of the structure and inhibited the propagation of the existing cracks. The peeling of the CFRP sheets made the strengthened structure quickly lose its load-carrying capacity, causing the instability of the structure. The failure loads of the structures strengthened at different damage states were essentially the same, with an average value of 184% of the original failure load. Nevertheless, the early strengthening helped control the structural deformation. The test results also demonstrate that the bonding strength between the CFRP and the lining is essential for strengthening effectiveness. This study provides a theoretical basis for similar engineering reinforcement designs.


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