Verification of FEM-model of Dynamic Strain in Bolts During Recoil
(2024) In TFHF-5000 FHLM01 20241Solid Mechanics
Department of Construction Sciences
- Abstract
- When creating finite element simulations, fasteners are often simplified or disregarded even though they are exposed to large loads and are reasons to cause failure in the model. Aimpoint AB produces electronic red dot sights that are exposed to high accelerations of at least 400G. The aim of this degree project is divided into two parts: develop and evaluate a test methodology for measuring strain in bolt during high recoils with the help of embedded strain gauges, and to confirm if finite element simulations of the bolts is a reliable method to verify that they are suited for recoil exposure. The simulations will focus on three different methods of modeling a bolt: a coupled-, a hybrid- and a solid bolt. These will contribute to further... (More)
- When creating finite element simulations, fasteners are often simplified or disregarded even though they are exposed to large loads and are reasons to cause failure in the model. Aimpoint AB produces electronic red dot sights that are exposed to high accelerations of at least 400G. The aim of this degree project is divided into two parts: develop and evaluate a test methodology for measuring strain in bolt during high recoils with the help of embedded strain gauges, and to confirm if finite element simulations of the bolts is a reliable method to verify that they are suited for recoil exposure. The simulations will focus on three different methods of modeling a bolt: a coupled-, a hybrid- and a solid bolt. These will contribute to further development of design choices and dimensioning of fasteners, test development of strain measurements and overall time efficiency for Aimpoint.
The project consists of two studies to reach the goals. The first study is to create a test method to verify the use and behavior of strain gauges, which then leads to the second study of using the strain gauges in recoil tests. The test methodologies for both studies were successful and will contribute to further understanding of testing bolts in high recoil environments with the help of strain gauges. On the other hand, the simulations of the shock tests were not reliable despite which bolt model was used and will require further investigation. The models resulted in strain curves that were two to three times larger than during the experiments. Using the simulations to develop test will give a substantial margin of error that the designs will not be sufficiently tested. With greater knowledge of the simulation program and continued work on the bolt models, there is hope to develop a more reliable simulation. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9157068
- author
- Grövnes, Martina LU
- supervisor
- organization
- course
- FHLM01 20241
- year
- 2024
- type
- H3 - Professional qualifications (4 Years - )
- subject
- publication/series
- TFHF-5000
- report number
- TFHF-5259
- language
- English
- id
- 9157068
- date added to LUP
- 2024-06-17 11:06:57
- date last changed
- 2024-06-17 11:06:57
@misc{9157068,
abstract = {{When creating finite element simulations, fasteners are often simplified or disregarded even though they are exposed to large loads and are reasons to cause failure in the model. Aimpoint AB produces electronic red dot sights that are exposed to high accelerations of at least 400G. The aim of this degree project is divided into two parts: develop and evaluate a test methodology for measuring strain in bolt during high recoils with the help of embedded strain gauges, and to confirm if finite element simulations of the bolts is a reliable method to verify that they are suited for recoil exposure. The simulations will focus on three different methods of modeling a bolt: a coupled-, a hybrid- and a solid bolt. These will contribute to further development of design choices and dimensioning of fasteners, test development of strain measurements and overall time efficiency for Aimpoint.
The project consists of two studies to reach the goals. The first study is to create a test method to verify the use and behavior of strain gauges, which then leads to the second study of using the strain gauges in recoil tests. The test methodologies for both studies were successful and will contribute to further understanding of testing bolts in high recoil environments with the help of strain gauges. On the other hand, the simulations of the shock tests were not reliable despite which bolt model was used and will require further investigation. The models resulted in strain curves that were two to three times larger than during the experiments. Using the simulations to develop test will give a substantial margin of error that the designs will not be sufficiently tested. With greater knowledge of the simulation program and continued work on the bolt models, there is hope to develop a more reliable simulation.}},
author = {{Grövnes, Martina}},
language = {{eng}},
note = {{Student Paper}},
series = {{TFHF-5000}},
title = {{Verification of FEM-model of Dynamic Strain in Bolts During Recoil}},
year = {{2024}},
}