scholarly journals Discussion: “Internal Force and Moment Transmission in a Cardan Joint With Manufacturing Tolerances” (Fischer, I., and Freudenstein, F., 1984, ASME J. Mech. Transm. Autom. Des., 106, pp. 301–312)

1985 ◽  
Vol 107 (1) ◽  
pp. 141-142
Author(s):  
Elmer R. Wagner
1984 ◽  
Vol 106 (3) ◽  
pp. 301-311 ◽  
Author(s):  
I. S. Fischer ◽  
F. Freudenstein

The literature on the internal forces in Cardan joints, which is sparse, tacitly assumes the vanishing of certain force components. For a joint of ideal proportions the torque transmission has been analyzed, but the force transmission has been only partially developed. In this investigation the displacement analysis and static force and torque analysis of a Cardan joint with manufacturing tolerances has been derived. The forces have been shown to be statically indeterminate by a degree of three. An experiment was undertaken to check on the validity of the assumed vanishing of the abovementioned force components. For the particular joint tests this assumption was not valid. Based on the displacement analysis, which includes the axial sliding at the joints in the presence of manufacturing errors, optimum tolerances can be determined in the design stage. Further experimentation is recommended in order to determine representative magnitudes of the abovementioned axial joint forces in joints of varying constructions and sizes. Together with the static analysis which has been developed in this investigation this will permit the sizing of universal joints in the design stage.


Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 174
Author(s):  
Johannes Seidel ◽  
Stephan Lippert ◽  
Otto von Estorff

The slightest manufacturing tolerances and variances of material properties can indeed have a significant impact on structural modes. An unintentional shift of eigenfrequencies towards dominant excitation frequencies may lead to increased vibration amplitudes of the structure resulting in radiated noise, e.g., reducing passenger comfort inside an aircraft’s cabin. This paper focuses on so-called non-structural masses of an aircraft, also known as the secondary structure that are attached to the primary structure via clips, brackets, and shock mounts and constitute a significant part of the overall mass of an aircraft’s structure. Using the example of a simplified fuselage panel, the vibro-acoustical consequences of parameter uncertainties in linking elements are studied. Here, the fuzzy arithmetic provides a suitable framework to describe uncertainties, create combination matrices, and evaluate the simulation results regarding target quantities and the impact of each parameter on the overall system response. To assess the vibrations of the fuzzy structure and by taking into account the excitation spectra of engine noise, modal and frequency response analyses are conducted.


2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.


Author(s):  
Nagaraja S. Rudrapatna ◽  
Richard R. Bohman ◽  
Jonathan K. Anderson ◽  
Rudolph Dudebout ◽  
Richard Hausen

Jet fuel flowing through the fuel injector is atomized and then mixed with high temperature compressed air flowing through the swirler to create a combustible mixture inside a gas turbine combustor. Individual geometric and flow features are carefully tuned at a component level to deliver optimum combustion performance. In a critical interface such as the fuel injector and swirler, manufacturing tolerances not only have an impact on combustor performance and operability but also on durability, as the relative position of the fuel injector to the swirler significantly impacts the swirler temperature. This paper studies the influence of manufacturing tolerances on component assembly and the resulting impact on swirler temperature. The oxidation damage mechanism of the swirler is used as a measure to assess swirler durability. A Pareto chart of the effect of manufacturing tolerances on metal temperature is used to highlight the key influencing parameters. Probability distribution associated with manufacturing tolerances is gathered with Monte Carlo simulation to guide the design.


Author(s):  
H. Lüdeke ◽  
R. von Soldenhoff

AbstractTo determine allowable tolerances between successive suction panels at hybrid laminar wings with suction surfaces, direct numerical simulations of Tollmien–Schlichting waves over different steps are carried out for realistic suction rates on a wind tunnel configuration. Simulations at given suction panel positions over forward and backward facing steps are carried out by the use of a high-order method for the direct simulation of Tollmien–Schlichting wave growth. Comparisons between high-fidelity direct numerical simulations and quick linear stability calculations have shown capabilities and limits of the well-validated linear stability theory design approach.


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