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Articles 14731 - 14760 of 21740
Full-Text Articles in Engineering
Moment Rotation Behavior For Concrete Filled Shs Column To Composite Beam Connections, J. S. Lee, Young Bonb Kwon, K. S. Woo
Moment Rotation Behavior For Concrete Filled Shs Column To Composite Beam Connections, J. S. Lee, Young Bonb Kwon, K. S. Woo
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
A series of connection tests were carried out to study the behavior of connections between concrete filled Square Hollow Section(SHS) columns and composite W-section beams. The test connections were four different semi-rigid types selected for application to multi -story building frames. The initial flexural rigidities were estimated by different theories and compared with the simple beam. Moment-roration relations were simulated using a finite element program and a simple power model was proposed to predict the moment-rotation behavior of connections.
Strength And Stiffness Calculation Procedures For Composite Slabs, Budi R. Widjaja, Samuel W. Easterling
Strength And Stiffness Calculation Procedures For Composite Slabs, Budi R. Widjaja, Samuel W. Easterling
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Two procedures for calculating the strength and stiffness of composite slabs based on a partial interaction model are introduced. The procedures rely on elemental test results for interfacial and end-anchorage behavior, and thus offer an alternate solution to the m and k method that relies heavily on full scale slab tests. Strength calculations made using the new procedures along with calculations from the Steel Deck Institute procedure are compared to a series of full size composite slab test results.
Strength Of Headed Shear Studs In Cold-Formed Steel Deck, John C. Lyons, Samuel W. Easterling, Thomas M. Murray
Strength Of Headed Shear Studs In Cold-Formed Steel Deck, John C. Lyons, Samuel W. Easterling, Thomas M. Murray
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Results from 57 push-out tests of headed shear studs in cold-formed steel deck are presented. The results are compared to predicted strengths using the American Institute of Steel Construction Load and Resistance Factor Design Specification. The results indicate that the AISC specification does not accurately predict the strength of the shear studs placed in steel deck.
Modeling Of Cold-Formed Purlins-Sheeting Systems, S. Kitipornchai, R. M. Lucas, F. G. A. Al-Bermani
Modeling Of Cold-Formed Purlins-Sheeting Systems, S. Kitipornchai, R. M. Lucas, F. G. A. Al-Bermani
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Purlin-sheeting systems used for roofs and walls commonly take the form of cold-formed channel or zed section purlins, screw-connected to corrugated sheeting. This paper presents two nonlinear elasto-plastic finite element models, capable of predicting the behaviour of purlin-sheeting systems without the need for either experimental input or over simplifying assumptions. The first model incorporates both the sheeting and the purlin while the second, a simplified version of the first model, includes only the purlin. Both models are able to account for cross-sectional distortion of the purlin, the flexural and membrane restraining effects of the sheeting, and failure of the purlin …
Residential Applications Of Cold-Formed Structural Members In Australia, Gregory J. Hancock, Thomas M. Murray
Residential Applications Of Cold-Formed Structural Members In Australia, Gregory J. Hancock, Thomas M. Murray
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The design of steel framed houses in Australia is governed by a range of Australian Standards covering materials, strnctural design and performance and loading. The paper describes these standards and their applicability. Innovative building systems using high strength steel have recently been introduced into the residential construction market in Australia. A brief description of the members used in these systems is provided. The National Association of Steel Framed Housing (NASH) promotes the use of steel in homes and provides educational material to assist builders, suppliers, teachers and students.
Steel - The Clear Cut Alternative, Richard Haws
Steel - The Clear Cut Alternative, Richard Haws
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The current use of cold-formed steel owes its success to efforts which started 50 years ago. In 1946 AISI published the first specification for the design of cold-formed (then known as light gage) steel structural members. The specification was the end product of a doctoral thesis by Dr. George Winter which was initiated in 1939. Since 1946 AISI has continually updated and modernized the AISI Specification for the Design of Cold-Formed Steel Structural Members. The 1956 manual was the first design specification to have a companion commentary. In 1991 AISI published the LRFD version of the Design of Cold-Formed Steel …
A Study On The Effect Of Cold Forming On The Yield Strength Of Stainless Steel Type 304 - Hardness Test Approach, M. Macdonald, J. Rhodes, M. Crawford, G. T. Taylor
A Study On The Effect Of Cold Forming On The Yield Strength Of Stainless Steel Type 304 - Hardness Test Approach, M. Macdonald, J. Rhodes, M. Crawford, G. T. Taylor
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper describes a preliininary experimental investigation of the effects of cold forming on the material properties of stainless steel comer sections. The background and theory behind the research is briefly reviewed and is followed by a description of hardness testing. Hardness testing is used to postulate values for the increase in yield strength around the comers. The experimental findings are presented and the postulated increases in yield strength are compared with those predicted by two existing theories, and by other experiments carried out by the authors. It is concluded that the linear relationships found between yield strength and hardness …
An Explicit Approach To Design Of Stainless Steel Columns, Jacques Rondal, Kim J. R. Rasmussen
An Explicit Approach To Design Of Stainless Steel Columns, Jacques Rondal, Kim J. R. Rasmussen
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The paper describes a design procedure for stainless steel columns failing by flexural buckling. In the approach, the stress strain-curve is assumed to be expressed as a Ramberg-Osgood curve, defined in terms of the initial modulus (Eâ‚€), the 0.2% proof stress (σ₀.â‚‚) and the parameter n. It is shown that the column curve can be described in terms of the Ramberg-Osgood parameters by adopting a Perry-curve as basic strength curve and expressing the imperfection paranleter in terms of Eâ‚€, σ₀.â‚‚ and n. By using a Perry-curve, the design procedure is explicit. This contrasts the iterative approach described in the ASCE-LRFD …
Burst Strength Of Type 304l Stainless Steel Tubes Subjected To Internal Pressure And External Forces, J. Pretorius, P. Van Der Merwe, G. J. Van Den Berg
Burst Strength Of Type 304l Stainless Steel Tubes Subjected To Internal Pressure And External Forces, J. Pretorius, P. Van Der Merwe, G. J. Van Den Berg
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The findings of an investigation concerning the burst strength of cold-formed Type 304L stainless steel tubes subjected to internal pressure and static external forces are reported in this study. The use of cold-formed stainless steel longitudinally welded tube in pressurised processes in industry are limited due to the belief that seamless tubes have superior resistance to internal pressure. The primary objective of this study was to experimentally and theoretically describe the failure criteria for thin-walled longitudinally welded Type 304L stainless steel tubes subjected to internal pressure and static external point loads and torsion loads. Due to the diversity of the …
The Strength Of Partially Stiffened Stainless Steel Compression Members, W. Reyneke, G. J. Van Den Berg
The Strength Of Partially Stiffened Stainless Steel Compression Members, W. Reyneke, G. J. Van Den Berg
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
In this study the effect of the non-linear behaviour of stainless steels on the local buckling strength of partially stiffened compression elements is studied. The steel under investigation is a Type 304 stainless steel. Doubly symmetric hat section columns were manufactured by a press braking process and tested as stub columns to exclude overall buckling interaction. The different plasticity reduction factors' suggested in the ASCE stainless steel design specification for stiffened and unstiffened compression elements are used to compare experimental results with theoretical predictions. It is concluded that the ASCE and South African stainless steel design specifications overestimate the local …
Effective Width Of A Simple Edge-Stiffener Subjected To A Stress Gradient, Colin A. Rogers, R. M. Schuster
Effective Width Of A Simple Edge-Stiffener Subjected To A Stress Gradient, Colin A. Rogers, R. M. Schuster
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The most recent editions of the North American Design Standards present a unified effective width approach for the design of compressive elements. This paper outlines a comparison of various modifications to the existing procedure used to calculate the effective width of a simple edge-stiffener subjected to a stress gradient. The comparison involves three methods where the magnitude of the compressive stress is altered, and two stress gradient methods where the plate bucking coefficient is based on the ratio of compressive stresses at the top and bottom of the flat width of the simple edge-stiffener. Analysis of these methods was carried …
The Effects Of Perforation Length On The Behaviour Of Perforated Elements In Compression, J. Rhodes, M. Macdonald
The Effects Of Perforation Length On The Behaviour Of Perforated Elements In Compression, J. Rhodes, M. Macdonald
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The compressional behaviour of stub columns having perforations in the form of slots of different length is examined on the basis of testing. Plain channels of a specified geometry are considered, and the geometry examined follows that of a test programme previously carried out to examine the effects of perforation location on stub column strength. Two different perforation layouts, and two material thicknesses are considered and systematic variation in the slot length is carried out for each layout and thickness. It is found that the stub column compression capacity reduces as the perforation length increases. The test results are compared …
Recent Research And Developments In Cold-Formed Steel Design And Construction, Roger A. Laboube, Wei-Wen Yu
Recent Research And Developments In Cold-Formed Steel Design And Construction, Roger A. Laboube, Wei-Wen Yu
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Golden Anniversary of the AISI Specification - The 1996 AISI Specification - A New AISI Cold-Formed Steel Design Manual - Design of Cold-Formed Steel Stiffened Elements with Multiple Longitudinal Intermediate Stiffeners - A Probablistic Examination of the Ultimate Strength of Cold-Formed Steel Elements - Effective Width of a Simple Edge-Stiffener Subjected to Stress Gradient - The Effects of Perforation Length on the Behaviour of Perforated Elements in Compression - Interaction of Flangel/Edge-Stiffened Cold-Formed Steel C-Sections - Cold-Formed Steel Flat Width Ratio Limits, d/t and d/w - Comparison of the Distortional Buckling Method for Flexural Members with Tests - Design of …
Design Of Cold-Formed Steel Stiffened Elements With Multiple Longitudinal Intermediate Stiffeners, Benjamin W. Schafer, Teoman Pekoz
Design Of Cold-Formed Steel Stiffened Elements With Multiple Longitudinal Intermediate Stiffeners, Benjamin W. Schafer, Teoman Pekoz
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Current specification procedures for calculating the bending strength of members with multiple longitudinal intermediate stiffeners in the compression flange have been found to be inadequate. A new procedure for calculating the effective width of stiffened elements with multiple intermediate stiffeners is presented. The new method introduces the calculation of a buckling coefficient for overall buckling of the entire stiffened element as a unit, and local buckling of the subelement plates between stiffeners. The expression for calculating overall buckling is derived and verified via comparison to numerical methods. The minimum buckling coefficient from the two modes (local and overall) is used …
Cold-Formed Steel Design By Spreadsheet Program, Scott A. Burns
Cold-Formed Steel Design By Spreadsheet Program, Scott A. Burns
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper demonstrates how to use advanced features of a spreadsheet program to design cold-formed steel members efficiently. The example presented in the paper concerns a hat section in flexure which is to be designed for maximum bending strength with a restriction on the total amount of steel that can be used. The nature of the formulas and data entered into the spreadsheet program are presented.
Evaluation And Modelling Of The Material Properties For Analysis Of Cold-Formed Steel Sections, Nabil Abdel-Rahman, K. S. Sivakumaran
Evaluation And Modelling Of The Material Properties For Analysis Of Cold-Formed Steel Sections, Nabil Abdel-Rahman, K. S. Sivakumaran
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The results of two series of experimental investigations to evaluate the mechanical properties and the residual stresses of cold-formed steel (CFS) sections are reported in this paper. These investigations were performed on channel-shaped CFS sections manufactured using cold-roll forming technique. Tensile coupon tests were used to evaluate the mechanical properties at different positions of the channel sections. Electrical resistance strain gauges with an "Electrical Discharge Machining" cutting technique were used to establish the magnitudes and the distributions of residual stresses within the channel sections. Based on the experimental results, appropriate analysis models for the stress-strain relationship, the variation of the …
The Modulus Of Elasticity Of Steel - Is It 200 Gpa?, Mahen Mahendran
The Modulus Of Elasticity Of Steel - Is It 200 Gpa?, Mahen Mahendran
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
In cold-formed steel construction, the use of a range of thin, high strength steels (0.35 mm thickness and 550 MPa yield stress) has increased significantly in recent times. A good knowledge of the basic mechanical properties of these steels is needed for a satisfactory use of them. In relation to the modulus of elasticity, the current practice is to assume it to be about 200 GPa for all steel grades. However, tensile tests of these steels have consistently shown that the modulus of elasticity varies with grade of steel and thickness. It was found that it increases to values as …
Design Of Thin-Walled Beams For Distortional Buckling, C. Jiang, J. Michael Davies
Design Of Thin-Walled Beams For Distortional Buckling, C. Jiang, J. Michael Davies
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The bending behaviour of cold-formed steel beams is far from simple. The double symmetry associated with hot-rolled I-sections is generally uneconomical and the use of thin-walled slender elements means that local buckling of parts of the cross-section in compression may be a significant design factor leading to additional asymmetry of behaviour. Furthermore, the modern tendency to introduce additional folds in order to control local buckling and to produce more favourable global section properties also serves to aggravate the tendency towards distortional buckling. Generalised Beam Theory (GBT) has wide application to the analysis and design of cold-formed beams and can provide …
Buckling Experiments On Hollow Flange Beams With Web Stiffeners, Mahen Mahendran, P. Avery
Buckling Experiments On Hollow Flange Beams With Web Stiffeners, Mahen Mahendran, P. Avery
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
A new cold-formed and resistance welded section known as the Hollow Flange Beam (HFB) has been developed recently in Australia. In contrast to the common lateral torsional buckling mode of I-beams, this unique section comprising two stiff triangular flanges and a slender web is susceptible to a lateral distortional buckling mode of failure involving lateral deflection, twist and cross-section change due to web distortion. This lateral distortional buckling behaviour has been shown to cause significant reduction of the available flexural strength of HFBs. An investigation using finite element analyses and large scale experiments was carried out into the use of …
Deflection Design Of Cold-Formed Rhs Steel Beams, Xiao-Ling Zhao, Kwong-Ping Kiew
Deflection Design Of Cold-Formed Rhs Steel Beams, Xiao-Ling Zhao, Kwong-Ping Kiew
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The moment-deflection results of cold-formed RHS (rectangular hollow section) steel beams are examined. A simple design approach is proposed to account for the effect that material nonlinearity has on deflection. A general expression is also derived to predict the deflection of cold-formed RHS steel beams.
Determination Of Purlin R-Factors Using A Non-Linear Analysis, Catherine J. Rousch, Gregory J. Hancock
Determination Of Purlin R-Factors Using A Non-Linear Analysis, Catherine J. Rousch, Gregory J. Hancock
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
In both Australia and the U.S.A., the design procedure for purlins under wind uplift loading is based on the use of reduction factors (R-factors), which allow for the flexural-torsional or nonlinear twisting behaviour of purlins with screw-fastened sheeting. To date, all R-factors have been determined by testing. However, in the future it may be more efficient to obtain R-factors from numerical models to minimise testing. This paper shows how a numerical model of the twisting behaviour of channel and Z-section purlins can be used to generate R-factors. Comparisons between experimentally determined and numerically based R-factors are made.
Experimental Research On The Behaviour Of Combined Web Crippling And Bending Of Steel Deck Sections, J. G. M. Kerstens, H. H. Snijder, Monique Bakker, H. Hofmeyer
Experimental Research On The Behaviour Of Combined Web Crippling And Bending Of Steel Deck Sections, J. G. M. Kerstens, H. H. Snijder, Monique Bakker, H. Hofmeyer
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
At an interior support, sections of cold-formed steel are subjected to a concentrated load and a bending moment Existing design rules describing the section failure at an interior support are subject to improvement and are not based on the section's physical failure behaviour. In the last decade, several analytical models have been developed that predict the section ultimate concentrated load and directly include the influence of the bending moment, so that an empirical interaction method is not needed. However, the authors believe that these models are correct only for a concentrated load and a small bending moment In practice large …
Flexural Strength Of Cold-Formed Steel Panels Using Structural Grade 80 Of A653 Steel, Shaojie Wu, Wei-Wen Yu, Roger A. Laboube
Flexural Strength Of Cold-Formed Steel Panels Using Structural Grade 80 Of A653 Steel, Shaojie Wu, Wei-Wen Yu, Roger A. Laboube
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Cold-formed steel decks made of the Structural Grade 80 of ASTM A653 steel (formerly ASTM A446 Grade E steel) are currently designed according to the AlSI specification, using 75% of the specified minimum yield strength of the steel or 60 ksi (413.7 MPa), whichever is less, due to the lack of ductility of the steel. To further evaluate the flexural strength of the cold-formed steel decks using such a steel, a total of seventy-two deck panels with hat-shaped sections were designed and tested under simply supported and two-point loading condition. The test results indicated that for the panel specimens with …
Dynamic Performance Of Light Gauge Steel Framed Shear Walls, Reynaud Serrette, Georgi Hall, Hoang Nguyen
Dynamic Performance Of Light Gauge Steel Framed Shear Walls, Reynaud Serrette, Georgi Hall, Hoang Nguyen
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The results of a series of reversed cyclic 4 ft. x 8 ft. (length x height) 15/32-in. plywood and 7/16-in. oriented strand board (OSB) shear wall tests are presented in this paper. The walls were framed with C-shaped 3-1/2 in. 20 gauge (0.036 in.) studs at 24 in. on center. Each wall was subjected to a sequential phase displacement time history at a frequency of 0.67 Hz. Performance of the wall was shown to depend on the type of sheathing material, the strength of the chord studs, and the screw fastener schedule. Although the hysteretic loops were significantly pinched (a …
Stability Of Standing Seam Roof - Purlin Systems, James M. Fisher, Joe N. Nunnery
Stability Of Standing Seam Roof - Purlin Systems, James M. Fisher, Joe N. Nunnery
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Presented in this paper are the design considerations of purlins which support standing seam roofs. To properly design purlins attached to standing seam roofs the AISI Base Test must be conducted. The AISI anchorage equations can be used for standing seam systems provided that it can be shown that the standing seam diaphragm system has sufficient stiffness to meet the requirements of the diaphragm as specified in Section D3.2.1 of the AISI Specification. The stiffness of standing seam roofs can be determined from conventional diaphragm tests. The stiffness and strength of the standing seam diaphragm can be enhanced by the …
The Oligonucleotide Probe Database, Elizabeth Wheeler Alm, Daniel B. Oerther, N. Larsen, David A. Stahl, Lutgarde M. Raskin
The Oligonucleotide Probe Database, Elizabeth Wheeler Alm, Daniel B. Oerther, N. Larsen, David A. Stahl, Lutgarde M. Raskin
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
No abstract provided.
Generation Of Synthetic-Focus Images From Pulse-Echo Ultrasound Using Difference Equations, Daryl G. Beetner, R. Martin Arthur
Generation Of Synthetic-Focus Images From Pulse-Echo Ultrasound Using Difference Equations, Daryl G. Beetner, R. Martin Arthur
Electrical and Computer Engineering Faculty Research & Creative Works
To produce a complete-dataset, pulse-echo image requires a knowledge of the time of flight (TOF) from each source to each sensor in the transducer array for each site to be imaged. Increasing the speed of TOF calculation is important in adaptive-focus schemes. The authors determined TOF more rapidly than via direct calculation by representing TOF surfaces by two-dimensional (2-D), positive-integer-degree polynomials implemented in their forward-difference form. Errors which accumulate due to the use of a difference equation depend on the degree of the polynomial and on the size of the image. The number of bits needed to address echo samples …
Detecting Stress And Fatigue Cracks, Christian J. Huber, R. Zoughi
Detecting Stress And Fatigue Cracks, Christian J. Huber, R. Zoughi
Electrical and Computer Engineering Faculty Research & Creative Works
Discoveries in using open ended rectangular waveguides for microwave surface crack detection and sizing have generated interest. The foundation, potential, advantages and disadvantages of this methodology, developed at the Applied Microwave Nondestructive Testing Laboratory in the Electrical Engineering Department at Colorado State University, are discussed. Microwave techniques in general and this particular approach offer certain unique advantages that can advance the state of the art of fatigue/surface crack detection. The basic features and capabilities of this technique have been theoretically and experimentally investigated these past few years. However, more developmental work is needed to bring this technique from the laboratory …
Effects Of Structural And Kinetic Parameters On The Performance Of Chromatographic Columns Packed With Perfusive And Purely Diffusive Adsorbent Particles, G. A. Heeter, Athanasios I. Liapis
Effects Of Structural And Kinetic Parameters On The Performance Of Chromatographic Columns Packed With Perfusive And Purely Diffusive Adsorbent Particles, G. A. Heeter, Athanasios I. Liapis
Chemical and Biochemical Engineering Faculty Research & Creative Works
A mathematical model describing dynamic adsorption in columns with spherical bidisperse perfusive or spherical bidisperse purely diffusive adsorbent particles is used to study the effects of the structural parameters of the adsorbent particles and of the parameters of the adsorption mechanism on the performance of chromatographic systems involving the adsorption of bovine serum albumin onto anion-exchange porous adsorbent particles. Four structural parameters are studied: the particle diameter, d(p), the macropore void fraction, ε(p), the microparticle diameter, d(m) and the parameter φ which affects the value of the permeability of the adsorbent particle. Two parameters of the adsorption mechanism are studied: …
Recent Developments In Extrusion Freeform Fabrication (Eff) Utilizing Non-Aqueous Gel Casting Formulations, Greg Hilmas, John L. Lombardi, Robert A. Hoffman, Kevin Stuffle
Recent Developments In Extrusion Freeform Fabrication (Eff) Utilizing Non-Aqueous Gel Casting Formulations, Greg Hilmas, John L. Lombardi, Robert A. Hoffman, Kevin Stuffle
Materials Science and Engineering Faculty Research & Creative Works
Extrusion Freeform Fabrication (EFF) was shown to be an extremely versatile method for fabricating Functionally Graded Materials (FGMs) The approach is inexpensive and potentially feasible for grading between any thermodynamically compatible ceramic-metal, ceramic-ceramic, or metal-metal material combination. Several material systems were investigated in this study including alumina-304 stainless steel, zirconia-304 stainless steel, alumina-Inconel 625, zirconiaInconel625, alumina-nickel aluminide, zirconia-nickel aluminide, titanium carbide-InconeI625, titanium diboride-nickel aluminide, and tungsten carbide-nickel aluminide. A controlled gradient was demonstrated between the end members for all of the above compositions. The FGMs were hot pressed to achieve near theoretical densities, providing flexural strengths as high as 1000 …