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Resistance to Wear
Published in Harry J. Meigh, Cast and Wrought Aluminium Bronzes, 2018
Reversing or intermittent loading result in repeated stressing and un-stressing which give rise to fatigue. It is particularly prevalent in rolling contact as in ball bearings and gears and may also be caused by the hammering action of cavitation. Fatigue may in time lead to the formation of cracks at or below the surface and hence ultimately to spalling (chips or fragments of metal breaking off) and delamination wear. Aluminium bronze is reputed for its excellent fatigue resistant properties. Fatigue is greatly affected by surface conditions such as hardness and finish, by the structure of the alloy, by residual stresses and by freedom from internal defects. Generous fillets and fine finish reduce the high notch or stress- concentration factors that can lead to accelerated fatigue failure.159
Shaft Design Basics
Published in Keith L. Richards, Design Engineer's Sourcebook, 2017
When there is a change in the diameter of a shaft to create a shoulder against which to locate a machine element such as a gear or bearing, depending on the ratio of the two diameters and the radius in the fillet, a stress concentration will be generated. It is recommended that the fillet radius r be as large as possible to minimise the stress concentration. At times if the part is proprietary, the designer has no control over the radius and has to accommodate it in the design. For the purpose of design, fillets are classified into two categories: sharp and well rounded (see Figure 21.5).
Joining and Repair
Published in P. K. Mallick, Processing of Polymer Matrix Composites, 2017
The joint design parameters for single-lap bonded joints are the adhesive thickness (h), lap length (L), and substrate end design (Figure 11.12). In order to achieve good bonding and good joint strength, a minimum adhesive thickness is required. As the adhesive thickness is increased above the minimum thickness, the joint strength becomes lower [7,8]. Increasing the lap length results in higher joint strength, but at high lap lengths, the increase in joint strength is relatively small. The ratio of lap length L to substrate thickness h significantly improves the joint strength at small L/h ratios. At high L/h ratios, the improvement is marginal (Figure 11.13). Tapering the substrate ends (Figure 11.14) reduces the high normal stresses at these locations. In many instances, when the pressure is applied during bonding, small amounts of adhesive are squeezed out which form a fillet at the substrate ends. Studies have shown that fillets tend to reduce stress concentration at the joint ends and improve the joint strength.
The effect of adhesive fillet on mechanical performance of adhesively bonded corrugated sandwich structures: an experimental–numerical study
Published in The Journal of Adhesion, 2020
X. Han, G. Akhmet, W. Zhang, Y.X. Chao, Y. Jin, Y. Yu, P. Hu, A. Ibraimov
Finally, it can be seen that the presence of adhesive fillets reduced the peak stress limits and the adhesive fillets can have a major impact on the maximum stress. The stresses cause premature failure in the adhesive joints, but adhesive fillets help to reduce it. For example, by comparing the adhesive fillets’ configurations, it was observed that small fillets’ geometries compared to a larger fillet size caused a smaller reduction of the normal and shear stresses. Therefore, larger fillet size helps to carry a larger portion of the applied load, thereby decreasing the peak stresses even further. Larger length of adhesive fillets will help to improve the strength or stress distribution, but thicker adhesive layer will decrease the performance of the adhesive fillet effect.[26]
Capturing simulation intent in an ontology: CAD and CAE integration application
Published in Journal of Engineering Design, 2019
Flavien Boussuge, Christopher M. Tierney, Harold Vilmart, Trevor T. Robinson, Cecil G. Armstrong, Declan C. Nolan, Jean-Claude Léon, Federico Ulliana
Additional information on simulation-oriented morphology types can benefit from feature recognition techniques which identify specific geometric configurations (e.g. identification of fillets (Venkataraman, Sohoni, and Rajadhyaksha 2002; Zhu and Menq 2002), or ribs (Lai et al. 2018)). Similarly to (Sun et al. 2017a, 2017b), additional segmentation techniques can divide the B-Rep into simpler volumes adapted for a particular FE analysis (Lu, Gadh, and Tautges 2001; Chong, Senthil Kumar, and Lee 2004; Boussuge et al. 2014a; Liu and Gadh 1997; Sun et al. 2017b, 2017a). These techniques can also be used to generate local information on the component shape. However, the extracted regions should still be linked to the component’s purpose and behaviour. For example, a fillet feature should be linked to its mechanical purpose, e.g. avoiding stress concentration.
Structural analysis of spherical pressure hull viewport for manned submersibles using biological growth method
Published in Ships and Offshore Structures, 2018
Pranesh SB, Deepak Kumar, Anantha Subramanian V, Sathianarayanan D, Ramadass GA
The American Society for Testing and Materials (ASTM) approves standard design specimens with notches, with large fixed radius. Variable notch radii help in reducing the stress concentration. Fillets are required in fatigue test specimens to reduce the stress concentration (De Albuquerque Simões et al. 2012). The ASTM standard specifies that the minimum radius of a fillet should be eight times the width of the specimen. Baud (1934) proposed a hydrodynamic analogy to reduce the stresses in the notch regions.