Procedia structural integrity
About: Procedia structural integrity is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Materials science & Fracture mechanics. It has an ISSN identifier of 2452-3216. It is also open access. Over the lifetime, 3956 publications have been published receiving 16693 citations.
Topics: Materials science, Fracture mechanics, Structural engineering, Finite element method, Fatigue limit
TL;DR: In this article, a review about non-destructive testing (NDT) methods for the evaluation of composites is provided, considering the capabilities of most common methods in composite NDT applications such as Visual Testing (VT or VI), Ultrasonic Testing (UT), Thermography, Radiographic Testing (RT), Electromagnetic Testing (ET), Acoustic Emission (AE), and Shearography Testing with respect to advantages and disadvantages of these methods.
Abstract: A review provided about non-destructive testing (NDT) methods for the evaluation of composites. The review considers the capabilities of most common methods in composite NDT applications such as Visual Testing (VT or VI), Ultrasonic Testing (UT), Thermography, Radiographic Testing (RT), Electromagnetic Testing (ET), Acoustic Emission (AE), and Shearography Testing with respect to advantages and disadvantages of these methods. Then, methods categorized based on their intrinsic characteristics and their applications.
TL;DR: In this article, an aircraft bracket topology was optimised to be produced by means of additive manufacturing (AM) and a design methodology was defined in order to facilitate and make more accurate the TO solution design.
Abstract: Additive Manufacturing (AM) is a manufacturing process through which a 3D component is produced by consecutively adding material. One of the most promising AM processes is SLM. In SLM a laser completely melts metallic powder particles together forming a 3D component. SLM is known for its freedom of manufacturing constraints allowing complex geometries and high material efficiency. Topology Optimisation (TO) is an optimisation type that calculates the optimal material distribution for a given problem. The combination of SLM with TO is being developed to create lightweight components. In this work, the whole development process, from optimisation to design, production and testing is addressed. Initially, an aircraft bracket topology was optimised to be produced by means of SLM. The TO solution was interpreted and designed for AM. During the interpretation and design process, a design methodology was defined in order to facilitate and make more accurate the TO solution design and make it ready for AM. After the optimised component was produced, metrological and mechanical tests were performed in order to validate the final design and the computer analysis. The optimised component showed considerable weight reduction with an increase of the factor of safety. The experimental tests revealed a good relation to the computer analysis evidencing, however, room for improvement, both in the computer model and the experimental tests.
TL;DR: In this article, the effects of defects, surface roughness and Hot Isostatic Pressing (HIP) process on the fatigue strength of a Ti-6Al-4V manufactured by AM was investigated.
Abstract: The additive manufacturing (AM) is expected to be the promising manufacturing process for high strength or hard steels such as Ti-6Al-4V for the aerospace industry components having complex shapes. However, disadvantage or challenge of AM is presence of defects which are inevitably contained in the manufacturing process. This paper focuses on the effects of defects, surface roughness and Hot Isostatic Pressing (HIP) process on the fatigue strength of a Ti-6Al-4V manufactured by AM. The guide is presented for the fatigue design and development of high quality and high strength Ti-6Al-4V by AM processing based on the combination of the statistics of extremes on defects and the √area parameter model. Defects were mostly gas porosity and those made by lack of fusion. Many pores which were formed near surface were eliminated by HIP and eventually HIP improved fatigue strength drastically to the level of the ideal fatigue limit to be expected from the hardness. Surface roughness had strong detrimental influence on fatigue strength. The method for estimating the effective size √areaeffmax of irregularly shaped defects and interacting adjacent defects was proposed from the viewpoint of fracture mechanics. Although the statistics of extremes analysis is useful for the quality control of AM, the particular surface effect and interaction effect of adjacent defects must be carefully considered. The effective defect size for adjacent defects is much larger than a single defect. Since the orientations of defects in AM materials are random, a defect in contact with specimen surface has a higher influence (termed as the effective defect size √areaeff) than the real size of the defect from the viewpoint of fracture mechanics. Considering the volume and number of productions of components, the lower bound of the fatigue limit σwl based on √areaeffmax can be determined by the √area parameter model.
TL;DR: The preliminary results presented in this work reveal the crucial parameters that affect the value of the shear strength of reinforced concrete beams with or without transverse reinforcement.
Abstract: Despite the abundance of research works, both experimental and theoretical, conducted since the middle of the previous century up to today, the determination of the shear stress value is still remains an open issue of great interest in structural engineering. The need for further research is indicated by the fact that the majority of available proposals, whether proposed by regulatory agencies or various individuals researchers, lead to the estimation of different shear stress values; moreover, the comparison of estimated values with experimental values demonstrates that the available proposals lead to an overestimation or to an underestimation of the “true” shear stress. In this research study, the artificial neural networks approach is used to estimate the ultimate shear capacity of reinforced concrete beams with transverse reinforcement. More specifically, artificial neural network models have been examined for predicting the shear capacity of concrete beams, based on experimental test results available in the pertinent literature. The comparison of the consequent results with the corresponding experimental ones as well as with available formulas from previous research studies or code provisions makes obvious the ability of artificial neural networks to evaluate the shear capacity of reinforced concrete beams in a trustworthy and effective manner. Furthermore, the preliminary results presented in this work reveal the crucial parameters that affect the value of the shear strength of reinforced concrete beams with or without transverse reinforcement.
TL;DR: In this paper, a comparative Life Cycle Assessment of Internal Combustion Engine (ICE) and electric vehicles is presented, which follows a "from cradle-to-grave" approach and it captures the whole Life Cycle (LC) of the car subdivided into production, use and end-of-life stages.
Abstract: Transportation represents one of the major contributors to several environmental burdens such as Green-House-Gas (GHG) emissions and resource depletion. Considering the European Union, light duty vehicles are responsible for roughly 10% of total energy use and air emissions. As a consequence, the need for higher fuel/energy efficiency in both conventional and electric cars has become urgent and the efforts across industrial and research players have proposed a range of innovative solutions with great potential. This study presents a comparative Life Cycle Assessment of Internal Combustion Engine (ICE) and electric vehicles. The analysis follows a “from cradle-to-grave” approach and it captures the whole Life-Cycle (LC) of the car subdivided into production, use and End-of-Life stages. The inventory is mainly based on primary data and the assessment takes into account a wide range of impact categories to both human and eco-system health. The eco-profile of the different vehicle configurations is assessed and the main environmental hotspots affecting conventional and electric cars are identified and critically discussed. The dependence of impacts on LC mileage is investigated for both propulsion technologies and the break-even point for the effective environmental convenience of electric car is determined considering several use phase electricity sources. The analysis is completed with a comparison of GHG emissions with the results of previous LCA studies.