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Papers by Frederick V Lawrence
This Innovations Deserving Exploratory Analysis (IDEA) project sought an improved method of weldi... more This Innovations Deserving Exploratory Analysis (IDEA) project sought an improved method of welding thermite rail welds that would cause a substantial improvement of the thermite-welded rail's fatigue resistance in the base and web region. The fatigue life of thermite rail welds was increased by modifying standard thermite molds to improve their weld toe geometry and to avoid the formation of cold laps at the web-base fillet. The weld-toe flank angle was reduced by modifying the shape of the molds using a refractory molding compound. The improved fatigue resistance of the thermite welds was demonstrated through full-scale 4-point bending fatigue tests. The results of this study indicate that the fatigue resistance of the web and base of thermite rail welds can be improved by: (1) Eliminating cold laps in both the web-base fillet region and in the rail base by making the molds conform perfectly to the rail in these areas; (2) Reducing the flank angle to as small a value as practi...
Journal of the Soil Mechanics and Foundations Division, 1963
This guide for students in TAM224/CEE210 makes extensive use of material from a web site on
SAE Technical Paper Series, 1998
Fatigue and Fracture Mechanics: 29th Volume, 1999
An analytical model for studying roughness-induced crack closure. Nong Chen, Frederick V Lawrence... more An analytical model for studying roughness-induced crack closure. Nong Chen, Frederick V Lawrence Fatigue and fracture mechanics: 29 th, 535-551, 1999. A 2D analytical model of the combined effects of plasticity-induced ...
Offshore Technology Conference, 1995
The fatigue performance of tubular connections can limit the life of offshore constructions. Fati... more The fatigue performance of tubular connections can limit the life of offshore constructions. Fatigue research for the American Petroleum Institute (API) Offshore Tubular Joints Research Centre focused in its first three projects on fatigue design. An examination of design rules in API RP2A and equivalent standards as well as the basic data has defined several areas where API RP2A can be updated to include new design curves and explicit means of determining hot spot stresses. In addition, several suggestions have been made that would introduce new provisions, such as inclusion of other weld improvements besides grinding and a different method of including the effects of cathodic protection in seawater.
The fatigue performance of tubular connections can limit the life of offshore constructions. Fati... more The fatigue performance of tubular connections can limit the life of offshore constructions. Fatigue research for the American Petroleum Institute (API) Offshore Tubular Joints Research Centre focused in its first three projects on fatigue design. An examination of design rules in API RP2A and equivalent standards as well as the basic data has defined several areas where API RP2A can be updated to include new design curves and explicit means of determining hot spot stresses. In addition, several suggestions have been made that would introduce new provisions, such as inclusion of other weld improvements besides grinding and a different method of including the effects of cathodic protection in seawater.
Metallurgical and Materials Transactions B, 1970
Page 1. The Formation of Cell Structures in Fatigued Iron Crystals FREDERICK V. LAWRENCE, JR. AND... more Page 1. The Formation of Cell Structures in Fatigued Iron Crystals FREDERICK V. LAWRENCE, JR. AND RUSSEL C. JONES Single crystals of c~-Fe have been fatigued in constant stress amplitude reversed plane bend-ing. ...
Journal of Constructional Steel Research, 1989
Abstract The fatigue strength of constructional steel weldments is predicted using a Monte Carlo ... more Abstract The fatigue strength of constructional steel weldments is predicted using a Monte Carlo simulation which estimates the mean fatigue strength and its expected uncertainty at long lives. The underlying analytical model is at present solely based on fatigue crack initiation and early crack growth and is restricted to long-life applications. Several different kinds of fatigue variables are considered: applied or induced bending stresses, notch severity, notch-root residual stresses, and notch-root mechanical properties. Each of the fatigue variables is treated as a random variable, and its uncertainty is modeled by an appropriate probability distribution function based on laboratory observations. Simulations of constructional steel weldment fatigue strength are compared with laboratory test results on cruciform weldments and similar recent fatigue data reported in the literature. The Monte Carlo simulation also permits one to estimate the contribution of each fatigue variable to the overall uncertainty in fatigue strength and thus determine the economic merits of reducing the uncertainty in any one of the fatigue variables to improve the design fatigue strength.
Fatigue & Fracture of Engineering Materials and Structures, 1992
Skip to Main Content. ...
Fatigue & Fracture of Engineering Materials and Structures, 1993
As-cast specimens and smooth specimens of a AA 319 cast aluminum alloy containing casting porosit... more As-cast specimens and smooth specimens of a AA 319 cast aluminum alloy containing casting porosity were fatigue tested with special attention given to the long-life region (N < 1.25 x lo8 cycles). Fatigue cracks were observed to initiate from the near-surface casting pores or from discontinuities resulting from the as-cast surface texture. The observed fatigue lives were strongly dependent on the size (6) of these casting defects. The effect of casting defects on the fatigue life was modeled assuming the fatigue life to be the sum of the crack nucleation and the crack propagation life (including both the growth of short and long cracks). The crack growth behavior of (mechanically) short cracks was considered in detail by a developed crack-closure-at-a-notch (CCN) model. The CCN model predicted the fatigue lives for both as-cast and machine-notched specimens. Extension of the CCN model to reliability-based design was attempted using the measured size distribution of the fatigue-initiating casting pores. NOMENCLATURE a = D + x b = fatigue strength exponent for smooth specimen C, m (C', m') = constants for the relationship of da/dN versus AK (AK,,) D = notch depth: for edge notch, D is the full notch length K,, K,, = gross and net-section elastic stress concentration factor AKeR = effective stress intensity factor range AK, = intersection point of low AK region and high AK region AKIho (AKcR,tho) = long crack threshold intensity factor range (effective value) Lo = intrinsic crack length (mm) JASON C. TING and FKEDEKICK V. LAWRENCE P R (. y) = a model for effective stress intensity ratio for cracks in a notched specimen W = diameter of a cylindrical bar .Y* = spatial extent of notch stress field .Y, I, =crack length, and initial crack length xi = final crack length at failure p = radius of notch root Y (x) = geometry factor for stress intensity factor = fatigue strength coefficient for smooth specimen
Cement and Concrete Research, 1977
Advances in fatigue lifetime predictive …, 1996
Page 124. Chien-Yung Hou1 and Frederick V. Lawrence2 A Crack-Closure Model for the Fatigue Behavi... more Page 124. Chien-Yung Hou1 and Frederick V. Lawrence2 A Crack-Closure Model for the Fatigue Behavior of Notched Components REFERENCE: Hou, C.-Y. and Lawrence, FV," A Crack-Closure Model for the Fa-tigue Behavior ...
Fatigue & Fracture of Engineering Materials and Structures, 1993
A model is proposed to estimate the threshold stress range of a notched component. The model cons... more A model is proposed to estimate the threshold stress range of a notched component. The model considers the variation of crack closure with crack length in the presence of a notch. The threshold stress range was found from the condition that the minimum value of effective threshold stress intensity range of a crack emanating from a notch equals the effective threshold stress intensity range of a "long" crack. The effects of notch depth, of notch acuity, of notch and specimen type, of load ratio, and of material properties on the threshold stresses were considered. Experimental data reported in the literature were used to assess the validity of the model. It was found that the model correctly predicts the behavior of cracks in notched components. NOMENCLATURE D = Notch depth: for edge notch, D is the full notch length, and for centered notch D is half of notch length E = Elastic modulus H = Plastic modulus K,, K, = Fatigue notch factor at the threshold condition (gross and net-section) 4, Km = Gross and net-section elastic stress concentration factor AK = Stress intensity factor range
This Innovations Deserving Exploratory Analysis (IDEA) project sought an improved method of weldi... more This Innovations Deserving Exploratory Analysis (IDEA) project sought an improved method of welding thermite rail welds that would cause a substantial improvement of the thermite-welded rail's fatigue resistance in the base and web region. The fatigue life of thermite rail welds was increased by modifying standard thermite molds to improve their weld toe geometry and to avoid the formation of cold laps at the web-base fillet. The weld-toe flank angle was reduced by modifying the shape of the molds using a refractory molding compound. The improved fatigue resistance of the thermite welds was demonstrated through full-scale 4-point bending fatigue tests. The results of this study indicate that the fatigue resistance of the web and base of thermite rail welds can be improved by: (1) Eliminating cold laps in both the web-base fillet region and in the rail base by making the molds conform perfectly to the rail in these areas; (2) Reducing the flank angle to as small a value as practi...
Journal of the Soil Mechanics and Foundations Division, 1963
This guide for students in TAM224/CEE210 makes extensive use of material from a web site on
SAE Technical Paper Series, 1998
Fatigue and Fracture Mechanics: 29th Volume, 1999
An analytical model for studying roughness-induced crack closure. Nong Chen, Frederick V Lawrence... more An analytical model for studying roughness-induced crack closure. Nong Chen, Frederick V Lawrence Fatigue and fracture mechanics: 29 th, 535-551, 1999. A 2D analytical model of the combined effects of plasticity-induced ...
Offshore Technology Conference, 1995
The fatigue performance of tubular connections can limit the life of offshore constructions. Fati... more The fatigue performance of tubular connections can limit the life of offshore constructions. Fatigue research for the American Petroleum Institute (API) Offshore Tubular Joints Research Centre focused in its first three projects on fatigue design. An examination of design rules in API RP2A and equivalent standards as well as the basic data has defined several areas where API RP2A can be updated to include new design curves and explicit means of determining hot spot stresses. In addition, several suggestions have been made that would introduce new provisions, such as inclusion of other weld improvements besides grinding and a different method of including the effects of cathodic protection in seawater.
The fatigue performance of tubular connections can limit the life of offshore constructions. Fati... more The fatigue performance of tubular connections can limit the life of offshore constructions. Fatigue research for the American Petroleum Institute (API) Offshore Tubular Joints Research Centre focused in its first three projects on fatigue design. An examination of design rules in API RP2A and equivalent standards as well as the basic data has defined several areas where API RP2A can be updated to include new design curves and explicit means of determining hot spot stresses. In addition, several suggestions have been made that would introduce new provisions, such as inclusion of other weld improvements besides grinding and a different method of including the effects of cathodic protection in seawater.
Metallurgical and Materials Transactions B, 1970
Page 1. The Formation of Cell Structures in Fatigued Iron Crystals FREDERICK V. LAWRENCE, JR. AND... more Page 1. The Formation of Cell Structures in Fatigued Iron Crystals FREDERICK V. LAWRENCE, JR. AND RUSSEL C. JONES Single crystals of c~-Fe have been fatigued in constant stress amplitude reversed plane bend-ing. ...
Journal of Constructional Steel Research, 1989
Abstract The fatigue strength of constructional steel weldments is predicted using a Monte Carlo ... more Abstract The fatigue strength of constructional steel weldments is predicted using a Monte Carlo simulation which estimates the mean fatigue strength and its expected uncertainty at long lives. The underlying analytical model is at present solely based on fatigue crack initiation and early crack growth and is restricted to long-life applications. Several different kinds of fatigue variables are considered: applied or induced bending stresses, notch severity, notch-root residual stresses, and notch-root mechanical properties. Each of the fatigue variables is treated as a random variable, and its uncertainty is modeled by an appropriate probability distribution function based on laboratory observations. Simulations of constructional steel weldment fatigue strength are compared with laboratory test results on cruciform weldments and similar recent fatigue data reported in the literature. The Monte Carlo simulation also permits one to estimate the contribution of each fatigue variable to the overall uncertainty in fatigue strength and thus determine the economic merits of reducing the uncertainty in any one of the fatigue variables to improve the design fatigue strength.
Fatigue & Fracture of Engineering Materials and Structures, 1992
Skip to Main Content. ...
Fatigue & Fracture of Engineering Materials and Structures, 1993
As-cast specimens and smooth specimens of a AA 319 cast aluminum alloy containing casting porosit... more As-cast specimens and smooth specimens of a AA 319 cast aluminum alloy containing casting porosity were fatigue tested with special attention given to the long-life region (N < 1.25 x lo8 cycles). Fatigue cracks were observed to initiate from the near-surface casting pores or from discontinuities resulting from the as-cast surface texture. The observed fatigue lives were strongly dependent on the size (6) of these casting defects. The effect of casting defects on the fatigue life was modeled assuming the fatigue life to be the sum of the crack nucleation and the crack propagation life (including both the growth of short and long cracks). The crack growth behavior of (mechanically) short cracks was considered in detail by a developed crack-closure-at-a-notch (CCN) model. The CCN model predicted the fatigue lives for both as-cast and machine-notched specimens. Extension of the CCN model to reliability-based design was attempted using the measured size distribution of the fatigue-initiating casting pores. NOMENCLATURE a = D + x b = fatigue strength exponent for smooth specimen C, m (C', m') = constants for the relationship of da/dN versus AK (AK,,) D = notch depth: for edge notch, D is the full notch length K,, K,, = gross and net-section elastic stress concentration factor AKeR = effective stress intensity factor range AK, = intersection point of low AK region and high AK region AKIho (AKcR,tho) = long crack threshold intensity factor range (effective value) Lo = intrinsic crack length (mm) JASON C. TING and FKEDEKICK V. LAWRENCE P R (. y) = a model for effective stress intensity ratio for cracks in a notched specimen W = diameter of a cylindrical bar .Y* = spatial extent of notch stress field .Y, I, =crack length, and initial crack length xi = final crack length at failure p = radius of notch root Y (x) = geometry factor for stress intensity factor = fatigue strength coefficient for smooth specimen
Cement and Concrete Research, 1977
Advances in fatigue lifetime predictive …, 1996
Page 124. Chien-Yung Hou1 and Frederick V. Lawrence2 A Crack-Closure Model for the Fatigue Behavi... more Page 124. Chien-Yung Hou1 and Frederick V. Lawrence2 A Crack-Closure Model for the Fatigue Behavior of Notched Components REFERENCE: Hou, C.-Y. and Lawrence, FV," A Crack-Closure Model for the Fa-tigue Behavior ...
Fatigue & Fracture of Engineering Materials and Structures, 1993
A model is proposed to estimate the threshold stress range of a notched component. The model cons... more A model is proposed to estimate the threshold stress range of a notched component. The model considers the variation of crack closure with crack length in the presence of a notch. The threshold stress range was found from the condition that the minimum value of effective threshold stress intensity range of a crack emanating from a notch equals the effective threshold stress intensity range of a "long" crack. The effects of notch depth, of notch acuity, of notch and specimen type, of load ratio, and of material properties on the threshold stresses were considered. Experimental data reported in the literature were used to assess the validity of the model. It was found that the model correctly predicts the behavior of cracks in notched components. NOMENCLATURE D = Notch depth: for edge notch, D is the full notch length, and for centered notch D is half of notch length E = Elastic modulus H = Plastic modulus K,, K, = Fatigue notch factor at the threshold condition (gross and net-section) 4, Km = Gross and net-section elastic stress concentration factor AK = Stress intensity factor range