Sandro Wartzack

• Prof. Dr.-Ing.
• Chair at Friedrich-Alexander-University Erlangen-Nürnberg

The ideating phase of product design is critical, as decisions made here influence the rest of the product’s lifecycle. Usually, early preliminary designs in engineering are created with pen and paper, which are incompatible with the subsequent digital design process. In an effort to find a modeling tool for early designs that provides the creative...

Digital Twins have numerous potentials like performance analysis, condition monitoring or process optimization. As the development of Digital Twins is a highly interdisciplinary task, it poses challenges and is therefore rarely utilized. This contribution considers the interdisciplinary development of Digital Twins as an interplay between sensors,...

The shifting demographics worldwide signal a looming challenge: an increasingly aging population. Along with this demographic shift comes an increase in age-related health issues, with neurological conditions like strokes being especially prominent. Patients who suffering on such diseases often have a so-called plantar and dorsal weakness, i.e. a r...

This paper presents a conceptual framework aimed at integrating Digital Twins and cyber-physical production systems into the energy management of manufacturing facilities. To address the challenges of rising energy costs and environmental impacts, this framework combines digital modeling and customized energy management for direct manufacturing ope...

Early robust design (RD) can lead to significant cost savings in the later stages of product development. In order to design systems that are insensitive to various sources of deviation in the early stages, specific design knowledge (SDK) plays a crucial role. Different design situations result in higher or lower levels of derivable SDK, which lead...

During split-belt treadmill walking, neurotypical humans exhibit slow adaptations, characterized by a gradual decrease in step length asymmetry, whereas individuals with cerebellar damage do not show these motor adaptations. We used a neuromusculoskeletal model to better understand individual aspects of the underlying neural control. Specifically,...

Carbon fiber reinforced plastic (CFRP) parts find a rising number of applications as structural components. Therefore, new manufacturing technologies are developed, enabling high volume production of such parts. With those higher volumes, variation management during product design becomes more critical. While manufacturing variations in CFRP materi...

This work presents a novel infill method for additive manufacturing, specifically designed to optimize material use and enhance stiffness in fused filament fabrication (FFF) parts through a geometry-aware, corrugated design inspired by sandwich structures. Unlike standard infill patterns, which typically employ uniform, space-filling grids that oft...

Efficient characterization of fatigue behavior plays a crucial role in engineering design as it reduces the financial costs associated with expensive experimental tests. Existing methods for characterizing the fatigue behavior of fibre-reinforced plastics have proven inefficient due to the oversight of important design parameters, such as fibre ori...

There is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomed-ical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-...

Driven by the opportunities for condition monitoring and other new business models, Digital Twins have become a popular topic within research and industrial application over the last years. This contribution presents an approach for the reuse and utilization of system models as core models for the Digital Twin. Furthermore, it aims to build up the...

Fibre-reinforced plastics are increasingly being used in important structural components. Here they are often subjected to cyclic loading, which leads to a deterioration in material properties. However current design methods hardly take this fatigue behavior into account. Instead, they rely on conservative safety factors, resulting in over-dimensio...

In the context of tolerance management, the consideration of manufacturing and assembly processes is becoming increasingly important. The main drivers for this are, above all, short development times and high-quality requirements, leading to tight tolerances. To overcome the resulting challenges, many publications address the process-oriented toler...

Additive manufacturing (AM) is characterized by great design freedom and batch size-independent manufacturing costs, and also offers the possibility of manufacturing moving mechanisms in a single manufacturing step. A subsequent assembly step thus becomes obsolete, consequently leading to a considerable cost reduction. However, AM processes have th...

A product generally proceeds through development, production and assembly before it goes into operation. In particular, iterations often occur between development and production, although information are usually only passed on systematically in one direction. Errors during development and especially during tolerancing, scheduled at the end of the d...

With rising demands and regulations for efficient and sustainable products, the use of high performance composite materials rises. There are a large number of manufacturing processes for composite materials, which inevitably lead to variations. Consideration of variations during product development is therefore particularly important for products o...

Products are nowadays characterized by rising complexity, so that companies need to adapt their development processes to resulting challenges. Transferring this need for adaption to the tolerancing domain, new approaches are expected to enable companies to tackle increasing quality demands and costs pressures. Resulting from that, a variety of tole...

Tolerance allocation is an essential tolerancing activity to assure the manufacturability of the individual parts, their assembly to the final product, and its functionality in use. Design engineers are responsible for assigning the values for all tolerances specified to limit the critical geometrical part variations. The challenge is to allocate t...

Rolling bearings range among the most important machine elements and are frequently deployed wherever rotating parts must be supported. Consequently, they are typically subject to a high number of load cycles, which may cause fatigue resulting in premature failure. The layout of bearings and their seats is therefore a crucial activity during the de...

Digital Twins are a promising technology to increase the value of products and create new business models. As models are an essential component of these Digital Twin concepts, the reuse of models is necessary. With this contribution, a methodical approach for the integration of a manufacturing structure into a system model is introduced for early v...

Bearing life calculation is a well-researched and standardized topic for rotating operation conditions. However, there is still no validated and standardized calculation for oscillating operation, only different calculation approaches. Due to the increasing number of oscillating rolling bearings, for example, in wind turbines, industrial robots, or...

Digital transformation is omnipresent in our daily lives and its impact is noticeable through new technologies, like smart devices, AI-Chatbots or the changing work environment. This digitalization also takes place in product development, with the integration of many technologies, such as Industry 4.0, digital twins or data-driven methods, to impro...

Rolling bearings are of great importance in all areas of mechanical engineering due to their precise and low-friction guidance of rotating components at low cost. The design of rolling bearing arrangements is usually based on approximately ideal geometries of bearings and adjacent parts on which the bearing seats are located. However, real componen...

Computational research methods, such as finite element analysis (FEA) and musculoskeletal multi-body simulation (MBS), are important in musculoskeletal biomechanics because they enable a better understanding of the mechanics of the musculoskeletal system, as well as the development and evaluation of orthopaedic implants. These methods are used to a...

Digital Twins are perceived differently between and within industry and academia regarding applications and potentials. For this reason, a round table was formed based on the Digital Twin Workshop of the Design Conference 2022. One of the results of this round table is this contribution, which deals with a survey within the industry. The survey cap...

Designing an equally usable and emotionally appealing product remains a challenge for product developers, not least due to conflicting goals. Product developers need to constantly map the affective user requirements to the product, whereby the requirements for the emotional and usable product design often cannot be equally addressed. The systematic...

The amount of data within the product development process requires a structured approach to coordinate them. Knowledge management solutions, such as ontologies, are a suitable way of linking data and representing semantic relationships. However, making all relevant data usable to ensure their target-oriented application is still a challenge. Thus,...

Transferring natural language requirements to use case diagrams helps to avoid inherent ambiguities. However, this is usually a manual, time-consuming task that can be accelerated by utilizing Artificial Intelligence in terms of Natural Language Processing. Thus, this contribution proposes a conceptual framework for automatically grouping interrela...

The human's upright standing is a complex control process that is not yet fully understood. Postural control models can provide insights into the body's internal control processes of balance behavior. Using physiologically plausible models can also help explaining pathophysiological motion behavior. In this paper, we introduce a neuromusculoskeleta...

In musculoskeletal simulation, individualized joint axes enhance the accuracy and reliability of kinematic and kinetic simulation results. We investigated the correctness and performance of an analytical method for identifying the instantaneous axis of rotation between two bodies based on motion data in OpenSim. The instantaneous center of rotation...

According to the analysis of the Global Burden of Disease (GBD) approximately 1.71 billion people worldwide suffer from musculoskeletal disorders. For the treatment of gait pathologies ankle foot orthoses (AFO) are used in the field of rehabilitation and physiotherapy. However, conventional AFOs are pre-terminated to fit a wide range of user groups...

Raising the user’s self-confidence is a promising strategy to reduce product-related user stigma. In the context of product usage, the commonly used term self-confidence refers to the psychological construct of self-efficacy. To strengthen a user’s self-efficacy through product design, providing both good usability and emotionality in a product see...

The load-adaptive behavior of the muscles in the human musculoskeletal system offers great potential for minimizing resource and energy requirements in many technical systems, especially in drive technology and robotics. However, the lack of knowledge about suitable technical linear actuators that can reproduce the load-adaptive behavior of biologi...

The integration of Digital Twins (DTs) is becoming increasingly important in various industries. This entails the need for a comprehensive and practical IT infrastructure framework. This paper presents a modifiable medium-level architecture that serves as a link between established reference architectures such as RAMI 4.0 and the pragmatic implemen...

Working at and above head height with a power tool represents a common activity in craft and assembly applications. To assist and protect the user from overload and injuries in these situations, the development and use of application-specific support systems, such as exoskeletons and power tools, have greatly increased in recent years. Thus, the in...

The human's upright standing is a complex control process that is not yet fully understood. Postural control models can provide insights into the body's internal control processes of balance behaviour. Using physiologically plausible models can also help explaining pathophysiological motion behaviour. In this paper, we introduce a neuromusculoskele...

The use of system models within model-based systems engineering (MBSE) is essential for improved communication or system documentation. Previous publications have investigated further reuse of these system models, for example, transforming them directly into discipline-specific models for reuse. The authors refer to this as the term “Utilization” o...

This is the supplementary material for the systematic literature review in: https://www.cambridge.org/core/journals/design-science/article/utilization-of-system-models-in-modelbased-systems-engineering-definition-classes-and-research-directions-based-on-a-systematic-literature-review/04066CE1D254458E17969AC5F2D80347#article

Fatigue life testing is a complex and costly matter, especially in the case of fibre-reinforced thermoplastics, where other parameters in addition to force alone must be taken into account. The number of tests required therefore increases significantly, especially if the influence of different fibre orientations is to be taken into account. It is t...

Simulation models are a valuable tool for exoskeleton development, especially for system optimization and evaluation. It allows an assessment of the performance and effectiveness of exoskeletons even at an early stage of their development without physical realization. Due to the closed physical interaction between the exoskeleton and the user, accu...

Design processes are always in motion, since more and more data-driven methods are used for various design and validation tasks. However, small and medium enterprises especially struggle with enhancing their processes with data-driven methods due to a lack of practical and easy-to-use analysis and redesign methods which can handle design process ch...

The rising system complexity of modern products requires new approaches within model-based systems engineering to manage the upcoming challenges. System development is characterized by a wide variety of decisions to be made. These situations have to be modeled within a holistic system model to ensure traceability. Motivated by lack of a comprehensi...

The use of fibre-reinforced plastics (FRP) in structural components offers significant lightweight potential due to their high specific stiffness and strength. However, the complex fatigue behavior of FRP often leads to insufficient consideration of long-term strength during product development, which is typically compensated for by high safety fac...

In der nutzerzentrierten Produktentwicklung wird der Mensch als Summe seiner individuellen physiologischen und psychologischen Ausprägungen verstanden, welche in persönlichen Bedürfnissen an das Produkt resultieren. Diese können auch als affektive Ansprüche definiert werden und sind folglich Anforderungen, die sich aus den individuellen, subjektive...

Sampling-based tolerance analysis is a powerful tool for evaluating the quality of functional products, but requires realistic manufacturingdistributions. However, the determination of resulting manufacturing distributions is usually associated with a high financial and time expenditure,especially for novel technologies such as Additive Manufacturi...

Hydrogen-powered fuel cells will play a vital role in the next generation of energy systems. In this regard, Proton Exchange Membrane Fuel Cells (PEMFC) represent a promising technical solution for all applications where direct electrification is not technically feasible or economically viable, such as the propulsion of heavy vehicles. However, rob...

Inhalt Topologieoptimierung (TO) kann Ausgangspunkt für effizienten Materialeinsatz und hochperformante Leichtbaukomponenten sein. Hierfür ist nach der TO eine Rekonstruktion der Geometrie in einem eigenen Prozessschritt nötig. Insbesondere wenn das Optimierungsergebnis nicht als abstraktes Oberflächenmodell, sondern als parametrische Computer-Aide...

Digital Twins offer vast potential, yet many companies, particularly small and medium-sized enterprises, hesitate to implement them. This hesitation stems partly from the challenges posed by the interdisciplinary nature of creating Digital Twins. To address these challenges, this paper explores systematic approaches for the development and creation...

Service loads repeatedly stress components on a regular basis and lead to fatigue damage in the material. In the case of components made of short fibre-reinforced thermoplastics, which are also crash-relevant in addition to only bearing service loads, however, a significant deterioration in mechanical properties can be observed after fatigue damage...

The growing digitalization trend has a great influence and impact on the entire product development domain. The new algorithms and methods transform and improve many established processes and workflows. In addition to converting existing know-how into the new processes, available data can also be used to implement various models to enhance the deve...

The knowledge of the operating conditions in rolling bearings in technical applications offers many advantages, for example, to ensure a safe operation and to save resources and costs with the help of condition monitoring and predictive maintenance procedures. In many cases, it is difficult to implement sensors to measure the operating conditions o...

Using composite materials like endless fiber reinforced plastics offers numerous advantages. Nevertheless, the material properties of composite materials lead to new challenges in the manufacturing and assembly process. Additionally, variations and uncertainties occurring in the different production steps lead to increased production costs. Therefo...

It is undeniable that mechanical properties, such as the stiffness or residual strength of fibre-reinforced thermoplastics, are adversely affected by fatigue damage caused by cyclic loading. In order to quantify and predict this damage influence, a calculation approach was developed in the past for the subgroup of short-fibre-reinforced thermoplast...

In the development of complex mechatronic systems, interdisciplinary cooperation requires an exchange between stakeholders in order to ensure fulfillment of requirements and related functions. The cooperation of the stakeholders from different disciplines must be well coordinated to address systems changes. The system model as an essential aspect o...

Patients who suffer from foot drop have impaired gait pattern functions and a higher risk of stumbling and falling. Therefore, they are usually treated with an assistive device, a so-called ankle–foot orthosis. The support of the orthosis should be in accordance with the motor requirements of the patient and should only be provided when needed, whi...

Since musculoskeletal disorders are one of the most common work-related diseases for assemblers and machine operators, it is crucial to find new ways to alleviate the physical load on workers. Support systems such as exoskeletons or handheld power tools are promising technology to reduce the physical load on the humans. The development of such syst...

Understanding of the human body’s internal processes to maintain balance is fundamental to simulate postural control behaviour. The body uses multiple sensory systems’ information to obtain a reliable estimate about the current body state. This information is used to control the reactive behaviour to maintain balance. To predict a certain motion be...

This paper presents a procedure model for the experimental determination of wear coefficients by means of a two-disk tribometer. The approach presented allows any slide-to-roll ratios (SRR) to be set in order to be able to reproduce rolling-sliding contacts in addition to pure sliding contacts. The wear coefficients were calculated by means of tact...

In order to improve the tribological performance of PVD–MoS2 coatings, which are frequently used as a solid lubricant for operating in challenging environments, e.g., in a vacuum, they can be modified with nitrogen. This work evaluates the tribological behavior and a possible compaction occurring during the initial tribological load in the rolling...

In the development of complex mechatronic systems, interdisciplinary cooperation requires an exchange between stakeholders in order to ensure fulfillment of requirements and related functions. The cooperation of the stakeholders from different disciplines must be well coordinated to address systems changes. The system model as an essential aspect o...

This work aims to evaluate the current state of research on the use of artificial intelligence, deep learning, digitalization, and Data Mining in product development, mainly in the mechanical and mechatronic domain. These methods, collectively referred to as “digital engineering”, have the potential to disrupt the way products are developed and imp...

Due to the high freedom of design, additive manufacturing (AM) is increasingly substituting conventional manufacturing technology in several sectors. However, the knowledge and the awareness for the suitable design of additively manufactured components or assemblies ensuring manufacturability and fully realizing its potential is still lacking. In r...

Many immersive approaches for design activities show a great potential for their specific use cases, but still overall usage of extended reality technology in product developers day-to-day work is little. The user's workflow between classical desktop work environment and its immersive counterpart is interrupted by both a data gap and an interface g...

Motor disorders are diseases affecting the muscle function of the human body. A frequently occurring motor disorder affects the lower leg muscles resulting in a pathological gait called foot drop. Patients have a higher risk of stumbling and falling. The most common treatment is the use of a passive ankle-foot-orthosis (AFO). However, the compensat...

The digitalization trend is finding its way more and more into product development, resulting in new frameworks to enhance product engineering. An integral element is the application of new techniques to existing data, which offers an enormous potential for time and cost savings, because duplicate work in product design and subsequent steps is avoi...

Requirements represent a central element in product development. The large number of requirements inevitably results in an increased susceptibility to errors, an expenditure of time and development costs. The associated problems motivate the application of Artificial Intelligence in the form of Natural Language Processing (NLP). In Requirements Eng...

The tolerancing of products for manufacturing is usually performed at the end of the design process and the responsibility of the designer. Although components are commonly tolerated to ensure functionality, time-based influences, like wear, that occur during operation, are often neglected. This could result in small amounts of scrap after producti...

With increasing life expectancy, the risk of diseases of the central nervous system, such as cancer, strokes, etc., also increases. Strokes often result in injury to the sciatic nerve, which is responsible for controlling the calf muscles (plantar and dorsal flexors). A so-called ankle joint orthosis (AFO) helps to support the pathological gait and...

The early use of Robust Design (RD) supports the development of product concepts with low sensitivity to variation, which offers advantages for reducing the risk of costly iterations. Due to the lack of approaches for early evaluation of product robustness, the embodiment-function-relation and tolerance (EFRT-) model was developed, which combines t...

Topology Optimization (TO) is an established method for the development of high strength and lightweight structural components. However, its results have to be geometrically revised to obtain a computational model that meets product development requirements. Design has to be in accordance with manufacturing constraints. Geometry reconstruction ther...

Biomechanical simulation allows for in silico estimations of biomechanical parameters such as muscle, joint and ligament forces. Experimental kinematic measurements are a prerequisite for musculoskeletal simulations using the inverse kinematics approach. Marker-based optical motion capture systems are frequently used to collect this motion data. As...

The individualization of patient-specific ankle joint orthoses is becoming increasingly important and can be ideally realized by means of additive manufacturing. However, currently, there are no functional additively manufactured fiber-reinforced products that are used in the field of orthopedic treatment. In this paper, an approach as to how addit...

Mithilfe des am KTmfk entwickelten thermo-elastohydrodynamischen Simulationstools „TriboFEM“ werden am Beispiel von Wälzlagern die Reibung von sekundären Rollenstirn/Ringbord-Kontakten unter Berücksichtigung exakter Geometrien sowie die verschleißbedingte Profiländerung von primären Laufbahnkontakten berechnet. Die Ergebnisse der Simulationen werde...

The calculation of moments of area is one of the most fundamental aspects of engineering mechanics for calculating the properties of beams or for the determination of invariants in different kind of geometries. While a variety of shapes, such as circles, rectangles, ellipses, or their combinations, can be described symbolically, such symbolic expre...

The field of application of data-driven product development is diverse and ranges from requirements through the early phases to the detailed design of the product. The goal is to consistently analyze data to support and improve individual steps in the development process. In the context of this work, the focus is on the design and detailing phase,...