Current Search: Thermal stresses (x)
View All Items
(1 - 5 of 5)
- Title
- Debonding failure analysis of overmolded pad array carrier (OMPAC) integrated circuit packages.
- Creator
- Hunt, Stephen Douglas., Florida Atlantic University, Carlsson, Leif A.
- Abstract/Description
-
Recently developed electronic packages called Overmolded Pad Array Chip Carrier (OMPAC) IC packages frequently fail at the interface between the overmold compound and the substrate. In this study, this generic type of structure was evaluated by a combination of experimental and analytical methods. Model specimens representative of OMPAC structures were designed, manufactured and tested to failure. Detailed finite element models of the specimens were developed and analyses conducted to...
Show moreRecently developed electronic packages called Overmolded Pad Array Chip Carrier (OMPAC) IC packages frequently fail at the interface between the overmold compound and the substrate. In this study, this generic type of structure was evaluated by a combination of experimental and analytical methods. Model specimens representative of OMPAC structures were designed, manufactured and tested to failure. Detailed finite element models of the specimens were developed and analyses conducted to calculate debond stresses. Analytical methods were refined to include the effect of stress singularities. Stress results were averaged over a distance of.010 in. around the stress singularities to capture the intensity of the stress. These results were used in a combined stress failure criterion to calculate interfacial strengths based on macroscopic failure loads. The interfacial strengths were found to approach, but not exceed, those of the bulk overmold compound.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14778
- Subject Headings
- Thermal stresses, Integrated circuits
- Format
- Document (PDF)
- Title
- Combined influence of heat treatment and immersion corrosion on the tensile-shear strength of aluminum-steel explosively welded plates.
- Creator
- Oberle, Hugues., Florida Atlantic University, McIntyre, Jack F., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A series of experiments were performed on aluminum-steel explosively welded joints. The pub of this research was to better understand the synergism, if any, between thermal heat treatments and exposure to a seawater environment on the tensile-shear strength of the explosively welded joint. The effect of three different heat treatments on the tensile-shear strength of the bond was examined. The combined effect of two heat treatments and immersion in flowing aerated, natural seawater has been...
Show moreA series of experiments were performed on aluminum-steel explosively welded joints. The pub of this research was to better understand the synergism, if any, between thermal heat treatments and exposure to a seawater environment on the tensile-shear strength of the explosively welded joint. The effect of three different heat treatments on the tensile-shear strength of the bond was examined. The combined effect of two heat treatments and immersion in flowing aerated, natural seawater has been studied for two different corrosion times. For comparison purposes, some samples were also immersed in stagnant, aerated 3.5% weight NaCl solution. Open circuit potential measurements and microhardness profiles were also made. It was found that a heat treatment that would anneal the aluminum without causing the formation of an intermetallic layer at the aluminum steel explosively welded interface, was the best compromise between reduced mechanical properties and improved corrosion resistance.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14768
- Subject Headings
- Steel-aluminum alloys, Thermal stresses, Welded joints--Testing
- Format
- Document (PDF)
- Title
- Thermal modeling and field temperature measurement of segmental box girder bridges in Florida.
- Creator
- Basole, Milind Madhukar., Florida Atlantic University, Reddy, Dronnadula V.
- Abstract/Description
-
Temperature and thermal stress variations in a segmental box girder bridge arc studied. A finite element model using the general finite element software MARC is used to predict temperature and thermal stress variation, for segmental box girder bridges. The predictions are compared with actual measured temperature data of two segmental box girder bridges, instrumented with thermocouples and vibrating wire strain gages, in Davie, Florida. Continuous monitoring was carried out for two months in...
Show moreTemperature and thermal stress variations in a segmental box girder bridge arc studied. A finite element model using the general finite element software MARC is used to predict temperature and thermal stress variation, for segmental box girder bridges. The predictions are compared with actual measured temperature data of two segmental box girder bridges, instrumented with thermocouples and vibrating wire strain gages, in Davie, Florida. Continuous monitoring was carried out for two months in July-August, 1991, and for one month in January-February, 1992. Comparison are also made with the NCHRP suggested profiles. A Monte Carlo analysis is performed to accommodate the probabilistic variation of ambient temperature conditions.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14840
- Subject Headings
- Bridges, Box girder, Bridges--Florida, Thermal stresses
- Format
- Document (PDF)
- Title
- Thermal response in Florida bridges.
- Creator
- Sandepudi, Krishna Srinivasa., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Reinforced and prestressed concrete bridges are subjected to non-linear temperature variations leading to complex thermal stresses which vary continuously with time. Though these stresses are often comparable with those produced by live and dead loads, little guidance is given in bridge design codes on how these stresses are accurately computed. The objective of this project is to study the response of Florida bridges in the extreme thermal environment The project is divided into the...
Show moreReinforced and prestressed concrete bridges are subjected to non-linear temperature variations leading to complex thermal stresses which vary continuously with time. Though these stresses are often comparable with those produced by live and dead loads, little guidance is given in bridge design codes on how these stresses are accurately computed. The objective of this project is to study the response of Florida bridges in the extreme thermal environment The project is divided into the following four tasks i) Computer modeling of the bridge and estimation of the thermal response. ii) Field measurements of temperatures in typical bridges. iii) Comparison of observed and estimated data. iv) Suggestions and/or revisions to the existing thermal stress allowances in the code. A computer software FETAB was used to model and analyze the thermal response of several bridge cross sections. Two single cell box girder bridges, located at the 1-595 and US-441 interchange, Fort Lauderdale, were instrumented with thermocouples and vibrating wire strain gages. The predicted temperature variations were found to compare fairly well with those measured in the field. Though the analytical values vary a little from the actual field data, emphasis was given to gain insight into the problems associated with the thermal effects in concrete bridges. Suggestions were made for revision of existing design code provisions for improved design of bridges.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14759
- Subject Headings
- Bridges, Concrete--Thermal properties, Bridges, Concrete--Effect of temperature on, Thermal stresses
- Format
- Document (PDF)
- Title
- The impacts of nest microenvironment on sea turtle hatchling performance and their responses to thermal stress.
- Creator
- Seaman, Heather A., Milton, Sarah, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
As climate change threatens with sea-level rise and more storms, increased erosion could increase the need for beach nourishment. Alterations to sand characteristics may result in changes to the sea turtle nest microenvironment, impacting the temperature and oxygen levels which may affect hatchling performance. In this study, leatherback, loggerhead, and green nests were sampled from two sites with different sand characteristics in Juno Beach, Florida, USA. Gas exchange was higher in green...
Show moreAs climate change threatens with sea-level rise and more storms, increased erosion could increase the need for beach nourishment. Alterations to sand characteristics may result in changes to the sea turtle nest microenvironment, impacting the temperature and oxygen levels which may affect hatchling performance. In this study, leatherback, loggerhead, and green nests were sampled from two sites with different sand characteristics in Juno Beach, Florida, USA. Gas exchange was higher in green turtle nests with a greater mixture of sediment. Darker sediment elevated nest temperatures. Finer sediment and a greater mixture of sediment in leatherback nests elevated the nest temperatures; conversely finer sediment, and a greater mixture of sediment decreased loggerhead and green nest temperatures. Elevated nest temperatures reduced leatherback, loggerhead, and green turtle hatchling performance. Understanding the relationships between beach composition, nest environment, and hatchling performance will aid management decisions essential to sea turtle conservation.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013542
- Subject Headings
- Sea turtles--Nests, Thermal stress (Biology), Sea turtles--Conservation, Beach nourishment
- Format
- Document (PDF)
