Aida Nonn

• PhD
• Professor (Full) at OTH Regensburg, Regensburg, Germany

The aim of this paper is to present practical steps for utilizing a validated multiphysics approach for fracture control in CO2 pipelines within the framework of Carbon Capture Transport and Storage (CCTS). Ensuring the arrest of running ductile fracture (RDF) is a crucial safety requirement for the transportation of dense-phase CO2. However, curre...

Data-driven models are developed to predict the mechanical properties of polycrystalline materials. The case study is the prediction of the yield strength of a 3D-printed 316L steel from morphological and crystallographic features. Three different artificial intelligence models including feed-forward (FNN), convolution (CNN), and graph (GNN) neural...

Customized additively manufactured (laser powder bed fused (L-PBF)) stents could improve the treatment of complex lesions by enhancing stent-artery conformity. However, geometric irregularities inherent for L-PBF stents are expected to influence not only their mechanical behavior but also their interaction with the artery. In this study, the influe...

The current analyses present results of running ductile fracture propagation in high strength X100 line pipe steels under the influence of anisotropy. Mechanical anisotropy is commonly available in pipe products as a result of the manufacturing process, especially, those subjected to hot/cold-worked deformation. The outcomes of the present analyzes...

Abrasive wear limits the lifetime of many machine components. Most empirical models relate the abrasive wear resistance to material hardness. In reality, however, other material properties are also influencing as scratch abrasion damage follows from a highly complex stress trajectory upon scratching. Numerical (finite element) simulation of scratch...

Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed...

Experimental investigations are conducted to quantify the influence of specimen thickness and orientation on the mechanical properties of selective laser melted stainless steel 316 L. The results indicate that the mechanical strength and ductility increase with increasing specimen thickness until a saturation value is reached from a specimen thickn...

A comprehensive experimental program is carried out to determine material parameters for fracture initiation and propagation in X100 pipeline steels. The quadratic Hill’48 yield function along with an isotropic hardening are used to describe plastic flow at large deformation and a phenomenological fracture criterion to predict fracture initiation....

The fracture propagation and arrest control for pipelines transporting rich natural gases and high vapor pressure liquids is based on the Battelle Two-Curve Model (BTCM). Distinct limitations of this model were demonstrated for past and modern steels and gas mixtures. These can be related to the insufficient description of individual physical proce...

In-stent restenosis remains a major problem of arteriosclerosis treatment by stenting. Expansion-optimized stents could reduce this problem. With numerical simulations, stent designs/ expansion behaviours can be effectively analyzed. For reasons of efficiency, simplified models of balloon-expandable stents are often used, but their accuracy must be...

This paper explores the efficacy of employing local damage models, normally applied to ductile material systems manufactured by subtractive techniques, to additively manufactured laboratory specimens. While these specimens were ductile and metallic, their additive character (i.e. porosity and surface roughness) could have had potential to activate...

As part of current design standards, the Battelle Two-Curve Model (BTCM) is still widely used to predict and secure ductile crack arrest in gas transmission pipelines. For modern linepipe steels and rich natural gases or CO2 mixtures, the BTCM might lead to incorrect predictions. On the one hand, it suffers from the insufficient description of the...

The Sandia Fracture Challenges provide a forum for the mechanics community to assess its ability to predict ductile fracture through a blind, round-robin format where mechanicians are challenged to predict the deformation and failure of an arbitrary geometry given experimental calibration data. The Third Challenge (SFC3) required participants to pr...

The complex mechanical and corrosive loads of modern pipeline systems transporting oil, natural gas and CO 2 impose steadily increasing requirements on material properties. The majority of current design standards still limit the application of modern high toughness linepipe steels due to the simple specification of material requirements in terms o...

Various numerical approaches have been developed in the last years aimed to simulate the ductile fracture propagation in pipelines transporting CO2 or natural gas. However, a reliable quantification of the influence of material plasticity on the fracture resistance is still missing. Therefore, more accurate description of the material plasticity on...

Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the bli...

An over-the-counter methodology to predict fracture initiation and propagation in the challenge specimen of the Second Sandia Fracture Challenge is detailed herein. This pragmatic approach mimics that of an engineer subjected to real-world time constraints and unquantified uncertainty. First, during the blind prediction phase of the challenge, flow...

The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10mm different Charpy standards allow for the application of sub-sized specimens. However, it is still not fully c...

Fracture propagation control in gas transmission gas pipelines belongs to the major design requirements for safe operation at high internal pressures. However, the current tests such as Drop-Weight-Tear Test (DWTT) and full-scale West- Jefferson (WJ) test reach the limits of their applicability with respect to transition temperature evaluation for...

Investigation of running ductile fracture in gas transmission pipelines and the derivation of reliable crack arrest prediction methods belong to major topics in pipeline research. The yet available crack arrest criterion, known as the Battelle Two-Curve Method (BTCM), leads to reliable predictions up to grade X70 line pipe steels for which it has b...

The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pi...

The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pi...

The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10 mm different standards allow for the application of sub-sized specimens and different empirical correlations be...

The Park-Paulino-Roesler (PPR) potential-based model is a cohesive constitutive model formulated to be thermodynamically consistent under a high degree of mode-mixity. Herein, the PPR’s generalization to three-dimensions is detailed, its implementation in a finite element framework is discussed, and its use in single-core and high performance compu...

The determination of the exact mechanical properties of material is essential for an optimal and safe design of linepipes. It is especially important for the prevention of over-engineering and the reliable assessment of complex accidental loading, such as extreme bending due to loss of buoyancy of support, or abrupt ground movement. Currently, the...

Fracture behavior of seamless pipeline material X65Q acc. to API 5L has been studied both experimentally and numerically at different loading conditions (quasi-static vs. dynamic) and temperatures. The recent findings have shown difficulties in applying well established methods for determination of transition behavior or prediction of ductile crack...

The performance of engineering design of high-strength steel pipelines has revealed the necessity to revise current design procedures. Therefore, an improved and detailed comprehension of fracture mechanisms and development of failure prediction tools are required in order to derive new design criteria. In last decades the most successful failure p...

This paper provides results from a comprehensive study on mechanical characterization of high-strength pipeline steel, grade X100 using experimental and numerical methods. The material was characterized for anisotropic plasticity, fracture initiation for various states of stress, (pre-cracked) fracture toughness and uncracked ductility. The experim...

This paper focuses on the characterization of the fracture performance of X100 material in transition temperature region using both experimental and numerical methods. The ductile fracture has been analyzed using tests on round notched bar specimens and standard fracture mechanics tests performed at room temperature. In previous publications the da...

1 Salzgitter Mannesmann Forschung GmbH, Ehinger Straße 200, 47259 Duisburg, Germany 2 EUROPIPE, Pilgerstr. 2, 45473 Mülheim an der Ruhr, Germany ABSTRACT The worldwide growing importance of oil and gas transport has led to increasing application of high strength steels, e.g. X100, for pipelines. Although the development of the new high-strength ste...

The present paper deals with the influence of heat affected zone (henceforth HAZon the fracture performance of longitudinal welded linepipes in dependence on constraint level. It has been shown that toughness values of HAZ obtained from standard fracture mechanics tests lead to uneconomic linepipe design for two reasons. The first reason is that la...

Plastic design allows the exploitation of the full resistance of steel structures by taking advantage of stress–redistributions due to plastic strains exceeding the yield strain. Especially in seismic design the utilization of material reserves and the formation of plastic hinges play an important role. In devastating earthquakes in Northridge (USA...

Das Hybridlaserschweißverfahren, das Laserstrahl- und Lichtbogenschweißen miteinander kombiniert, wird dank vieler Vorteile, die aus beiden Schweißprozessen resultieren, in verschiedenen industriellen Bereichen zunehmend eingesetzt. Mit der Erweiterung der Anwendungsgebiete steigt auch der Bedarf nach genauer Kenntnis der mechanischen Eigenschaften...

The effect of laser-hybrid welds on deformation and failure behaviour of fracture mechanics specimens is investigated in order to provide quantitative prediction of damage tolerance and residual strength. The simulation of crack initiation and crack extension in hybrid welds is performed by applying GTN damage model. The identification of damage pa...