| 1. |
- Östberg, Gustaf
(författare)
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Some reflections on relationships between structure, properties, and performance of engineering materials
- 2003
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Ingår i: Materials & Design. - 0261-3069. ; 24:4, s. 255-262
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Tidskriftsartikel (refereegranskat)abstract
- The main object of materials science and technology is relationships between structure and properties. The practical use of engineering materials also involves consideration of things other than current theories for such relationships. Uncertainties of various kinds prompt reflections on the validity and applications of common practice based on experience. Among other things, this is true for decisions relating to reliability and safety. Hence, fundamental issues like determinism vs. probabilistics may become interesting to anyone who wants to deal efficiently with problems related to the use and performance of engineering materials. (C) 2003 Elsevier Science Ltd. All rights reserved.
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| 2. |
- Östberg, Gustaf
(författare)
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The influence of technical testing methods on perceptions of constructions
- 2002
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Ingår i: Materials & Design. - 0261-3069. ; 23:7, s. 633-640
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Tidskriftsartikel (refereegranskat)abstract
- In principle, methods of testing the reliability and safety of constructions are designed with the aim of representing critical conditions for their use. Because of variations within technical systems, including the one for which a certain test was once developed, the validity of the method also varies. The adoption of a standardized test for different applications had to be based on the assumption that the test deals adequately with a real situation. As a consequence of this acceptance of a trustworthy relationship between test and reality, an imprint of the former on the latter occurs. This effect may even cause the perception of a reality to be defined by the corresponding test. Examples of such an influence may be found in the field of materials testing. Related phenomena can be dealt with by reference to current concepts of cognitive science and psychology of the perception of images. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 3. |
- Ljungberg, Lennart Y., et al.
(författare)
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Design, materials selection and marketing of successful products
- 2003
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Ingår i: Materials & Design. - 0261-3069. ; 24:7, s. 519-529
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Tidskriftsartikel (refereegranskat)abstract
- There are many things that make products successful in the market place. This paper is a comprehensive tool for understanding how to develop products with special respect to integrated product development. Materials selection, marketing and design analysis in the form of a design manual are presented as a tool for the product developer. Many different methods for materials selection and design have been presented over the last couple of decades. However, most methods have been limited to the material as a physical entity to give shape for a product. The method presented in this paper is an approach to present a materials selection model that is an integral part in an integrated product development model, in which both physical and metaphysical properties are analysed for different types of products. The new integrated product materials selection (IPMS) model presented incorporates factors such as fashion, market trends, cultural aspects, aesthetics and recycling, as well as the target group. Interesting examples of successful product contra failures are presented, as well as examples of materials selection for different products. Different methods for materials selection are discussed and analysed with respect to the IPMS method presented.
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| 4. |
- Alam, Md. Minhaj, et al.
(författare)
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Analysis of the stress raising action of flaws in laser clad deposits
- 2013
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Ingår i: Materials and Design. - : Elsevier BV. - 0261-3069 .- 0264-1275 .- 1873-4197. ; 46, s. 328-337
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Tidskriftsartikel (refereegranskat)abstract
- Fatigue cracking of laser clad cylindrical and square section bars depends upon a variety of factors. This paper presents Finite Element Analysis (FEA) of the different macro stress fields generated as well as stress raisers created by laser cladding defects for four different fatigue load conditions. As important as the defect types are their locations and orientations, categorized into zero-, one- and two-dimensional defects. Pores and inclusions become critical close to surfaces. The performance of as-clad surfaces can be governed by the sharpness of surface notches and planar defects like hot cracks or lack-of-fusion (LOF) are most critical if oriented vertically, transverse to the bar axis. The combination of the macro stress field with the defect type and its position and orientation determines whether it is the most critical stress raiser. Based on calculated cases, quantitative and qualitative charts were developed as guidelines to visualize the trends of different combinations.
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| 5. |
- Alam, Md. Minhaj, et al.
(författare)
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Generalising fatigue stress analysis of different laser weld geometries
- 2011
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Ingår i: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197 .- 0261-3069. ; 32:4, s. 1814-1823
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional elastic-plastic finite element analyses was carried out on a laser welded box beam in order to study the impact of the geometrical aspects of the joint type and weld root on the fatigue stress behaviour. Different experimental and hypothetical weld geometries were studied. Characteristic root shapes, measured by the plastic replica method, and critical geometrical aspects were classified and then studied by FE-analysis with respect to their impact on the maximum stress. The simulation of hypothetical transition geometries facilitated the identification of trends and the explanation of part of the phenomena. However, quantitative geometry criteria were only partially suitable to describe the relations. The results have shown that the combination of throat depth, local surface radius and its opening angle determines the peak stress value and its location. Beside extended throat depths, particularly larger toe radii and the avoidance of small opening angles and of surface ripples reduces the peak stress. The explanations were developed in a generalising manner, accompanied by illustrative and flow chart description.
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| 6. |
- Alimadadi, Hossein, 1983, et al.
(författare)
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Corrosion properties of electrodeposited nanocrystalline and amorphous patterned Ni-W alloy
- 2009
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Ingår i: MATERIALS & DESIGN. - : Elsevier BV. - 0261-3069 .- 0264-1275 .- 1873-4197. ; 30:4, s. 1356-1361
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Tidskriftsartikel (refereegranskat)abstract
- Nickel-tungsten with satisfactory corrosion properties is a promising alloy to replace hard chromium. Relatively high adhesion between copper substrate and electrodeposited Ni-W alloy results in patterned morphology due to crack formation. In this work, corrosion resistance of patterned Ni-W alloys comprising 0-26 at.%.W were studied by potentiodynamic polarization and EIS in a medium containing Cl-. It is shown that corrosion resistance of single phase Ni-W is superior to amorphous and dual phase coated layers. It is also found that crack density is the dominant affecting factor on corrosion resistance of amorphous Ni-W alloys.
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| 7. |
- Aziz, Shazed, et al.
(författare)
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Effect of fibre coating and geometry on the tensile properties of hybrid carbon nanotube coated carbon fibre reinforced composite
- 2014
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Ingår i: Materials & Design. - : Elsevier. - 0261-3069. ; 54, s. 660-669
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Tidskriftsartikel (refereegranskat)abstract
- Hierarchically structured hybrid composites are ideal engineered materials to carry loads and stresses due to their high in-plane specific mechanical properties. Growing carbon nanotubes (CNTs) on the surface of high performance carbon fibres (CFs) provides a means to tailor the mechanical properties of the fibre–resin interface of a composite. The growth of CNT on CF was conducted via floating catalyst chemical vapor deposition (CVD). The mechanical properties of the resultant fibres, carbon nanotube (CNT) density and alignment morphology were shown to depend on the CNT growth temperature, growth time, carrier gas flow rate, catalyst amount, and atmospheric conditions within the CVD chamber. Carbon nanotube coated carbon fibre reinforced polypropylene (CNT-CF/PP) composites were fabricated and characterized. A combination of Halpin–Tsai equations, Voigt–Reuss model, rule of mixture and Krenchel approach were used in hierarchy to predict the mechanical properties of randomly oriented short fibre reinforced composite. A fractographic analysis was carried out in which the fibre orientation distribution has been analyzed on the composite fracture surfaces with Scanning Electron Microscope (SEM) and image processing software. Finally, the discrepancies between the predicted and experimental values are explained.
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| 8. |
- Barsoum, I., et al.
(författare)
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Analysis of the torsional strength of hardened splined shafts
- 2014
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Ingår i: Materials and Design. - : Elsevier BV. - 0261-3069. ; 54, s. 130-136
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Tidskriftsartikel (refereegranskat)abstract
- The current study presents a finite element modeling framework to determine the torsion strength of hardened splined shafts by taking into account the detailed geometry of the involute spline and the material gradation due to the hardness profile. The aim is to select a spline geometry and hardness depth that optimizes the static torsion strength. Six different spline geometries and seven different hardness profiles including non-hardened and through-hardened shafts have been considered. The results reveal that the torque causing yielding of induction hardened splined shafts is strongly dependent on the hardness depth and the geometry of the spline teeth. The results from the model agree well with experimental results found in the literature and reveal that an optimum hardness depth maximizing the torsional strength can be achieved if shafts are hardened to half their radius.
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| 9. |
- Barsoum, Zuheir, et al.
(författare)
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Fatigue strength evaluation of friction stir welded aluminium joints using the nominal and notch stress concepts
- 2012
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Ingår i: Materials & Design. - : Elsevier BV. - 0261-3069. ; 41, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- In this study the fatigue strength is investigated for Friction Stir Welded (FSW) overlap and butt welded joints in different thicknesses based on nominal and effective notch stress concepts. The fatigue test results are compared with fatigue strength recommendations according to EN 1999-1-3 and International Institute of Welding (IIW). The results are also compared with available published data and Finite Element Analysis (FEA) is carried out to investigate the effect of plate thickness and nugget size on the fatigue strength of overlap joints. 3-3 mm butt welded joints shows the highest fatigue strength in comparison with 3-5 mm butt welded and overlap joints. Slopes of the SN-curves for two different joint types differ from the slope recommended by IIW. A specific failure trend is observed in overlap FSW joints. However, the slopes of the SN-curves are in close agreement with slopes found in EN 1999-1-3. The slopes of various published results and test results presented in this study are in good agreement with each other. The suggested fatigue design curves for the nominal and effective notch stress concept have a higher slope than given for fusion welds by IIW.
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| 10. |
- Bhatti, Ayjwat A., et al.
(författare)
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Influence of thermo-mechanical material properties of different steel grades on welding residual stresses and angular distortion
- 2015
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Ingår i: Materials & Design. - : Elsevier BV. - 0261-3069. ; 65, s. 878-889
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates the influence of thermo-mechanical material properties of different steel grades (S355-S960) on welding residual stresses and angular distortion in T-fillet joints. Different cases in which temperature dependent thermo-mechanical material properties are considered as constant, linear, and as a function of temperature are simulated by using finite element (FE) method. Experiments are carried out to evaluate temperature dependent yield stress and Young's modulus for S700 and S960 steel grades. Furthermore, JMat Pro software is used to obtain the remaining thermo-mechanical material properties. The numerical predictions of angular distortion and transverse residual stresses are validated with experimental measurements. It is observed that for assessment of residual stresses, except yield stress, all of the thermo-mechanical properties can be considered as constant. For the prediction of angular distortions with acceptable accuracy, heat capacity, yield stress and thermal expansion should be employed as temperature dependent in the welding simulations.
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