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Photography for Accident Reconstruction, Product Liability, and Testing

2024-09-17
Many technical projects, most vehicle and component testing, and all accident reconstructions, product failure analyses, and other forensic investigations, require photographic documentation. Roadway evidence disappears, tested or wrecked vehicles are repaired, disassembled, or scrapped, and components can be tested for failure. Photographs are frequently the only evidence that remains of a wreck, or the only records of subjects before or during tests. Making consistently good images during any inspection is a critical part of the evaluation process. 
Technical Paper

Making Modal Analysis Easy and More Reliable – Reference Points Identification by Experimental Prestudy

2024-06-12
2024-01-2931
Though modal analysis is a common tool to evaluate the dynamic properties of a structure, there are still many individual decisions to be made during the process which are often based on experience and make it difficult for occasional users to gain reliable and correct results. One of those experience-based choices is the correct number and placement of reference points. This decision is especially important, because it must be made right in the beginning of the process and a wrong choice is only noticeable by chance in the very end of the process. Picking the wrong reference points could result in incomplete modal analysis outcomes, as it might make certain modes undetectable, compounded by the user's lack of awareness about these missing modes. In the paper an innovative approach will be presented to choose the minimal number of mandatory reference points and their placement.
Technical Paper

Frequency-Based Substructuring for Virtual Prediction and Uncertainty Quantification of Thin-Walled Vehicle Seat Structures

2024-06-12
2024-01-2946
Dynamic substructuring enables the dynamic behavior analysis of intricate systems. In this context, the precise description of individual subsystem interfaces is crucial. Coupling components through virtual points is suitable, especially when it comes to experimental substructuring. The complex contact situations that arise from joint descriptions in thin-walled structures, like those found in vehicle seats, present a challenging task. This investigation aims to visualize the complex coupling of thin-walled structures by applying the virtual point transformation. Individual subsystems are analyzed through experiments and coupled using the Lagrange multiplier frequency-based substructuring to achieve this goal. For validation purposes, a completely assembled vehicle seat has been investigated. Identification of the connecting elements between the substructures is achieved using decoupling techniques.
Technical Paper

Generating Reduced-Order Image Data and Detecting Defect Map on Structural Components Using Ultrasonic Guided Wave Scan

2024-06-01
2024-26-0416
The paper presents a theoretical framework for the detection and first-level preliminary identification of potential defects on aero-structure components by employing ultrasonic-guided wave-based structural health monitoring strategies, systems and tools. In particular, we focus our study on ground inspection using a laser-Doppler scan of the surface velocity field, which can also be partly reconstructed or monitored using point sensors and actuators structurally integrated. Using direct wavefield data, we first question the detectability of potential defects of unknown location, size, and detailed features. Defects could be manufacturing defects or variations, which may be acceptable from a design and qualification standpoint; however, those may cause significant background signal artefacts in differentiating structure progressive damage or sudden failure like impact-induced damage and fracture.
Standard

Nuts, Self-Locking, UNS N07001 730 °C, 1100 MPa, and 1210 MPa Procurement Specification for, Metric

2024-05-09
CURRENT
MA1943C
This procurement specification covers aircraft quality self-locking nuts for wrenching (hex, spline) and anchor (plate, gang channel, shank) types of nuts made from a corrosion and heat-resistant nickel-base alloy of the type identified under the Unified Numbering System as UNS N07001. Tension height nuts having overall length of threaded portion not less than 1.2 times the nominal thread diameter have 1210 MPa minimum tensile strength at room temperature. Shear height nuts having shorter threaded portion have 1100 MPa minimum tensile strength at room temperature. Maximum test temperature of parts is 730 °C.
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