Subjects, Topics, and Anchoring to the Context

The article discusses the connection between the syntactic and semantic properties of weak, strong, and referential DP subjects. In particular, I argue that nominal expressions possess a situation argument and that their interpretation and their distribution follow from the presuppositional requirements that the determiner imposes on the individual argument and situation argument of its complement nominal. These presuppositional requirements, I then argue, are embodied by local relations of the subject to a distinct head in the C domain, Fin(0) in the system of Rizzi 1997, where specific referential values of discourse antecedents are accessible

Mechanisms of origin and classification of out-of-plane fiber waviness in composite materials - a review

Out-of-plane fiber waviness, also referred to as wrinkling, is considered one of the most significant effects that occur in composite materials. It significantly affects mechanical properties, such as stiffness, strength and fatigue and; therefore, dramatically reduces the load-carrying capacity of the material. Fiber waviness is inherent to various manufacturing processes of fiber-reinforced composite parts. They cannot be completely avoided and thus have to be tolerated and considered as an integral part of the structure. Because of this influenceable but in many cases unavoidable nature of fiber waviness, it might be more appropriate to consider fiber waviness as effects or features rather than defects. Hence, it is important to understand the impact of different process parameters on the formation of fiber waviness in order to reduce or, in the best case, completely avoid them as early as possible in the product and process development phases. Mostly depending on the chosen geometry of the part and the specific manufacturing process used, different types of fiber waviness result. In this study, various types of waviness are investigated and a classification scheme is developed for categorization purposes. Numerous mechanisms of wrinkling were analyzed, leading to several recommendations to prevent wrinkle formation, not only during composite processing, but also at an earlier design stage, where generally several influence factors are defined

The interaction between syntax, information structure, and prosody in word order change

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Experimental investigation of the radius forming behavior of fiber reinforced thermoplastics

The following work focuses on the experimental analysis of the forming behavior of fiber reinforced thermoplastic layups with a special focus on the radii. Possible factors influencing the result and quality of the forming shall be investigated. Considered parameters were the thickness of the layups, the fiber orientation, the size of the radius and the preload of the layup. The layups were produced with a Fiberforge RELAY2000® ATL machine and consolidated in a heated hydraulic press as a subsequent step. The consolidated layups were then thermoformed using two matched dies. During the forming, the material was cooled down until it reached a solid state and could be removed from the mold. These test specimens were then analyzed regarding their draping pattern, occurring defects and forming quality using microsections and the optical analysis system ATOS by GOM. The investigations showed that especially the thickness of the layup and the size of the radius had an influence on the part quality. But also the fiber orientation affected the formation of imperfections. The preload of the layup was of less importance for the forming behavior

Direct adhesion of CFR-thermoplast on steel - testing and simulation of the lap shear fracture

In this work a novel joining technology by direct adhesion of carbon fiber-reinforced thermoplastic (CFRTP) with polyamide 6 matrix on steel is investigated. Based on endless fiber-reinforced thermoplastic tapes a unidirectional layup is manufactured with the FiberForge RELAY®. Here, the layup is stacked by ultrasonic welding points and is so far not consolidated to a laminate. Two preforms are positioned into a tooling with a metal sheet in between. Afterwards the joining process is carried out by applying heat and pressure on the tooling. The manufactured hybrid double lap joint specimens are conditioned according to the standard DIN EN ISO 1110. Then, tension tests are performed evaluating different surface treatments on the metal sheet in terms of joint strength. Here, joint strength up to 19 MPa is achieved. Based on these results one of the surface treatments is characterized by DCB and ENF tests to get the energy release rates in Mode I and Mode II, respectively. These values are used as input parameters for the cohesive zone modeling of the interface in Abaqus. Finally the double lap joint tension test is simulated and shows a good correlation with the test result

Application of the time-temperature superposition principle to the mechanical characterization of elastomeric adhesives for crash simulation purposes

In the automotive industry, finite element simulation is widely used to ensure crashworthiness. Mechanical material data over wide strain rate and temperature ranges are required as a basis. This work proposes a method reducing the cost of mechanical material characterization by using the time-temperature superposition principle on elastomeric adhesives. The method is based on the time and temperature interdependence which is characteristic for mechanical properties of polymers. Based on the assumption that polymers behave similarly at high strain rates and at low temperatures, a temperature-dominated test program is suggested, which can be used to deduce strain rate dependent material behavior at different reference temperatures. The temperature shift factor is found by means of dynamic mechanical analysis according to the WLF-equation, named after Williams, Landel and Ferry. The principle is applied to the viscoelastic properties as well as to the failure properties of the polymer. The applicability is validated with high strain rate tests