Engineering Commons^™

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …

Life Cycle Energy Assesment Of Advanced Fiber Reinforced Composite Design And Manufacturing Methodologies, Urjit Lad

All Theses

Automotive industry at large is focused on vehicle light-weighting since a 6%-8% increase in fuel efficiency can be achieved with a 10% reduction in vehicle weight [1]. With the growing demand for cost-effective and sustainable light weighting of automobile structures, interest has increased in the application of fiber reinforced plastic (FRP) composites for use in the Body-in-White (BiW), which can account for up to 40% of the total vehicle weight. Traditional FRP composite manufacturing processes like vacuum assisted resin transfer molding, autoclave consolidation or use of automated fiber placement have been successfully used for marine and aerospace applications. However, these …

Effect Of Autoclave Process Parameters On Mechanical Behaviors Of Carbon Fiber Reinforced Polymer Composites Fabricated Via Additive Manufacturing, Quang Hao Nguyen

Honors Undergraduate Theses

Additively manufactured carbon fiber reinforced polymers (CFRP) are vastly studied for their remarkable mechanical properties compared to most other 3D printed materials. Different methods were employed to further increase mechanical performance of CFRP 3D printed parts. The objective of the study is to investigate the effect of autoclave postprocessing on the interlaminar shear behavior between 3D printed CFRP layers. 3D printed CFRP samples were processed with nine combinations of temperature and vacuum in an autoclave. Short beam shear (SBS) tests were performed to characterize the interlaminar shear strength (ILSS) of the samples after autoclave processing. Digital image correlation (DIC) was …

Post-Processing And Characterization Of Additive Manufactured Carbon Fiber Reinforced Semi-Crystalline Polymers, Patricia Revolinsky

Mechanical & Aerospace Engineering Theses & Dissertations

The aim of this work is to study the effect of post-processing on additive manufactured (AM) continuous carbon fiber reinforced plastics (CFRPs) performance. As-printed AM CFRPs do not perform as well as conventionally manufactured CFRPs with the same composition. Possible improvements to AM CFRP performance include annealing and applying uniaxial pressure with elevated temperature. Samples were subjected to pressure and temperature treatments and annealing at a constant temperature. Treated materials were subjected to three-point bending tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to characterize and assess sample performance. Results were assessed for flexural strength, …

Numerical And Experimental Study Of Machining Process Of High Strength Lightweight Materials, Chao Zhang

All Dissertations

No abstract provided.

Design And Analysis Of One-Piece 10” Carbon Fiber Wheels For Zips Racing Zr20 Formula Sae Racecar, Patrick Kruse, Henry J. Wathen, Jordan J. Hyde, Nicholas D. Dobben, Jordan D. Blake

Williams Honors College, Honors Research Projects

Reducing the weight of a vehicle in racing can substantially improve the vehicle dynamics and general performance capabilities. More specifically, the reduction of the unsprung corner weight can provide noticeable performance gains in handling and responsiveness, leading to a quicker, more agile car due to a lower yawing moment of inertia. Unsprung weight reduction also improves the car’s ability to maintain contact between the tires and the road surface for a more consistent grip. In this project we identified the loads that act on the wheel rims according to the data collected from the sensors in the car’s suspension, and …

Formula Sae Monocoque Chassis Development, Kc Egger, Brian Ford, Kyle Nagao, Neal Sharma, Donovan Zusalim

Mechanical Engineering

Formula SAE is a collegiate competition hosted by SAE International with the primary goal being to design, manufacture, and race an open wheel race car. The Cal Poly Racing Formula SAE team strives for improvement every race season and has remained competitive as a result. The 2019-2020 management team determined that further research and development towards the chassis would yield the greatest performance benefit for future seasons, as the previous chassis platform limited packaging and mounting options for vehicle subsystems which interfaced with the chassis.

A redesign of the Cal Poly Racing Formula SAE team’s carbon fiber reinforced polymer monocoque …

Comparative Analysis And Dynamic Response Of Garolites Under Temperature Spectrum Using Low Velocity Impact Test, Birendra Chaudhary

Honors Theses

The purpose of this study was to examine the dynamic response of three different grades of garolites under the temperature spectrum. High-Temperature G-11 Sheet (HTG), Impact Resistance Garolite E-glass (HIG), and Economical Garolite (EG) were tested using an Instron Dynatup 8250 impact tester. Three specimens were used for all three composites and were tested at 6 different temperatures, -10^oC, 25^oC, 50^oC, 100^oC, 150^oC and 200^oC using the Low-Velocity Impact Machine with 20 Kip punch shear load cell. The results showed that HIG had the highest resistance to punch …

Propagating, Evanescent, And Complex Wavenumber Guided Waves In High-Performance Composites, Victor Giurgiutiu, Mohammad Faisal Haider

Faculty Publications

The study of propagating, evanescent and complex wavenumbers of guided waves (GWs) in high-performance composites using a stable and robust semi-analytical finite element (SAFE) method is presented. To facilitate understanding of the wavenumber trajectories, an incremental material change study is performed moving gradually from isotropic aluminum alloy to carbon fiber reinforced polymer (CFRP) composites. The SAFE results for an isotropic aluminum alloy plate are compared with the exact analytical solutions, which shows that N = 20 SAFE elements across the thickness provides

Propagating, Evanescent, And Complex Wavenumber Guided Waves In High-Performance Composites, Victor Giurgiutiu, Mohammad Faisal Haider

Faculty Publications

The study of propagating, evanescent and complex wavenumbers of guided waves (GWs) in high-performance composites using a stable and robust semi-analytical finite element (SAFE) method is presented. To facilitate understanding of the wavenumber trajectories, an incremental material change study is performed moving gradually from isotropic aluminum alloy to carbon fiber reinforced polymer (CFRP) composites. The SAFE results for an isotropic aluminum alloy plate are compared with the exact analytical solutions, which shows that N = 20 SAFE elements across the thickness provides <0.5% error in the highest evanescent wavenumber for the given frequency-wavenumber range. The material change study reveals that reducing the transverse and shear moduli moves the wavenumber solution towards one similar to composite material. The comparison of the propagating, evanescent and complex wavenumber trajectories between composites and aluminum alloy show that antisymmetric imaginary Lamb wave modes always exist in composites although they may not exist in isotropic aluminum alloy at some frequencies. The wavenumber trajectories for a unidirectional CFRP plate show that the range of real wavenumber is much smaller than in the isotropic aluminum alloy. For laminated CFRP composite plates (e.g., unidirectional, off-axis, transverse, cross-ply and quasi-isotropic laminates), the quasi Lamb wave and shear horizontal (SH) wave trajectories are also identified and discussed. The imaginary SH wave trajectories in laminated composites are distorted due to the presence of ±45 plies. The convergence study of the SAFE method in various CFRP laminates indicates that sufficient accuracy can always be achieved by increasing the number of SAFE elements. Future work will address the stress-continuity between composite layers.

Investigation Of Drilling Performance In Cryogenic Drilling On Cfrp Composite Laminates, Tian Xia

Theses and Dissertations--Mechanical Engineering

In recent years, there has been a substantial growth in the application of carbon fiber reinforced plastic (CFRP) composite materials in automobile and aerospace industries due to their superior properties such as lightweight, high strength, excellent corrosion resistance, and minimal fatigue concerns. The present study evaluates the drilling performance of woven carbon fiber reinforced plastics under both dry and cryogenic cooling conditions using uncoated solid carbide drill with a through-hole for coolant application.

The effects of the cooling conditions and the cutting parameters on drilling performance in drilling CFRP were evaluated in terms of generated thrust force, torque, cutting edge …

Diffuse Ultrasonic Scattering In Advanced Composites, Christer Stenström

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Non destructive testing (NDT) is a noninvasive technique used for characterization and inspection of the integrity of objects. NDT is an important tool for research, manufacturing monitoring and in-service inspections. Ultrasonic testing is the most used NDT technique, which for advanced composites can identify several types of defects, like delamination and interlaminar cracks. Diffuse ultrasonics has shown to be able to extract information at the microscale of metals and therefore it is believed it can be used for advanced composites to extract microstructural information, i.e. at the level of fibers.

In this thesis, diffuse ultrasonic methods, together with spatial variance …