South African Indian English: a qualitative study of attitudes

This paper focuses on attitudes towards South African Indian English (SAIE), an L1 variety of English spoken in South Africa. The attitudes of the participants are considered against the backdrop of the socio-political history of this variety and its speakers, and in contrast to their attitudes to what they perceive as 'good' English. While the research methodology is primarily based on lengthy, semi-structured interviews with twenty young South African Indians (i.e. in-group members), the paper also includes a discussion of some of the linguistic features of SAIE, which is mainly motivated by methodological considerations. Through an examination of SAIE wh-questions, we show that the grammar of this variety differs systematically from that of the reference variety. Using examples of these wh-questions, we elicited grammatical judgments from participants and compared these judgments to the attitudes of the participants as expressed in response to open-ended questions in interviews. On the basis of the empirical data that we obtained and analysed, we argue that the young South African Indian students who participated in our study have a profoundly ambiguous attitude towards the variety associated with their own ethno-linguistic group.

Numerical and experimental validation of residual stresses of laser-welded joints and their influence on the fatigue behaviour

In this work laser-welded tube-tube specimens made of aluminium alloys AlMg3.5Mn and AlSi1MgMn T6 were experimentally tested under constant and variable amplitude loading, under pure axial and pure torsion loading. In order to evaluate the influence on fatigue behaviour of the residual stresses, because of the welding process, some specimens were subjected to postweld heat treatment and then were tested. The numerical analyses, using finite element (FE), were carried out to obtain a reliable estimation of the residual stress in the specimen. The numerical results were in a good agreement with experimental ones obtained by means of hole-drilling method. Finally, the residual stress distribution was superimposed to stress distribution because of fatigue loads obtained by FE analyses applying local concept, to calculate the stresses in the crack initiation zone and to understand the different types of failure that occurred in as-welded and relieved specimens

Comparison of predictions by mode II or mode III criteria on crack front twisting in three or four point bending experiments

International audienceWhatever the external loading, a crack front in a solid tries to reach mode I loading conditions after propagation. In mode I+II, the crack kinks to annihilate mode II, kinking angle being well predicted by the principle of local symmetry (PLS) or by the maximum tangential stress criterion (MTS). In presence of mode III, the problem becomes three-dimensional and the proposed propagation criterion are not yet well proved and established. In particular in three point bending experiments (3PB) with an initially inclined crack, the crack twists around the direction of propagation to finally reach a situation of pure mode I. The aim of the paper is to compare the propagation paths predicted by two different criteria for 3PB fatigue experiments performed on PMMA. The first criterion developed by Schollmann et al (2002), is a three-dimensional extension of the MTS criterion and predicts the local angles that annihilates mode II and III at each point of the front. The second one developed by Lazarus et al (2001b), predicts an abrupt and then progressive twisting of the front to annihilate mode III. Due to presence of sign changing mode II and almost uniform mode III in the experiments, both criteria give good results. However , since mode III is predominant over mode II in the case under consideration, the global criterion gives better results. Nevertheless, the local type criterion seems to be of greater universality for practical engineering applications

Fatigue life assessment of welded joints under sequences of bending and torsion loading blocks of different lengths

In this work, the nominal stress concept, the notch stress approach and two critical plane approaches are used to analyse the fatigue endurance of a pipe-to-plate welded joint subjected to complex loading histories. Both the pipe and the plate were made of S355JR steel. Starting from already known fatigue endurance curves obtained for the same specimens under pure bending and pure torsion, a first series of tests was conducted, in which specimens were loaded in bending for a given fraction of the estimated life and then in torsion until failure. A similar series of tests was then carried out by changing the loading order: specimens were firstly loaded in torsion for a given fraction of the estimated endurance and then in bending until failure. The whole test campaign was repeated for two different fractions of the estimated life, that is, 0.3 and 0.45, respectively. After that, additional three series of tests were carried out, in which the specimens were subjected to consecutive sequences of bending and torsion blocks of different lengths (short, medium and long, respectively); the relative length of the bending and torsion block in each series was determined in order to produce the same damage. The experimental results, in terms of total damage at failure, were analysed using the Palmgren–Miner hypothesis. For all the assessment methods, the characteristic endurance curves were firstly calibrated on the basis of finite element (FE) analyses and of the experimental results obtained under pure bending and pure torsion loadings. The observed damage at failure resulted always greater than 0.5 for all the employed methods and greater than 1 for most of the tests. The different methods gave similar results, with the critical plane methods giving a slightly more stable damage at failure and a correct determination of the failure location. For all the methods, the damage at failure slightly reduces as the block length shortens