Search results for "RILL"

An analysis of through-thickness residual stresses in aluminium FSW butt joints

2006

Abstract In the paper, the results of a wide experimental campaign on friction stir welding (FSW) of aluminum alloys are reported. The attention was focused on the through-thickness residual stresses that occur on aluminum joints, after the welding process. In detail, using the hole-drilling method the residual stresses distribution in the zone close to the tool shoulder border of the joint advancing side, has been investigated; four different aluminum alloys and three different process conditions have been considered. The experimental analysis has shown that unlike traditional welding processes, the residual stresses are negative in the surface of the examined zone, and increase with depth…

Measurement of residual stresses by the hole-drilling method: General stress-strain relationship and its solution

1990

RESIDUAL STRESS ANALYSIS OF ORTHOTROPIC MATERIALS BY THE THROUGH-HOLE DRILLING METHOD

2007

The present study deals with the development and the application of the through-hole drilling method for the residual stress analysis in orthotropic materials. Through a systematic theoretical study of the stress field present on orthotropic plates with a circular hole, the relationships between the relaxed strains measured by a rectangular strain gauge rosette and the Cartesian components of the unknown residual stresses are obtained. The theoretical formulas of each influence coefficient allow the user an easy application of the method to the analysis of uniform-residual stresses on a generic homogeneous orthotropic material. Furthermore, to extend the method to the analysis of the residu…

Optimal calculation steps for the evaluation of residual stress by the incremental hole-drilling method

1999

The integral method is a suitable calculation procedure for the determination of nonuniform residual stresses by semidestructive mechanical methods such as the hole-drilling method and the ring-core method. However, the high sensitivity to strain measurement errors due to the ill conditioning of the equations has hindered its practical use. the analysis of the influence of the strain measurment error on the computed stresses carried out in the present work has showed that, given both maximum hole depth and number of total steps, the error sensitivity depends on the particular depth increment distribution used. By means of the matrix formulation, the depth increment distribution that optimiz…

Solemne acte d'investidura com a doctor 'Honoris Causa' del Sr. Manuel Elkin Patarroyo Murillo

1997

Solemne acte d'investidura com a Dr. Honoris Causa de l'excel·lentíssim Sr. Manuel Elkin Patarroyo Murillo en el paranimf de la Universitat de València.

Analysis of rill step–pool morphology and its comparison with stream case

2021

In this paper, the morphology of step–pool features is analysed using rill measurements and literature data for streams. Close-range photogrammetry was used to carry out ground measurements on rills with step–pool units, shaped on a plot having slope equal to 14, 15, 22, 24 and 26%. Data were used to compare the relationships between H/L, in which H is the step height and L is the step length, and the mean gradient of the step–pool sequence, Sm, for streams or the slope of the step–pool unit, S, for rills. The relationship of H/L against Sm is widely used to test the occurrence of the maximum flow resistance condition in streams, which is associated with the range 1 ≤ (H/L)/Sm ≤ 2. Further …

Analysis of soil loss data from plots of differing length for the Sparacia experimental area, Sicily, Italy

2010

Widely used models of the soil erosion process, such as the empirical universal soil loss equation (USLE) and revised USLE (RUSLE), suggest that soil loss, i.e. the mass of soil lost by water erosion per unit surface area, increases with slope length, λ, although contrasting experimental results may be found in the literature. Experiments were carried out at the Sparacia site, Sicily, to establish the influence of plot length on soil loss. This was tested using data characterised by a high number of replicated, bare plots of different lengths (0.25, 0.4, 1, 2, 5, 11, 22, 33 and 44 m), simultaneously operating in the 1999–2008 period. Event soil losses did not vary significantly with λ or ev…

Establishing a soil loss threshold for limiting rilling

2015

In this paper a frequency analysis of event soil loss measurements collected in the period 1999–2012 at the microplots and plots of the Sparacia Experimental Area in Sicily, southern Italy, was developed. The analysis was carried out using the annual maximum soil loss measurements normalized by the mean soil loss measured at a given temporal and spatial scale. The empirical frequency distribution of the normalized variable was well fitted by two Gumbel’s theoretical probability distributions discriminated by a value of the normalized variable equal to 2. This last value discriminates between the relatively low and frequent values of the normalized variable and the high and rare ones. The an…

Concise review of interrill erosion studies in SE Spain (Alicante and Murcia): erosion rates and progress of knowledge from the 1980s

2005

From the 1980s onward studies on interrill soil erosion were intensified in SE Spain. The main achievements of the research carried out in the field areas of Alicante and Murcia concern: first, (1) the estimation of erosion rates directly in the field under a wide range of methodologies, different scales and different environmental conditions; (2) estimations based on existing models, such as the USLE, carried out for different subcatchments of the Segura and Júcar catchments; and (3) other parametric and physical event-based models have also been calibrated and validated. Second, the progress of the knowledge in understanding erosion mechanisms. New and reviewed concepts regarding mainly h…

MORPHOLOGY AND DEVELOPMENT OF SELECTED BADLANDS IN SOUTHEAST SPAIN: IMPLICATIONS OF CLIMATIC CHANGE

1996

Four areas were selected to represent a range of processes characteristic of badland surfaces in southeast Spain: Petrer and Monnegre in Alicante, Vera and Tabernas in Almeria. At Petrer, rilling and swelling processes produce a deeply cracked surface drained by a finely textured network of shallow rills. At Monnegre, piping and rilling are differentially developed on slopes ultimately controlled by basal incision. At Vera, aspect-controlled lichen and vegetation cover produce a sequence of badland development within which the relative importance of piping, mass movement and rilling varies through the sequence. At Tabernas, simple overland flow is the dominant process, but aspect influences…