Subject: RE: C503: (ACES Special Issue)Finite Element Modeling of Multibody Contact and Its Application to Active Faults From: "Huilin XING" Date: Fri, 28 Sep 2001 16:01:56 +0900 To: "Geoffrey Fox" X-UIDL: 03c23f3b8d021100 X-Mozilla-Status: 0011 X-Mozilla-Status2: 00000000 Received: by mailer.csit.fsu.edu (mbox gcfpc) (with Cubic Circle's cucipop (v1.31 1998/05/13) Sun Oct 14 17:00:25 2001) X-From_: fox@mailer.csit.fsu.edu Sun Oct 14 16:52:47 2001 Return-Path: Delivered-To: gcfpc@csit.fsu.edu Received: from dirac.csit.fsu.edu (dirac.csit.fsu.edu [144.174.128.44]) by mailer.csit.fsu.edu (Postfix) with ESMTP id B6E7723A07 for ; Sun, 14 Oct 2001 16:52:41 -0400 (EDT) Received: from localhost by dirac.csit.fsu.edu (AIX4.2/UCB 8.7) id QAA44736; Sun, 14 Oct 2001 16:52:32 -0400 (EDT) Resent-Message-Id: <200110142052.QAA44736@dirac.csit.fsu.edu> Replied: Fri, 28 Sep 2001 07:23:00 -0400 Replied: "Huilin XING" Delivered-To: fox@csit.fsu.edu Received: from fins.uits.indiana.edu (fins.uits.indiana.edu [129.79.6.185]) by mailer.csit.fsu.edu (Postfix) with ESMTP id 6F34C23A0C for ; Fri, 28 Sep 2001 03:03:18 -0400 (EDT) Received: from mailman.riken.go.jp (mailman.riken.go.jp [134.160.33.1]) by fins.uits.indiana.edu (8.10.1/8.10.1/IUPO) with ESMTP id f8S737D31983 for ; Fri, 28 Sep 2001 02:03:07 -0500 (EST) Received: from earth (rkncic.riken.go.jp [134.160.240.1]) by mailman.riken.go.jp (8.9.3/3.7W) with SMTP id QAA17053 for ; Fri, 28 Sep 2001 16:02:59 +0900 (JST) Message-ID: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPart_000_0000_01C14836.E6020350" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal In-Reply-To: <3B6DBBBF.20304@csit.fsu.edu> X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Resent-To: Geoffrey Fox Resent-Date: Sun, 14 Oct 2001 16:52:30 -0400 Resent-From: Geoffrey Fox Dear Professor Fox, Thank you very much for your email on our manuscript. We have revised it according to the referees' comments and send the revised one to you (in both *.pdf and *.doc format). The responses to the referees' reports are also enclosed here. We are looking forward to the further information about it. Sincerely yours, Huilin ---------------------------------------- Dr. HuiLin Xing Materials Fabrication Lab RIKEN 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, JAPAN Tel: +81-48-467 9319 Fax: +81-48-467-8705 Email: xing@postman.riken.go.jp -----Original Message----- From: Geoffrey Fox [mailto:fox@csit.fsu.edu] Sent: Monday, August 06, 2001 6:34 AM To: H.L. Xing Subject: C503: (ACES Special Issue)Finite Element Modeling of Multibody Contact and Its Application to Active Faults I have pleasure in including referee reports on your ACES paper Please submit a revised version by Sept 30 2001 and include a short memo explaining how you addressed referees' comments. Thank you Referee 1 Report ************************************************************************ The manuscript describes a methodology to simulate static or quasi-static frictional contact between multi-elasto-plastic bodies using a general nonlinear friction law. The approach uses a "node-to-point" contact element strategy in order to overcome convergence problems existing in other methodologies. Interesting results are obtained with the approach which shows that the model can be successfully applied to active faults. However, the manuscript fails to demonstrate the efficiency and stability of the approach. Therefore I recommand the manuscript for publication providing the suggested changes are made. I believe that the paper should be revised in various ways before re-submission. Minor problems with the manuscript are: 1) "in our laboratory" should be replaced by the institution name. 2) The introduction states that the model aims to "further predict earthquake occurence". I suggest removing this statement or rephrasing it into a more general statement such as "the approach may permit study of earthquake prediction". 3) References to other methodologies are required for the statement "it is also well known that it is quite time consuming and also difficult for dynamic-explicit FEM to predict the stress distribution with a high accuracy". 4) Eq. (1) states that when contact occurs the normal contact velocity is null (ie. d(g sub n)/dt = 0 ) this would require explanation since it would appear that for a contact to occur the normal contact velocity must not be zero. 5) Eq. (2) states that (f sup alpha). (n sup alpha) < 0 when a contact occurs, whereas Figure 1 shows otherwise ( (f sup alpha). (n sup alpha) > 0 ). 6) Eq. (3) assumes that g sub n < 0 because the two bodies are in contact, this should be explicitly stated in the text. 7) Eq. (5) f sub m is not defined in the text, and the term sqrt( (f sub m)(f sub m) ) is used in the equation. Do the author(s) mean abs(f sub m) ? 8) Eq. (7) needs more explanation. 9) Figure 6 shows units in mm. Do the author(s) mean m? The dimensions of model also appears to be wrong ( 20038 X 51 X 600 does not appear to correspond to the dimensions of the model shown in Figure 6). Major problems with the manuscript are: 10) Section 5: as stated in the manuscript, one of the goals of this paper is to show the efficiency, stability and usefulness of the proposed algorithm. However the manuscript failed to demonstrate the efficiency and stability of the algorithm. The algorithm utilizes a parallel sparse solver which is the only parallel part of the algorithm (cf. section 5, the contact search and stiffness matrix assembly computations are serial). The only performance estimate is given by Figure 5 which shows computational time vs. numbers of contact nodes. To demonstrate efficiency, a speed-up plot with number of processors, estimate of flops vs. model size, and/or comparison with other algorithms would be required. The stability of the algorithm is not demonstrated in the manuscript. The rate of convergence (number of iterations required) for various problems should be stated and eventually compared with other methodologies to demonstrate stability and efficiency. 11) Section 6: References to the actual analysis and description of the numerical experiment or a more detail analysis is required. Only a few input parameters are given in the text. Enough details should be given so that the experiment may be reproduced. Presentation Changes 12) Figure 6b showing a 3D view of the mesh is not necessary and should be removed. Referee 2 Report ************************************************************************ This is an interesting paper which should be published with some enhancement. Sections 4 and 5 need extension with a deeper discussion of parallel computational structure -- what architecture and programming model do you use. Does method scale to large parallel machines? The presentation -- including english style -- is good.