W. Brocks¹, I. Scheider²

Structural Durability & Health Monitoring, Vol.6, No.3&4, pp. 189-212, 2010, DOI:10.3970/sdhm.2010.006.189

Abstract Material parameters are adjustable coefficients in constitutive equations of the mechanical behaviour. Their identification requires a combined experimental and numerical approach, which results in a generally ill-posed inverse problem. Methods commonly applied in computational mechanics like optimisation and neural networks are addressed, and problems like sensitivity, uniqueness and stability are discussed. The cohesive model for describing ductile tearing is chosen as practical example to substantiate the general considerations. More >

H.A. Richard¹, M. Fulland², G. Kullmer¹, N.-H. Schirmeisen¹

Structural Durability & Health Monitoring, Vol.6, No.3&4, pp. 161-188, 2010, DOI:10.3970/sdhm.2010.006.161

Abstract Fracture processes in real structures are in many cases of a three dimensional (3D) character. In this paper some basic problems of 3D-fracture processes are considered and discussed, in particular for general mixed-mode loading conditions, when modes I and II and III are superimposed. For experimental investigations an AFM-specimen is under consideration, while numerical simulations are carried out with the program ADAPCRACK3D. More >

R. G. Cuntze¹

Structural Durability & Health Monitoring, Vol.6, No.3&4, pp. 123-160, 2010, DOI:10.3970/sdhm.2010.006.123

Abstract The paper deals with the validation of 2D and 3D failure conditions of unidirectional (UD) composites composed of endless fibres and thermoset matrices. The generation of these failure conditions is shortly described and then applied to test cases of the World-Wide-Failure-Exercises WWFE-I and II, organized by Qinetic in the past 20 years. The derivation of the conditions for the brittle fracture failure experiencing UD lamina material was based on the author's so-called Failure Mode Concept (FMC) which basically builds up on the hypotheses of Beltrami and Mohr-Coulomb. The generally applicable FMC is applied here to… More >

S. Hadidi-Moud^1,2, H. Makari¹

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 113-122, 2010, DOI:10.3970/sdhm.2010.006.113

Abstract A comprehensive numerical study has been carried out to investigate and to explore the impact of the presence of part through surface cracks of various size and orientation in a thick welded ferritic steel cylindrical vessel, on the beneficial effect of autofrettage loading. It is well known that autofrettage loading enhances the load carrying capacity of defect free pressure vessels. The results of this study suggest that in presence of cracks, the localised near crack tip residual stress fields interact with in service stresses and influence the enhancement in load carrying capacity of autofrettaged vessel. More >

Zihua Zhao¹, Yu Zhou, Zheng Zhang, Qunpeng Zhong

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 101-112, 2010, DOI:10.3970/sdhm.2010.006.101

Abstract Annex H"Safety assessment method for straight pressure pipeline with local thinning area" of "Safety assessment for in-service pressure vessels containing defects"(GB/T 19426-2004) is briefly introduced. The maximum allowable hanging (unsupported) length of straight pressure pipeline with a local thinning area (LTA) is then determined by using this assessment method. This is the first time that the assessment method has been applied to the long-distance oil pipeline. As a typical case, we have analyzed a length of straight pressure pipeline with LTA and gave the relationship of maximum allowable unsupported length, operating pressure and the depth More >

Fausto Pedro García Márquez¹

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 89-100, 2010, DOI:10.3970/sdhm.2010.006.089

Abstract This paper presents a simple graphic method for detecting and classifying faults in point mechanisms based on the study of some statistical parameters of the force and current signals of the point machine. Principal Components Analysis (PCA) employed in order to reduce the number of these parameters. PCA is utilised in this paper for modifying the parameter dataset, and reducing the coordinate system by linear transformation. It is then possible to plot the new coordinate system in 2 or 3 dimensions, where the faults can be detected and identified. In this work most of the More >

Xue-Ren Wu¹

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 77-88, 2010, DOI:10.3970/sdhm.2010.006.077

Abstract A review of the state-of-the-art is presented on the weight function method for fracture-mechanics-based structural integrity assessment with regard to crack-like defects. The weight function method provides a powerful tool for the determination of key parameters, such as stress intensity factors and crack opening displacements for cracked structural components. For two dimensional (2D) crack problems, weight functions were obtained in closed-form for both centre-and edge-crack configurations. For three dimensional(3D) cases, a combination of the closed-form 2D weight functions and the slice synthesis technique makes it possible for rapid determination of stress intensity factor at any More >

Mark Pompetzki¹, Brian Dabell¹, Xiaobin Lin²

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 69-76, 2010, DOI:10.3970/sdhm.2010.006.069

Abstract Structural integrity in terms of automotive durability is a detailed process that incorporates many technical areas. The current durability process for automotive applications involves understanding operational load inputs, the stresses and strains caused and the response of the material, performing fatigue tests, calculating fatigue life and interpreting results. There are many variations on this process depending on the application, materials, available information, methods, etc. This paper presents a general approach for the durability process in automotive applications and highlights a number of new advancements. These advancements include understanding the service operating load conditions through improved More >

Muddasar Khan¹, Cesar Levy¹, Amer Hameed¹, Zulfiqar Khan¹, Khalid Orakzai¹, Musarrat Khan¹, Khuram Shahazad¹, Afzaal M.Malik¹, Shahab Khushnood¹

Structural Durability & Health Monitoring, Vol.6, No.2, pp. 53-68, 2010, DOI:10.3970/sdhm.2010.006.053

Abstract Aluminum metal beverage container is used in packaging foods and chemical industries because of its superior hold, formability, corrosion resistance and join ability. The 80 percent of the container cost is material and aluminum metal is expansive one. The beverage container industry is struggling for potential saving from weight reduction in each container, while meeting the three structural performance standards which have been established to assess the adequacy of the container design. These are axial column load, drop resistance and internal pressure. This paper relates to the internal pressure standard which states that container must… More >

I. Černý^1,2, D. Mikulová¹

Structural Durability & Health Monitoring, Vol.6, No.1, pp. 43-52, 2010, DOI:10.3970/sdhm.2010.006.043

Abstract Alternative methods of material machining like electro-erosive or water jet cutting, respectively, represent modern technologies, which are perspective to be used as final end-to-shape operations due to their possibilities of automatization and cutting precision. The paper contains results of an investigation of resistance of an aircraft AISI 4340 steel against fatigue loading performed using specimens loaded by three point bending at ambient temperature and standard laboratory conditions. Results of fatigue tests of specimens with surface after electro-erosive and water jet cutting, respectively, are presented, whereas in the latter case, areas of water jet incidence and… More >