In reality most welded components are loaded with a combination of different variable forces and moments that often cause a state of multiaxial stress in the fatigue‐critical areas. If the multiaxial loading is non‐proportional, traditional deformation‐based hypotheses are not able to give a reliable lifetime prediction. This investigation is a cooperation between three German research institutes to build an experimental database for the verification of different concepts of lifetime prediction. In accordance with former investigations, a flange‐tube connection made of steel P460 was used. The test program was divided into constant amplitude and variable amplitude tests. The ratio between the nominal bending and shear stress is 1. For the variable amplitude tests, a Gaussian‐standard is used. A lifetime prediction software for multiaxial state of cyclic stress was developed. The software has a modular structure and allows calculations with different hypotheses and methods. The calculations are based on the local elastic stresses. This is an acceptable method for high‐cycle fatigue. In this work, two general types of calculation, the Integral Approach and Critical Plane Approach and a local stress‐based modification of the von Mises Criterion, the hypothesis of effective equivalent stress (EESH) are shown. The damage accumulation is performed with the elementary Miner’s rule (S–N curve without fatigue limit). The statistical distributions of the damage sums are also shown.

Using non-equilibrium molecular dynamics (NEMD) simulation, we study thermal properties of the so-called nanoporous graphene (NPG) sheet which contains a series of nanoporous in an ordered way and was synthesized recently (Science 360 (2018), 199).The dependence of thermal conductivity on sample size, edge chirality, and porosity concentration are investigated. Our results indicate that the thermal conductivity of NPG is about two orders smaller compared with of pristine graphene. Therefore this sheet can be used as a thermoelectric material. Also, the porosity concentration helps us to tune the thermal conductivity. Moreover, the results show that the thermal conductivity increases with growing sample length due to ballistic transport. On the other hand, along the armchair direction, the thermal conductivity is larger than zigzag direction. We also examined the thermal properties of the interface of NPG and graphene. The temperature drops significantly through the interface leading to the thermal resistance. The thermal resistance changes with imposed heat flux direction, and this difference cause significantly large thermal rectification factor, and heat current prefers one direction to another. Besides, to investigate those quantities fundamentally, we study the phonon density of states and scattering of them.2

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The use of carbon nanotubes as anticancer drug delivery cargo systems is a promising modality as they are able to perforate cellular membranes and transport the carried therapeutic molecules into the cellular components. Our work describes the encapsulation process of a common anticancer drug, Isatin (1H-indole-2,3-dione) as a guest molecule, in a capped single-walled carbon nanotube (SWCNT) host with chirality of (10,10). The encapsulation process was modelled, considering an aqueous solution, by a molecular dynamics (MD) simulation under a canonical NVT ensemble. The interactions between the atoms of Isatin were obtained from the DREIDING force filed. The storage capacity of the capped SWCNT host was evaluated to quantify its capacity to host multiple Isatin molecules. Our results show that the Isatin can be readily trapped inside the volume cavity of the capped SWCNT and it remained stable, as featured by a reduction in the van der Waals forces between Isatin guest and the SWCNT host (at approximately − 30 kcal mol−1) at the end of the MD simulation (15 ns). Moreover, the free energy of encapsulation was found to be − 34 kcal mol−1 suggesting that the Isatin insertion procedure into the SWCNT occurred spontaneously. As calculated, a capped SWCNT (10,10) with a length of 30 Å, was able to host eleven (11) molecules of Isatin, that all remained steadily encapsulated inside the SWCNT volume cavity, showing a potential for the use of carbon nanotubes as drug delivery cargo systems.

In this study, we investigate the thermal rectification and thermal resistance in the hybrid pillared-graphene and graphene (PGG) system. This is done through the classical molecular dynamics simulation (MD) and also with a continuum model. At first, the thermal conductivity of both pillared-graphene and graphene is calculated employing MD simulation and Fourier's low. Our results show that the thermal conductivity of the pillared-graphene is much smaller than the graphene by an order of magnitude. Next, by applying positive and negative temperature gradients along the longitudinal direction of PGG, the thermal rectification is examined. The MD results indicate that for the lengths in the range of 36 to 86 nm, the thermal rectification remains almost constant (~3-5%). We have also studied the phonon density of states (DOS) on both sides of the interface of PGG. The DOS curves show that there is phonon scattering at low frequencies (acoustic mode) that depends on the imposed temperature gradient direction in the system. Therefore, we can 2 introduce the PGG as a promising thermal rectifier at room temperature. Furthermore, in the following of this work, we also explore the temperature distribution over the PGG by using the continuum model. The results that obtained from the continuum model predict the MD results such as the temperature distribution in the upper half-layer and lower full-layer graphene, the temperature gap and also the thermal resistance at the interface.