PAMM Pub Date : 2023-12-21 DOI: 10.1002/pamm.202300237

Vikas Diddige, A. Seupel, Stephan Roth, Bjoern Kiefer

{"title":"A phase‐field model for hydrogen‐promoted fracture based on a mixed rate‐type variational setting","authors":"Vikas Diddige, A. Seupel, Stephan Roth, Bjoern Kiefer","doi":"10.1002/pamm.202300237","DOIUrl":"https://doi.org/10.1002/pamm.202300237","url":null,"abstract":"Certain metals experience a substantial deterioration in mechanical properties when exposed to a hydrogen environment, an effect termed hydrogen embrittlement. To understand, predict, and counteract this hydrogen‐assisted material degradation, sufficiently accurate material models are needed. According to the current hypothesis, hydrogen diffusion is driven by gradients of concentration and hydrostatic stress. To capture this, a phase‐field model is formulated as a multi‐field problem coupling deformation, crack propagation, and diffusion to analyze hydrogen‐promoted fracture. Here, the displacements, a fracture‐related phase‐field, the hydrogen lattice occupancy, and the chemical potential are considered as primary field variables. Approaches proposed in the literature often use an extrapolation of the hydrostatic stress calculated at the material point level onto the nodes and later use the B‐matrix to compute the gradient of hydrostatic stress. In order to circumvent this potentially inaccurate extrapolation, the model is recast into a mixed rate‐type variational setting, where the chemical potential—whose gradient governs the hydrogen flux—is obtained from the numerical solution of a saddle point problem. A representative boundary value problem is presented to demonstrate the applicability of the developed numerical framework.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Gender differences in cycling motions: On objective functions for urban cycling 自行车运动中的性别差异：关于城市自行车的目标函数

PAMM Pub Date : 2023-12-15 DOI: 10.1002/pamm.202300202

Ramona Hoffmann, Clemens Schwöbel, Daniel Kelkel, Sigrid Leyendecker

{"title":"Gender differences in cycling motions: On objective functions for urban cycling","authors":"Ramona Hoffmann, Clemens Schwöbel, Daniel Kelkel, Sigrid Leyendecker","doi":"10.1002/pamm.202300202","DOIUrl":"https://doi.org/10.1002/pamm.202300202","url":null,"abstract":"Societal challenges such as climate change and the energy crisis are putting bicycles at the centre of many people's mobility considerations ‐ but not all. In addition to the need for improved infrastructure, stability and comfort when cycling also play a major role. Simulations offer the possibility to investigate the influence of biometric differences on comfort and stability more cost‐effectively than the measurement methods currently used for bike fitting. Bicycle dynamics and multibody simulation of cycling motions have been the subject of research for a long time. Often data‐driven models are used that follow pre‐established measurement data. Moreover, optimal control simulations for competitive sports are available, where for example, the travel distance during a given time is maximised. However, such models are usually based on the biometric data of an average 18–25 year old male, while the influence of gender differences on cycling motions are rarely explored. Yielding towards closing this gender data gap, we use a discrete mechanics and optimal control framework (DMOCC), which benefits from its structure preserving formulation and has been successfully used for biomechanical applications before. The implemented multibody model of a leg performing a cycling motion can be adapted to individual 3D scans via the geometry parameters and the bounds on the joint angles and torques, providing the possibility to investigate the influence of biometric diversity on the resulting motions. In this first approach, we discuss several possibilities to formulate appropriate objective functions for cycling. The final aim of this study is to supplement a given bike frame by software chosen adaptations so that it optimally fits to individual biometric conditions, thus increasing comfort, the sense of safety and performance, which ultimately enables greater participation in the mobility transition for women, children, and seniors.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"261 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139177850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Artificial neural network surrogate modeling for uncertainty quantification and structural optimization of reinforced concrete structures 用于钢筋混凝土结构不确定性量化和结构优化的人工神经网络代用模型

PAMM Pub Date : 2023-12-01 DOI: 10.1002/pamm.202300286

S. Freitag, P. Edler, Stefanie Schoen, Gunther Meschke

{"title":"Artificial neural network surrogate modeling for uncertainty quantification and structural optimization of reinforced concrete structures","authors":"S. Freitag, P. Edler, Stefanie Schoen, Gunther Meschke","doi":"10.1002/pamm.202300286","DOIUrl":"https://doi.org/10.1002/pamm.202300286","url":null,"abstract":"Optimization approaches are important to design sustainable structures. In structural mechanics, different design objectives can be defined, for example, to minimize the required construction material or to maximize the structural durability. In this paper, the durability of a reinforced concrete (RC) structure is assessed by advanced finite element (FE) models to simulate the cracking behavior and the chloride transport process. The corrosion initiation time is used as durability measure to be maximized within an optimization approach, where the concrete cover is defined as design variable. The variability of structural loads and material parameters and unavoidable construction imprecision leads to a probabilistic reliability and durability assessment, where aleatory as well as epistemic uncertainties are quantified by random variables, intervals and probability‐boxes. The FE simulation models cannot directly be applied to structural analyses and optimizations with polymorphic uncertain parameters and design variables because of the high computational demand of the multi‐loop algorithm (Monte Carlo simulation, interval analysis, global optimization). In this paper, a new surrogate modeling strategy is presented, where artificial neural networks are trained sequentially to speed‐up the coupled mechanical and transport simulation FE models. The new approach is applied to the uncertainty quantification and the structural durability optimization of a RC structure.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"24 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139192444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Monolithic FE2 approach for the thermomechanical modeling of beam structures 用于梁结构热力学建模的单片 FE2 方法

PAMM Pub Date : 2023-12-01 DOI: 10.1002/pamm.202300259

S. Klarmann, P. Gebhart, T. Wallmersperger, Sven Klinkel

{"title":"Monolithic FE2 approach for the thermomechanical modeling of beam structures","authors":"S. Klarmann, P. Gebhart, T. Wallmersperger, Sven Klinkel","doi":"10.1002/pamm.202300259","DOIUrl":"https://doi.org/10.1002/pamm.202300259","url":null,"abstract":"In the present contribution, the FE2 scheme for beam elements is extended to thermomechanically coupled problems. Beam elements have the advantage of drastically reducing the number of degrees of freedom compared to solid elements. However, the major challenge in modeling structures with beam elements lies in developing sophisticated non‐linear beam material models. This drawback resides in the fact that these elements require effective cross‐sectional properties involving material and geometric properties. The FE2 method, combined with a homogenization scheme based on the Hill‐Mandel condition, solves this problem. Within this scheme, homogenization of a representative volume element (RVE) on the mesoscopic scale provides effective cross‐sectional properties for the macroscopic scale. This homogenization procedure allows the consideration of non‐linear material formulations and cross‐sectional deformation within the analysis of a beam structure. The applicability of such a FE2 scheme for purely mechanical problems was already shown. In the present contribution, an extension to thermomechanically coupled problems is provided. In the proposed setting, the macroscopic scale is represented by beam elements with displacement, rotation, and temperature degrees of freedom. Solid elements with displacements and temperature degrees of freedom describe the behavior of the RVE. Hence, the proposed extension solves both scales in a monolithic approach. The assumption of a steady state problem at both scales allows a focus on a consistent scale transition and a discussion about the choice of suitable boundary conditions under the assumption of beam kinematics.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"14 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139190937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Performance estimation of small‐scale horizontal axis wind turbine blade 小型水平轴风力涡轮机叶片的性能评估

PAMM Pub Date : 2023-12-01 DOI: 10.1002/pamm.202300284

R. Laouar, Riyadh Bekkai, R. Mdouki

引用次数: 0

Control‐oriented models of the shallow water equations using energy‐conserving discretization schemes 使用能量守恒离散方案的浅水方程控制导向模型

PAMM Pub Date : 2023-12-01 DOI: 10.1002/pamm.202300267

Luca Mayer, Jens Wurm, F. Woittennek

引用次数: 0

Improving flushing processes through targeted control of the temperature boundary conditions 通过有针对性地控制温度边界条件改进冲洗工艺

PAMM Pub Date : 2023-11-27 DOI: 10.1002/pamm.202300253

V. Liebmann, Matti Heide, Hannes Köhler, F. Rüdiger, Jochen Fröhlich

{"title":"Improving flushing processes through targeted control of the temperature boundary conditions","authors":"V. Liebmann, Matti Heide, Hannes Köhler, F. Rüdiger, Jochen Fröhlich","doi":"10.1002/pamm.202300253","DOIUrl":"https://doi.org/10.1002/pamm.202300253","url":null,"abstract":"In this contribution the authors investigate how flushing of chocolate using a follow‐up chocolate in a straight horizontal pipe is affected by temperature. The authors investigate a non‐uniform distribution of temperature across the considered domain. This is done using two cases, where the first exhibits a wall temperature deviating from the normal process temperature and the second exhibits a differently tempered follow‐up chocolate. The investigations are performed using unsteady three‐dimensional numerical simulations with an OpenFOAM multiphase solver, which is extended to include an additional equation for energy conservation. The physical properties of the chocolate are analyzed with respect to their dependence on temperature and implemented in a new model in OpenFOAM. The results of both cases are assessed according to industrially relevant questions. Among others, they include the amount of follow‐up chocolate needed to achieve a set goal of cleanliness. The time needed to achieve this is also considered. A dimensionless time is used to compare the different cases. Recommendations are provided on how different temperature of pipe wall and follow‐up chocolate may lead to improved flushing processes and which savings may be achieved with this strategy.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139228721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Electro‐chemo‐mechanical modeling of structural battery electrode materials 电池电极结构材料的电化学机械建模

PAMM Pub Date : 2023-11-27 DOI: 10.1002/pamm.202300137

David Rollin, F. Larsson, K. Runesson, R. Jänicke

引用次数: 0

Investigating the impact of deformation on foam permeability through CT scans and the Lattice‐Boltzmann method 通过 CT 扫描和格子-玻尔兹曼法研究变形对泡沫渗透性的影响

PAMM Pub Date : 2023-11-27 DOI: 10.1002/pamm.202300154

Nguyen Thien Phu, U. Navrath, Y. Heider, J. Carmai, Bernd Markert

{"title":"Investigating the impact of deformation on foam permeability through CT scans and the Lattice‐Boltzmann method","authors":"Nguyen Thien Phu, U. Navrath, Y. Heider, J. Carmai, Bernd Markert","doi":"10.1002/pamm.202300154","DOIUrl":"https://doi.org/10.1002/pamm.202300154","url":null,"abstract":"Foam has a wide range of applications, where the study of its properties and mechanical response has gained a lot of attention in recent years. To deepen the understanding of foam's behavior, the underlying research proposes a new study to determine the deformation‐dependent permeability of foam using a combination of CT scans and the Lattice‐Boltzmann method (LBM). Specifically, the three‐dimensional mesoscopic structure of the foam is reconstructed using nano‐CT images at different compression levels including uncompressed, 15, 25, 35, and 50 percentages of compression. After processing the data from the CT scans, the LBM is applied to simulate single‐phase fluid flow in the deformed porous domain. The permeability at each corresponding deformation stage is characterized and determined by the LBM using the open‐access Palabos software. In this work, the deformation‐dependent intrinsic permeability tensor is considered by applying a meso‐macro hierarchic upscaling scheme. According to the CT scan outcomes, the compression level is inversely proportional to the porosity. The physical phenomenon is discussed in detail and the effect of image resolution on the permeability computation accuracy is investigated.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"277 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139231634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Latent heat effects in inductive heating of shape memory alloy fibers 形状记忆合金纤维感应加热中的潜热效应

PAMM Pub Date : 2023-11-23 DOI: 10.1002/pamm.202300300

S. Descher, Philipp Krooß, Felix Ewald, Sebastian Wolf, Detlef Kuhl

{"title":"Latent heat effects in inductive heating of shape memory alloy fibers","authors":"S. Descher, Philipp Krooß, Felix Ewald, Sebastian Wolf, Detlef Kuhl","doi":"10.1002/pamm.202300300","DOIUrl":"https://doi.org/10.1002/pamm.202300300","url":null,"abstract":"Motivation of the present work is an inductive heating process, used in manufacturing a new kind of improved ultra‐high performance concrete. In this novel material, fibers made out of shape memory alloys are used to increase the maximum possible fiber volume fraction, or to create an internal state of compressive stress. In contrast to other works, the underlying microstructure transformation from martensite to austenite is highlighted based on thermal analysis. Dynamic scanning calorimetry measurements are adapted as basis for development of a phenomenological phase transformation model. It relates local temperature and temperature rate to the rate of change of the phase indicator, modeling the transformation of martensite to austenite. Latent heat is considered by an enthalpy method, the inductive heating process is considered by a phenomenological model. Study results for a purely thermodynamic process of heating a single fiber embedded in concrete are presented. They show that latent heat effects delay phase transformation and the process of fiber activation is very sensitive to the induced heat. Furthermore, it is discovered that latent heat causes a strongly inhomogeneous state of transformation in radial direction of the fiber, which is of great importance for thermomechanical processes and the interpretation of experimental results.","PeriodicalId":510616,"journal":{"name":"PAMM","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139244674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

PAMM最新文献