professor ben schafer's thin-walled structures research group - johns hopkins university

 

PAST ARTICLES

 

The Best Offense is a Good Defense

(August 2011)

    This summer three students from the group have succesfully defended their Ph.D.'s! Congratulations to Luiz Vieira, Zhanjie Li, and Vahid Zeinoddini. Each of these students has left an incredible legacy for the rest of the group and provided important improvements for thin-walled, particularly cold-formed steel, structures. Turn back to this page for more updates on their efforts.

 

See us at upcoming conferences

(April 2011)

    The late spring/summer conference season is about to get underway and the Thin-walled Structures Group has papers at a number of upcoming conferences that we hope to see some of you at: The Annual Structural Stability Research Council Conference held in conjunction with NASCC in Pittsburgh May 10-13, the ASCE Engineering Mechanics Institute Conference in Boston June 2-4, the NEES Annual Meeting in Buffalo June 9-11.. AISC meetings in late June, AISI meetings in July, and Eurosteel at the end of the summer. Hope to see you there!

 

Help Beta test CUFSM 4

(September 2010)

    We have just completed the first public version of CUFSM 4, now availabe in matlab version only for beta testing. CUFSM 4.03 provides a sweeping expansion to the capabilities of our popular finite strip program - now the local, distortional, and global buckling loads of thin-walled members can be explored for general end boundary conditions. This expansion allows for much more difficult problems to be explored providing new insights for researchers and engineers. Currently we are beta testing the version and plan on releasing a compiled standalone version later this Fall. For more on CUFSM 4 go here, for more on FSM research go here.

AISI COS and COFS meetings

(July 2010)

    The July AISI COS and COFS meetings included a significant amount of work from our research team. Graduate Student Yared Shifferaw's ballot on DSM inelastic bending reserve was approved for the next edition of the Spec. Former student Cris Moen's research on DSM for members with holes was approved by the subcommittee and now goes to the main committee. Recent research on CFS sheathed walls by graduate student Luiz Vieira was discussed at length and received accolades - impact for the Spec. is forthcoming. Recent work by new graduate student Alireza Novajan on web crippling and undergraduate Hannah Blum on bracing was also well received. Additional research on CFS earthquake engineering, and a variety of other topics were also lead by the Thin-walled Structures team.

 

 

SSRC Conference in Orlando 2010

the group and friends, SSRC Conf., May 2010

(group members are making the universal sign of the CFS lipped channel)

SSRC Conference in Orlando

(May 2010)

    The 2010 Annual Stability Council of the Structural Stability Research Council (SSRC) recently completed. Graduate Student Mina Seif presented on DSM extensions for hot-rolled steel. Graduate Student Yared Shifferaw presented recent work on beam-columns and on sheathed CFS walls. Graduate Student Luiz Vieira presented on sheathed CFS walls. Graduate student Zhanjie Li presented on the latest developments with the Finite Strip Method. Former student and now Asst. Prof. Cris Moen presented on DSM methods for members with holes and DSM for members in shear (Moen's research page). and Prof. Schafer stepped in for former student now Asst. Prof. Cheng Yu for his research on CFS shear walls (Cheng was unable to attend due to the birth of his new baby - congrats Cheng!).  In addition the annual meeting of the SSRC was organized by Professor Schafer and complete reports have been posted on the SSRC website.   

 

AISI Sheathing Braced Design Reports

(March 2010)

    The behavior of cold-formed steel wall studs in compression with different types of sheathing attached can be complicated. Test reports on recently completed experiments on single columns and full walls are now available on the Sheathing Braced Design of Wall Studes project page. Recent report from the February 2010 AISI meetings now uploaded as well.  

 

New - "in-house" tools added

(July 2009)

    Our research group uses a number of in-house tools to generate ABAQUS models, post-process and the like. For the first time we are starting to make these tools available to all researchers. Hope you find them helpful in your own analysis.

 

MBMA Workshop on the AISI Spec.

(July 2009)

    A new 1/2 day workshop on the latest developments in the AISI Specification was provided to MBMA members recently, the online materials are available here.

 

ClarkWestern DSM Workshop

(May 2009)

    A new 1 day workshop on the Direct Strength Method was developed for ClarkWestern, the online materials are available here.

 

FSM for general boundary conditions

(May 2009)

    Our research on the finite strip method (FSM) continues, the most recent work provides computationally efficient means to handle general boundary conditions in the finite strip method as discussed in the new web page on research related to extending FSM and developing constrained FSM.

 

AISI Committee on Framing Standards

(April 2009)

    Research from the project on sheathing braced design of wall studs was reported and discussed at the recent AISI Committee on Framing Standards meeting in Madison Wisconsin. Highlights included recent work on fastener stiffness in wall stud systems and single and full wall testing on related systems. (see slides).   

 

 

the group and friends, SSRC Conf., March 2009

(L to R back row: Ben, Don W, Dinar C, Vahid, Zhanjie, Cris
L to R front row: Mina, Yared, Iraj M., Luiz)

SSRC Conference in Phoenix

(March 2009)

    The 2009 Annual Stability Council of the Structural Stability Research Council (SSRC) recently completed. Graduate student Mina Seif presented his recent findings on strength of locally slender structural steel cross-sections and former student. now Asst. Prof., Cris Moen presented on global buckling of members with holes. In addition the annual meeting of the SSRC was organized by Professor Schafer and complete reports have been posted on the SSRC website.   

 

Component performance of stud-sheathing assemblies: new tests and report
(April 2009)

    As part of an ongoing project on the behavior of cold-formed steel walls framed with dis-similar sheathing we have recently completed a series of component tests on the lateral stiffness of the fasteners-sheathing system to a stud - different sheathing types, environmental conditions and defect conditions were investigated. Complete results are available here.

 

 

 

Design of locally slender hot-rolled steel 

(April 2009)

    The third progress report focused on the cross-section stability of structural steel was just released.  The report details nonlinear finite element analysis of hot-rolled steel structural shapes with locally slender cross-sections. Go here to see all of the reports. Mina Seif (Graduate Res. Asst.) just presented the latest result at the Annual SSRC stability conference held in conjunction with AISC's NASCC Steel Conference. Go here to see all of the presentations and materials.  

 

AISI-COFS field trip to the lab

(Ocotber 2008)

    Nineteen members and guests of the AISI Committee on Framing Standards visited the Thin-walled Structures Lab on 6 October 2008. For more details, go here. This visit was to discuss the AISI project on sheathing braced design of walls, and also included a closer look at the Big Blue Baby, the new multi-axis structural testing rig in our laboratory. 

 

Former student takes position at VA Tech

(August 2008)

    Cris Moen, who recently completed his Ph.D. on buckling of perforated cold-formed steel members with applications to the Direct Strength Method has accepted a position at Virginia Tech. Cris can be reached at cmoen@vt.edu

 

Three new reports released to AISI

(July 2008)

    The draft final report for the Direct Strength Method for Members with Holes, a supplemental report on Analytical Modeling of Rotational Restraint in cold-formed steel framing systems, and a new report on Inelastic Bending of Cold-Formed Steel Members have all been released this month to AISI. These projects will be discussed at the forthcoming AISI-COS meetings in Denver Colorado.  

 

Computational modeling page updated
(July 2008)

    Computational modeling of cold-formed steel is a key research effort of the thin-walled structures research group. Our web page summarizing work in this area has been "under construction" for years, but has recently been updated with a new paper and presentation providing current thinking on this important topic.  

 

New GBT Tool released in Portugal

(July 2008)

    Generalized Beam Theory finally has a user friendly program for your use thanks to the hard work of the research group at the Technical University of Lisbon in Portugal. Bebiano, Pina, Silvestre and Camotim provide their program - GBTUL at their site. We look forward to many interesting comparisong between GBTUL and our own program CUFSM.   

 

the group at lunch, November 2007

(L to R back row: Evelyn, Rachel, Zhanjie, Vahid, Dr.S, Yared, Mina
L to R front row: Luiz, Ying, Cris, Ornella)

Help compile cold-formed steel list

(July 2007)

    Your help is needed. What codes and standards govern the use of cold-formed steel in your country? To help all of us better understand the specifications governing cold-formed steel I am compiling a list of codes and standards used for cold-formed steel around the world. I have created an easy to edit web page so we can all share in the findings, but I need your help compiling the standards used around the world. To use the list, or to add information about your own country please go to http://coldformedsteel.pbwiki.com click on "edit page", the password to edit is "winter". Your help is much appreciated!

 

CUFSM v3.12 Tutorials now live

(May 2008)

    The complete set of tutorials for learning how to use CUFSM, our popular elastic buckling analysis software, has now been updated to the latest version of CUFSM and are available here. (Thanks to Zhanjie Li for updating the old tutorials!).   

 

Structural Steel Cross-section Stability

(April 2008)

    The second progress report focused on the cross-section stability of structural steel was just released.  The report details finite strip analysis and nonlinear finite element analysis of hot-rolled steel structural shapes with locally slender cross-sections. Go here to see all of the reports or download report 2 directly.

     The work was also summarized at the recent AISC Committe on Research meetings and at the SSRC conference held in conjunction with AISC's  NASCC Steel Conference. Go here to see all of the presentations and materials.  

 

5th report on DSM for holes released

(Feb 2008)

    The fifth progress report detailing extension of the Direct Strength Method to cover members with holes has been posted. The report details our recent efforts on simplified methods for predicting elastic buckling of members with holes. Go here to see all of the reports or download: report 5  or presentation 5 directly. 

 

AISI-COFS field trip to JHU on 10 Sept.

(September 2007)

    Twenty-one members of the AISI-COFS attended a research field trip to JHU on 10 September 2007. The field trip focused on three research projects: rotational restraint of sheathing, direct strength method for members with holes, and the design of sheathed walls. Full details are provided here including the final annotated version of the slides from the presentations.  

 

Cross-section stability of structural steel

(June 2007)

    A series of educational tutorials on the cross-section stability of structural steel has recently been added here. These tutorials primarily focus on local and global buckling of a hot-rolled W-section and include: step by step instructions for using finite strip analysis to examine the cross-section stability of hot-rolled steel structural shapes, specific learning objectives for the tutorials, and a set of complementary exercises. In addition a tutorial covering more advanced topics including modal interaction and higher modes in cross-section stability analysis is also provided. (go there)

 

Bio-corner added to web site

(January 2007)

    With all of the excellent and active research in biological applications at Johns Hopkins the thin-walled structures group has several unique collaborations in "bio" related applications. A new set of links and commentary has been added to this site to track this work. Take a look here and let us know what you think. 

 

CUFSM v3.12 released

(December 2006)

    A minor release of CUFSM with bug fixes has been released. The new version (improved from version 3.11) allows users to properly read in older 2.5 and 2.6 files and also provides a correction to the b cross-section property (b is provided to the user, but not employed in calculation.). This release follows from the successful release of version 3.11 in October. 

 

CUTWP New Release (Dec 2006 release)

(December 2006)

    CUTWP is a software tool that provides thin-walled section properties (I, J, Cw, b) as well as classical global buckling solutions for flexural, flexural-torsional, and lateral-torsional buckling. Thanks to our users a bug in the lateral-torsional buckling calculations (b actually) was identified and has now been corrected. The latest version for matlab and standalone are now available. (Note to CUFSM users, the bug in CUTWP is unrelated to CUFSM).

the group at DC United game August 2007

(L to R: Cris, Yared, Mina, Luiz, Vahid)

 

Progress report on DSM for holes released

(July 2007)

    The fourth progress report detailing extension of the Direct Strength Method to cover members with holes has been posted. The report details our recent nonlinear modeling of columns with holes including new methods for determining initial residual stresses and strains in cold-formed steel members, and also looks at several design options for dealing with 'net section' issues in the Direct Strength Method. Go here to see all of the reports. Download: report or presentation 

 

New logo new plans for CFSEI

(March 2007)

    A new logo has just been finalized for CFSEI. This new logo comes as part of the re-branding of the Institute. Professor Schafer served as President of

CFSEI for 2006/7 year, which just ended. During this last year CFSEI developed a new strategic plan and a specific implementation plan funded by the Steel Framing Alliance to meet the objectives in the strategic plan. Also, a full-time Manager, Brian Berger, was hired for the Institute. For more information see www.cfsei.org.  

 

thin-walled structures group, October 2006

(L to R: Luiz, Yared, Vahid, Mina, Dr. S, Cris)

 

 

Progress report on DSM for holes released

(March 2007)

    The third progress report detailing extension of the Direct Strength Method to cover members with holes has been posted. The report details our recent experimental program on columns with holes as well as new work examining existing experiments on beams with holes. Go here to see all of the reports.  

 

Prof. Y.K. Cheung, creater of the finite strip method thanks Prof. Schafer for his participation at Ben Young's Steel Symposium in Hong Kong

 

Hong Kong Symposium

(November 2006)

    Professor Schafer presented the latest developments in the Direct Strength Method at Ben Young's symposium in Hong Kong: Innovative Design of Steel Structures. Pictured above is Professor Schafer with Y.K. Cheung, creator of the finite strip method, and currently special advisor to the Vice-Chancellor of the University of Hong Kong.

 

New Version of CUFSM Released (v3.11)

(October 2006)

    Our popular and free software for the cross-section elastic buckling analysis of thin-walled members using the finite strip method has been significantly updated and is now available both as a compiled standalone version for PCs and a fully open Matlab version for any platform. The new version of CUFSM provides several interface improvements, but also brings the constrained finite strip method, or cFSM, to users for the first time. This new variant of traditional finite strip methods allows users to focus on individual cross-section stability modes in isolation and/or examine the results of general analysis in new detail, through modal decomposition features previously only available with Generalized Beam Theory techniques. Learn more about cFSM here, and download CUFSM here.

 

LGSEA now CFSEI - with Big Plans

(Fall 2006)

    The Light Gauge Steel Engineers Association has renamed itself as the Cold-Formed Steel Engineers Institute, or CFSEI. The new name came out of a recent strategic planning session conducted by the Board. Along with the new name the organization has a new plan and direction for the coming years - learn more about CFSEI's plans through this presentation. Professor Schafer currently serves as President for the CFSEI.

 

Direct Strength Method - MBMA Workshop

(July 2006)

    With the sponsorship of the MBMA a workshop on the Direct Strength Method was held in July of 2006 for MBMA members. The workshop materials are available online here.

 

Direct Strength Method Design Guide

(Summer 2006)

    The Direct Strength Method for the design of cold-formed steel members now has a 170 page design guide, complete with nearly 100 pages of practical examples to help practitioners and students learn more about this new and flexible method for member design of cold-formed steel. The Guide was authored by Professor Schafer through funding by the American Iron and Steel Institute. Purchase a copy of the Guide at AISI or though the Steel Framing Alliance.

 

Schafer named President of LGSEA

(Spring 2006)

    The Light Gauge Steel Engineers Association (LGSEA) recently named Prof. Schafer as President of their organization. With a membership of approximately 800 members the LGSEA strives to serve the technical needs of structural engineers working with cold-formed steel structures. More about the LGSEA is available at their website www.lgsea.com.  

 

New distortional buckling provisions

(March 2006)

    At the most recent AISI-COS cold-formed steel meetings a new design provision to account for the distortional buckling limit state in beams was passed. You can read more about the research that lead to these new provisions in the links to the left. 

 

Global buckling calculations made easy

(December 2005)

    For a number of years now we have made available our finite strip software, CUFSM, for determining the stability of thin-walled member. However, at times, you may only be concerned with global buckling behavior, such as flexural-torsional buckling and not need the more general power of CUFSM. Enter, CUTWP, a program written by Andrew Sarawit that generates section properties and performs classic global buckling calculations. We have recently made CUTWP available in an open source format similar to CUFSM, and enhanced CUTWP so that it can read CUFSM input files. Have fun with the free software!

 

Mid Atlantic Steel Framing Conf.

(May 2005)

    The mid atlantic chapter of the steel framing alliance (MASFA) came together to share technical talks and network. Dr. Schafer introduced the Direct Strength Method of Cold-Formed Steel Design to the attendees. His slides are available here.

 

Final report on beam distortional buckling

(February 2005)

    Our final report on distortional buckling in cold-formed steel beams has been posted. The report provides experimental data for strength prediction in distortional buckling and new findings related to modeling and design for distortional buckling including incorporating the effect of moment gradients and partial restraint. 

 

New Analysis Ideas Released in Report

(September 2004)

    A new research report has been posted that details our novel new method for constraining the finite strip method to produce modal solutions similar to those employed in Generalized Beam Theory (GBT). Updates to CUFSM to allow others to employ this method are in the works. For more details.  

 

Direct Strength Method passes AISI

(January 2004 revision)

    The Direct Strength Method (DSM), an entirely new design method for cold-formed steel that uses member elastic buckling solutions, passed the AISI Committee on Specifications at its July 2003 meetings and has now the language for the final version has been finalized.  Learn more about DSM and get the finalized version, or take a look at the talk  introducing DSM that tied for best presentation at the 2003 Structures Congress. Also, learn more about elastic buckling analysis and  DSM's engine: CUFSM.

 

 

Is the femur a thin-walled structure?

(September 2004)

    In collaboration with  Dr. Tom Beck of the JHU medical school we have been applying finite strip analysis to examine the stability of the human femur. Preliminary work is reported at a recent conference. 

 

Direct Strength Method passes AISI

(January 2004 revision)

    The Direct Strength Method (DSM), an entirely new design method for cold-formed steel that uses member elastic buckling solutions, passed the AISI Committee on Specifications at its July 2003 meetings and has now the language for the final version has been finalized.  Learn more about DSM and get the finalized version, or take a look at the talk  introducing DSM that tied for best presentation at the 2003 Structures Congress. Also, learn more about elastic buckling analysis and  DSM's engine: CUFSM.

 

Former student takes position at UNT

(January 2005)

    Cheng Yu, who recently completed his Ph.D. on distortional buckling of cold-formed steel beams has accepted a position at the University of North Texas. Cheng can be reached at cyu@unt.edu

 

Special Cold-Formed Steel Issue of JSE

(April 2005)

    Based on the efforts of the ASCE-SEI Committee on cold-formed steel a special issue of the Journal of Structural Engineering (JSE) devoted to cold-formed steel research is being prepared. The papers were solicited from the 2004 CCFSS conference, and are currently under review, Professor Schafer is serving as Guest Editor for this issue of JSE.

 

Compendex to Log Stability Conferences

(September 2004)

    Through the efforts of Liz Mengel of the Johns Hopkins Libraries, and the ASCE committee on Cold-Formed Steel, Compendex has agreed to begin logging the conference proceedings for the annual SSRC Stability Conference and the bi-annual UMR CCFSS cold-formed steel specialty conference. 

 

Finite Strip Software is Free! (now v2.6b)

(September 2003 revision)

    CUFSM, our popular and free software for investigating the elastic buckling of arbitrarily shaped, simply supported, thin-walled members  is now available. Extensive online tutorials have been added so that now you can educate yourself about the use of this powerful, but simple, numerical tool in the most efficient manner. Downloads, installation instructions, tutorials, and examples files are all freely available. (go there!). The beta version of CUFSM 2.6 is now out for both Matlab and the standalone version. [JHU Press Release 09.03.2002 (go to article)]

last updated 08/13/10 BWS

webmaster: Ben Schafer, schafer@jhu.edu 

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