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Preface The Nordic Association for Computational Mechanics (NoACM) was founded in October 1988 in Gothenburg, Sweden among the first organizations established in this field. Ever since the objective of NoACM has been to stimulate and promote research and practice in computational mechanics, to foster the interchange of ideas among the various fields contributing to computational mechanics, and to provide forums and meetings for dissemination of knowledge about computational mechanics. In particular, presentations by graduate students have always been welcomed. Thus, making a friendly and creative atmosphere for the participants is considered important. This year’s seminar is already the 32nd in the series. It is arranged for the first time in the municipality of Oulu located in the region of North Ostrobothnia in Finland. This is probably one of the northernmost locations in the world where a seminar on computational mechanics has ever been arranged. The seminar has attracted around 50 contributions distributed in two parallel sessions over two days. The organizers would like to thank all authors for submitting their contributions, as well as their supporting organizations, to make NSCM32 in Oulu possible! Linnanmaa, Oulu, 18 October, 2019 Antti H. Niemi Hannu Koivurova Table of contents Preface Committees Map of downtown Oulu Program Plenary lectures: Marrying computational mechanics and materials science. L.-E. Lindgren Higher Order Haar Wavelet Method. Application for Analysis of FGM and Nanostructures. J. Majak, M. Kirs, M. Ratas Hybrid Modeling as an enabler for Big data cybernetics. A. Rasheed Material Point Method: the past and the future. W. Solowski A single-cell computation for dynamic turbulent cascade development — the ‘Navier-Stokes Machine’. C. M. Velte, P. Buchhave Contributed papers: Shape and topology optimization using CutFEM. N. Aage, R. Giele, S. Dilgen, C. Dilgen and C. S. Andreasen A posteriori Error Estimation for Isogeometric Analysis of the Advection-Diffusion equation. A. Abdulhaque, T. Kvamsdal, M. Kumar and A. M. Kvarving Microstructural modelling of defect containing martensitic steels. T. Andersson, A. Laukkanen, M. Lindroos, S. Majaniemi, T. Suhonen, T. Frondelius, J. Vaara, A. Mäntylä On the regularisation property of the Kachanov-Rabotnov continuum damage model — a finite element study. H. Askes, J. Hartikainen, K. Kolari, R. Kouhia, T. Saksala and J. Vilppo Variationally consistent homogenization of phase field fracture model. R. Bharali, R. Jänicke and F. Larsson Calibration of Abaqus CDP model parameters. K. Calonius, A. Fedoroff, K. Kolari, R. Kouhia and J. Vilppo Deep learning for future state estimation of the unsteady flows. H. Eivazi, M. Masdari, and R. Soleymani On error-controlled numerical model reduction for computational homogenization of porous media. F. Ekre, F. Larsson, K. Runesson and R. Jänicke Comparison of hygrothermal simulation techniques in northern conditions. F. Fedorik, H. Lahtinen, H. Koivurova and A. H. Niemi MFrontInterface.jl: MFront material models in JuliaFEM. T. Frondelius, T. Helfer, I. Yashchuk, J. Vaara, and A. Laukkanen Modeling of non-coulomb friction under fretting conditions part 2. J. Hintikka, A. Mäntylä and T. Frondelius A Modal System Reduction Procedure for a Flexible Structure with a Flexible Vibration Absorber. J. Høgsberg JuliaFEM geometry optimization. J. Huopana, T. Rantakivi, M. Väntänen, A-J. Vuotikka, A. Tanskanen, J. Vaara, S. Sikkilä and T. Frondelius Inelastic buckling of plates subjected to multi axial in-plane loads. A. Jahanpour and R. Kouhia A new material contrast model for use in topology optimization of steady-state dynamic problems. J. S. Jensen How about version control? J. Jeronen On the integration of an evolution equation based high-cycle fatigue model. J. Jeronen, R. Kouhia, J. Lahtinen and H. Orelma Cost-optimized rise of tied-arch bridges. E. Järvenpää and A. H. Niemi Micropolar plate model for lattice core sandwich panels. A. Karttunen, P. Nampally, J. N. Reddy and J. Romanoff Finite element modeling of Al6082 Plasma Electrolytic Oxidation coatings. S. Khakalo, A. Laukkanen, T. Suhonen, K. Holmberg, E. Bousser, A. Yerokhin, P. J. Withers, and A. Matthews Goal Oriented Adaptive Isogeometric Methods applied to Structural Mechanics. T. Kvamsdal, M. Kuma, A. M. Kvarving and K. M. Okstad Least Squares Stabilized Nitsche in CutIGA. M. G. Larson and K. Larsson Thurster Driveline Digital Twin — Bearing and Shaft Fatigue Life Prediction. T. Leppänen Modeling friction and wear in dynamically loaded clamped metal contacts. A. Mäntylä, J. Hintikka and T. Frondelius A numerical framework for rate-independent for Fleck and Willis crystal plasticity. K. L. Nielsen Reliability of Finnish steel trusses under snow load in light of the design standard EN 1990. A. H. Niemi Parametric modelling of cellular beam and plate structures by orthotropic strain gradient thermo-elasticity. J. Niiranen, S. Khakalo and V. Balobanov Achilles tendon modeling based on the absolute nodal coordinate formulation. L. Obrezkov, A. B. Harish and M. Matikainen On optimal design of lug joints. N. L. Pedersen FEM-DEM in Modeling Ice-structure Interaction Process. J. Ranta, A. Polojärvi and J. Tuhkuri Comparison 32CrMo12 QT steel fatigue testing with ultrasonic and servo-hydraulic testing machines. T. Rantakivi, M. Väntänen, J. Kuoppala, J. Vaara, J. Larkiola and T. Frondelius Waveguides that support trapped surface waves. K. Ruotsalainen Numerical modelling of concrete fracture: a mesoscopic approach based on embedded discontinuity FEM. T. Saksala On periodic boundary conditions in Variationally Consistent Homogenisation of beams and plates. A. Sciegaj, P. Grassl, F. Larsson, K. Lundgren and K. Runesson Numerical analysis of coupled nerve signal propagation. K. Tamm, T. Peets and J. Engelbrecht Nonlinear bending of microarchitectural thin beams within strain gradient elasticity. L. V. Tran and J. Niiranen Continuum damage modelling of quasi-brittle materials by using the material point method. Q-A. Tran, T. H. A. Nguyen, J. Niiranen and W. Solowski Finite Element Simulation of the Performance of a Structural Electrolyte. V. Tu, L. E. Asp, N. Shirshova, F. Larsson, K. Runesson, and R. Jänicke Mathematical modelling of sustainable bioresidual concrete. T. Tuovinen, T. Leppänen, J. Parkkonen, J. Virkajärvi and L. Turunen Comparison of selected sequential design of experiment strategies for fatigue testing. J. Vaara, M. Väntänen, J. Kemppainen and T. Frondelius Crankshaft impact modelling. A-J. Vuotikka, M. Jokinen, P. Halla-aho, J. Aho, A. Mäntylä and T. Frondelius Fatigue Testing — Informativity of the Experimental Data. M. Väntänen, J. Vaara, J. Kemppainen and T. Frondelius Multiscale design optimization of structures with solid coating and periodic infill lattice. E. Wadbro and B. Niu List of Authors

Axially moving material problems are concerned with the dynamic response, vibration and stability of slender members which are in a state of translation. In Finland these are particularly important in the functioning of paper machines, in which out of plane vibration in the paper web, known as flutter, which from the point of view of mechanics is a phenomenon typical of an axially moving material, limits operation speeds and therefore the productivity of the machines. This subject links together a number of physical phenomena associated with aerodynamics, web movement, material behaviour and the geometry of the system. The aim of this research is to present a theoretical and numerical formulation of the nonlinear dynamic analysis of an axially moving web. The theoretical model is based on a mixed description of the continuum problem in the context of the dynamics of initially stressed solids. Membrane elasticity is included via a finite strain model, and the membrane transport speed through a kinematical study. Hamilton’s principle provides nonlinear equations which describe the three-dimensional motion of the membrane. The incremental equations of Hamilton’s principle are discretized by the finite element method. The formulation includes geometrically nonlinear effects: large displacements, variations in membrane tension and variations in transport velocity due to deformation. This novel numerical model was implemented by adding an axially moving membrane element to a FEM program which contains acoustic fluid elements and contact algorithms. This allowed analysis of problems including interaction with the surrounding air field and contact between supporting structures. The model was tested by comparing previous experiments and present nonlinear description of the dynamic behaviour of an axially moving web. The effects of contact between finite rolls and the membrane and interaction between the surrounding air and the membrane were included in the model. The results show that nonlinearities and coupling phenomena have a considerable effect on the dynamic behaviour of the system. The nonlinearities cause a noticeable stiffening of the membrane, and the vibration frequency of nonlinear system increases as the amplitude grows. At high values of transport velocity the first mode frequency passes over the second linear harmonic, and even the third. The results also show that the cylindrical supports have a distinct influence on the behaviour of an axially moving sheet. The boundary of the contact region clearly moves and weakens the nonlinear hardening phenomena that otherwise increase the fundamental frequency. This influence strengthens as the radius of the cylinders increases.

A computationally efficient strategy to prescribe periodic boundary conditions on three- dimensional Representative Volume Elements (RVEs) is outlined. In particular, the cases of having an Euler-Bernoulli beam and a Kirchhff-Love plate problem at the macroscale are considered within a computational homogenisation framework. Special solid elements for the boundary region of the periodic mesh have been developed, in which some of the degrees of freedom depend on those of their periodic counterparts, the macroscopic data and the size of the RVE.

A lug or pinned connection is a simple assembly type that allows for quick assembly and disassembly. The connection have many practical applications both in mechanical and civil engi-neering cases. In the present work the loading on the assembly is assumed to be cyclic so that the design criteria for strength is fatigue, i.e. the maximum stress in the assembly. The usual design of lug joints is controlled by standards, e.g. ISO2338.The stress state is 3 dimensional but still the normal design is constant through the thickness so focus is on the cross sectional design. The typical sectional design is circular and stress concentration factor charts can be found in the literature. The typical assumption used is that it is sufficient to use a 2D model, where a further assumption of either plane stress or plane strain is needed. In practical designs where the thickness is of the same order as the pin diameter we find that there is a significant variation in the stress in the axial direction. The same type of variation is also found in e.g. interference fits, see e.g. [1]. For simplification we will however here neglect the 3D effect on the stress concentration.In the present work the aim is to minimize the stress concentration resulting in an increased strength of the connection. The finite element method (FEM) is used as the analysis tool, and for the successful application a number of aspects must be taken into account, and will be discussed in relation to the design. The different aspects includes:-The definition of the stress concentration factor.-Mesh refinement (in non-linear contact analysis).-Head distance.-Poisson's ratio.-Plane stress or plane strain.-Friction.-Clearance.The design optimization is performed using shape optimization. For the present optimizationwe have the special case that the shape to be designed is the contact zone. The selected shape parameterization used is the super elliptical one. Further information can be found in [2].

A vast amount of research continues to go into developing robust numerics to handle rate-independent crystal plasticity - either by making use of additional constitutive models or complex numerics. The present work attempts to circumvent such special measures by taking a new approach to develop a numerical solution procedure for a rate-independent crystal plasticity, relying on the Fleck and Willis gradient plasticity theory. The adopted constitutive model reduces to that of conventional plasticity in the limit of zero length parameter and, thus, constitutes a tool that covers both branches of plasticity.