Ingo Ehrlich

Ostbayerische Technische Hochschule Regensburg | OTH Regensburg · Department of Mechanical Engineering

Most shell or beam models of anisotropic tubes under bending have no validity for thick-walled structures. As a result, the need to develop three-dimensional formulations which allow a change in the stress, strain and displacement distributions across the radial component arises. Basic formulations on three-dimensional anisotropic elasticity were m...

The mechanical properties of additively manufactured plastic components, i. e. strength and stiffness, can limit their use as load-bearing structures. In particular, the use of continuous reinforcing fibers can significantly improve the mechanical properties of additively manufactured components and enable the production of load-bearing fiber compo...

Integrated Structure Health Monitoring System for aircrafts and airborn systems especially for Unmanned Aerial Vehicles

Rohre aus faserverstärktem Kunststoff werden unter anderem in der Elektroindustrie und dem Rohrleitungsbau eingesetzt. Die Gründe dafür sind vielfältig. Speziell Glasfasern bieten neben dem Leichtbaupotential auch sehr gute Isolationseigenschaften. Dabei sind diese Rohre häufig einer Biegebelastung ausgesetzt, dessen Auswirkungen auf die Struktur s...

This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, lami...

Impregnation Technology and Winding Process of Thermoplastic Composite Tubes

Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the varia...

Filament winding is a well-established process for the production of high-end fully wrapped composite circular structures like pressure vessels for gas fuels in automotive and other lightweight applications. Caused by the fact that thermoset matrix systems are easier to process due to their low viscosities compared to thermoplastic matrix systems,...

The aim of this study is to compare two different standardized testing procedures, tensile testing and Mode-I double cantilever beam (DCB) testing, to evaluate a possible correlation between the dominant failure in glass fibre-reinforced plastics and their according acoustic emissions (AE). AE is processed by using a burst collection of all recorde...

The effect of process variables such as shear rate and temperature on the viscosity of polypropylene during the processing of thermoplastic based composites was investigated in this study. The melt impregnation is used in the process of continuous glass fibre reinforced thermoplastic composites. To develop a mathematical model for roving impregnati...

Die Erforschung von faserverstärkten Kunststoffen (FVK) mit thermoplastischer Matrix ist aufgrund der Schweißeignung als Verbindungstechnologie, der thermischen Umformbarkeit, der Recyclebarkeit sowie der verkürzten Prozesszeiten im Vergleich zu den vorwiegend eingesetzten faserverstärkten Duroplasten erstrebenswert. Die Wechselwirkung zwischen den...

This article presents first results of artificial aging experiments by ultraviolet (UV) irradiation on thermoplastic materials conducted as an intent of the research project Thermoplastic Composite Structures (TheCoS) in collaboration of the Ostbayerische Technische Hochschule (OTH) Regensburg and the University of West Bohemia (UWB) in Pilsen as p...

The high melt viscosity and a low heat conduction of thermoplastic materials are the technical reasons, why the production of reinforced thermoplastics is so challenging. A solution is the pin assisted melt impregnation, whose constructive elaboration is illustrated in this poster.The main aim is to create a mathematical model, which is able to giv...

Purpose: A review regarding the acting mechanisms of structural dynamic material damping in fabric reinforced composites is presented. Design/methodology/approach: Mechanical acting principles identified by different investigations are considered. Aspects of the determination and calculation of structural mechanical material properties of fabric re...

Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, s...

A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude...

Filament wound composite structures are widely used in the field of pressure vessels, tubes, pipelines or rocket cases. The mechanical behavior of these structures is typically different from those of flat laminated structures due to an alternating lay-up sequence, winding tension and manufacturing induced imperfections. However, design and analysi...

In this paper, the idea of fiber-oriented repair geometries for carbon fiber reinforced plastics (CFRP) is investigated. It considers the differing mechanical properties of unidirectional fiber reinforced material by excluding overlapping regions perpendicular to the fiber direction of the particular layer. A mechanical and numerical comparison of...

Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influenc...

The Finite Element Analysis (FEA) is an effective tool to save time and costs in the development phase of engineering disciplines. Thus the dimensioning can easily be tested and adapted with a simulation instead of expensive experiments. Manufacturing and testing of fiber-reinforced plastic components is very extensive because of their specific mat...

Nowadays, there are hardly any structures without joints. On this occasion connections of composite materials with metallic components depict a particular challenge in the structural design. Bolted joints pose a significant weak point in the composite structure because of the strength step from composite to metal and the notch effect of the bolt ho...

This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by...

Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscop...

This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. That is the reason...

The determination of the fibre volume content in fibre reinforced plastics is usually done by removing the matrix of a representative specimen after the material has been produced. For the removal of a polymeric matrix system two possibilities exist. The matrix can either be extracted chemically or thermally where the fibre reinforcement must not b...

High quality semi-finished products with reproducible properties of basaltic fibres are hardly available on the market. In order to examine the properties of basalt fibre reinforced plastics high quality specimens are necessary. The fibre volume content and the porosity of the produced specimen are used as the typical criteria to evaluate the achie...

München, Univ. der Bundeswehr, Diss., 2004. Computerdatei im Fernzugriff.