Differences between S11 and SP1, S22, SP2, S33, SP3 ?

[Le Chi Hung]

Dear everyone,
 
I have a problem that makes me a curiosity. I have defined the Young's modulus (E) of a concrete block as the modulus will change with the change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The problem is:
 
(1). I made a test with two different USDFLD Subrountines. The first subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33. The second one, I used " Call GETVRM ('SP',  ARRAY..." to get SP1, SP2, SP3. It was because I thought that these S11, S22, S33 and SP11, SP22, SP33 were similar. However, I got correct results with the second subrountine.
 
(2). The same definition I did with a UMAT subrountine (the third subrountine). In UMAT, I defined the Young's modulus that changed as the change of  the stresses by using STRESS(1), STRESS(2), STRESS(3). It was because I also thought that these stress were similar as principle stresses. However, the I got the result is the same as that of the first USDFLD with S11, S22, S33.
 
My questions are:
 
(a) What is the difference between S11 and SP1 for example?
 
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in UMAT subrountine ?
 
Thank you very much,
 
Regards,
Hung

[Non-text portions of this message have been removed]

[Dave Lindeman]

'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.

Regards,

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Le Chi Hung]

Dear Dave,
 
Thank you very much for your teaching.
 
My target is that, I need to get the Principle Stresses, which  are ranged from Initial Principle Stresses to any value that changed during analyzing.
 
I have used the SPRINC utility routine within my UMAT to diagnose by using:
  LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
 
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
 
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very strange values (almost zero or extremely large). Hence, I am wondering whether I used the the SPRINC routine correctly.
 
Would you mind to teach me more detail on that ?
 
Thank you.
 
Yours sincerely,
Hung
 

________________________________
From: Dave Lindeman <***@mmm.com>
To: ***@yahoogroups.com
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?



 

'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.

Regards,

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

[Dave Lindeman]

First, I assume you mean STATEV(1) = PS(1), etc. How are you defining S?

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
Thank you very much for your teaching.
My target is that, I need to get the Principle Stresses, which are
ranged from Initial Principle Stresses to any value that changed
during analyzing.
I have used the SPRINC utility routine within my UMAT to diagnose by
LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very
strange values (almost zero or extremely large). Hence, I am wondering
whether I used the the SPRINC routine correctly.
Would you mind to teach me more detail on that ?
Thank you.
Yours sincerely,
Hung
________________________________
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Le Chi Hung]

Dear Dave,
 
I also tried with STATEV(1)=PS(1). However, I got an error with UMAT compiling. So that I tested with STATEV(1)=PS1...etc and UMAT can run (but this definition is different with that shown in the manual).
 
For S, do you mean the symbol S in PS ? In this case, do I need to define S rather than using LSTR=1  ?
 
As I found from the manual that we can define LSTR=1 to indicate the S in PS as stress (LSTR=2 for strain), as I mentioned in the previous email.
 
Could you give me a suggestion ?
 
Yours sincerely,
Hung
 

________________________________
From: Dave Lindeman <***@mmm.com>
To: ***@yahoogroups.com
Sent: Friday, July 19, 2013 10:57 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?



 

First, I assume you mean STATEV(1) = PS(1), etc. How are you defining S?

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
Thank you very much for your teaching.
My target is that, I need to get the Principle Stresses, which are
ranged from Initial Principle Stresses to any value that changed
during analyzing.
I have used the SPRINC utility routine within my UMAT to diagnose by
LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very
strange values (almost zero or extremely large). Hence, I am wondering
whether I used the the SPRINC routine correctly.
Would you mind to teach me more detail on that ?
Thank you.
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com <mailto:ddlindeman%40mmm.com>>
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

[Dave Lindeman]

No, by "S" I mean the first variable you're passing into SPRINC (CALL
SPRINC(S, PS, etc.)). If you're following the normal naming conventions
within your UMAT, then the stress values are passed in using an array
named "STRESS". Unless you're setting S(i) = STRESS(i) somewhere in
your code, then S is undefined.

Regards,

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
I also tried with STATEV(1)=PS(1). However, I got an error with UMAT
compiling. So that I tested with STATEV(1)=PS1...etc and UMAT can run
(but this definition is different with that shown in the manual).
For S, do you mean the symbol S in PS ? In this case, do I need to
define S rather than using LSTR=1 ?
As I found from the manual that we can define LSTR=1 to indicate the S
in PS as stress (LSTR=2 for strain), as I mentioned in the previous email.
Could you give me a suggestion ?
Yours sincerely,
Hung
________________________________
Sent: Friday, July 19, 2013 10:57 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
First, I assume you mean STATEV(1) = PS(1), etc. How are you defining S?
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
Thank you very much for your teaching.
My target is that, I need to get the Principle Stresses, which are
ranged from Initial Principle Stresses to any value that changed
during analyzing.
I have used the SPRINC utility routine within my UMAT to diagnose by
LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very
strange values (almost zero or extremely large). Hence, I am wondering
whether I used the the SPRINC routine correctly.
Would you mind to teach me more detail on that ?
Thank you.
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com

<mailto:ddlindeman%40mmm.com>>

Post by Le Chi Hung
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Le Chi Hung]

Hello Dave,
 
Thank you very much for your email. I wrote to you several days ago but there was an error with my emails when I sent to our group mail. Hence, those were not accepted to be published. I am sorry about that.
 
With UMAT, when I get stresses, I usually define directly such as : STRESS(1), STRESS(2), STRESS(3)...etc and I don't use any other intermediate variable.
 
Problem is I cannot get the principle stresses in the UMAT by using the rountine SPRINC, even I have tried to test with a simple UMAT for elastic model. If you have an example for the use of  SPRINC rountine in UMAT, for example with the elastic model, could you please share with me ?
 
In addition, I have sucessfully get the principle streeses by using USDFLD subrountine in conjunction with UMAT. However, the result showed somewhat difference with that when I used the model in ABAQUS's library and define as field variable. Thus, I would like to ask is that the principle stress that called by USDFLD in conjunction with UMAT are the same as that called from SPRINC ?
 
Thank you,
Hung
 
 
 


________________________________
From: Dave Lindeman <***@mmm.com>
To: ***@yahoogroups.com
Sent: Monday, July 22, 2013 11:27 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?


 

No, by "S" I mean the first variable you're passing into SPRINC (CALL
SPRINC(S, PS, etc.)). If you're following the normal naming conventions
within your UMAT, then the stress values are passed in using an array
named "STRESS". Unless you're setting S(i) = STRESS(i) somewhere in
your code, then S is undefined.

Regards,

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
I also tried with STATEV(1)=PS(1). However, I got an error with UMAT
compiling. So that I tested with STATEV(1)=PS1...etc and UMAT can run
(but this definition is different with that shown in the manual).
For S, do you mean the symbol S in PS ? In this case, do I need to
define S rather than using LSTR=1 ?
As I found from the manual that we can define LSTR=1 to indicate the S
in PS as stress (LSTR=2 for strain), as I mentioned in the previous email.
Could you give me a suggestion ?
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com <mailto:ddlindeman%40mmm.com>>
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 10:57 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
First, I assume you mean STATEV(1) = PS(1), etc. How are you defining S?
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
Thank you very much for your teaching.
My target is that, I need to get the Principle Stresses, which are
ranged from Initial Principle Stresses to any value that changed
during analyzing.
I have used the SPRINC utility routine within my UMAT to diagnose by
LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very
strange values (almost zero or extremely large). Hence, I am wondering
whether I used the the SPRINC routine correctly.
Would you mind to teach me more detail on that ?
Thank you.
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com

<mailto:ddlindeman%40mmm.com>>

Post by Le Chi Hung
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the Young's
modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11, S22, S33.
The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and SP11,
SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as that
of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2, SP3 in
UMAT subrountine ?
Thank you very much,
Regards,
Hung
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

[Dave Lindeman]

My question was, basically, when you're calling SPRINC, are you using:

CALL SPRINC(STRESS,PS,...)

or:

CALL SPRINC(S,PS,...)?

If you're using the first one, you're OK, because the array "STRESS" is
defined, and contains the values passed in by ABAQUS. If you're using
the second one, then you're not going to get meaningful results because
the array "S" is not defined or initialized.

Regards,

Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Hello Dave,
Thank you very much for your email. I wrote to you several days ago
but there was an error with my emails when I sent to our group
mail. Hence, those were not accepted to be published. I am sorry about
that.
STRESS(1), STRESS(2), STRESS(3)...etc and I don't use any other
intermediate variable.
Problem is I cannot get the principle stresses in the UMAT by using
the rountine SPRINC, even I have tried to test with a simple UMAT for
elastic model. If you have an example for the use of SPRINC rountine
in UMAT, for example with the elastic model, could you please share
with me ?
In addition, I have sucessfully get the principle streeses by using
USDFLD subrountine in conjunction with UMAT. However, the result
showed somewhat difference with that when I used the model in ABAQUS's
library and define as field variable. Thus, I would like to ask is
that the principle stress that called by USDFLD in conjunction with
UMAT are the same as that called from SPRINC ?
Thank you,
Hung
________________________________
Sent: Monday, July 22, 2013 11:27 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
No, by "S" I mean the first variable you're passing into SPRINC (CALL
SPRINC(S, PS, etc.)). If you're following the normal naming conventions
within your UMAT, then the stress values are passed in using an array
named "STRESS". Unless you're setting S(i) = STRESS(i) somewhere in
your code, then S is undefined.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
I also tried with STATEV(1)=PS(1). However, I got an error with UMAT
compiling. So that I tested with STATEV(1)=PS1...etc and UMAT can run
(but this definition is different with that shown in the manual).
For S, do you mean the symbol S in PS ? In this case, do I need to
define S rather than using LSTR=1 ?
As I found from the manual that we can define LSTR=1 to indicate the S
in PS as stress (LSTR=2 for strain), as I mentioned in the previous

email.

Post by Le Chi Hung
Could you give me a suggestion ?
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com

<mailto:ddlindeman%40mmm.com>>

Post by Le Chi Hung
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 10:57 PM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
First, I assume you mean STATEV(1) = PS(1), etc. How are you defining S?
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear Dave,
Thank you very much for your teaching.
My target is that, I need to get the Principle Stresses, which are
ranged from Initial Principle Stresses to any value that changed
during analyzing.
I have used the SPRINC utility routine within my UMAT to diagnose by
LSTR=1 ! To indicate the PS is the principle stress.
CALL SPRINC(S,PS,LSTR,NDI,NSHR)
! Write principle stresses to ODB
STAVE(1) =PS1 ! Write PS1 into OUTPUT file
STAVE(2) =PS2 ! Write PS1 into OUTPUT file
STAVE(3) =PS3 ! Write PS1 into OUTPUT file
However, when I finished the analysis the SDV1, SDV2, SDV3 showed very
strange values (almost zero or extremely large). Hence, I am wondering
whether I used the the SPRINC routine correctly.
Would you mind to teach me more detail on that ?
Thank you.
Yours sincerely,
Hung
________________________________
From: Dave Lindeman <mailto:ddlindeman%40mmm.com

<mailto:ddlindeman%40mmm.com>>

Post by Le Chi Hung
To: mailto:Abaqus%40yahoogroups.com <mailto:Abaqus%40yahoogroups.com>
Sent: Friday, July 19, 2013 6:55 AM
Subject: Re: [Abaqus] Differences between S11 and SP1, S22, SP2, S33, SP3 ?
'S' (and STRESS within the UMAT) are component stresses. 'SP' are the
principal stresses. Within a UMAT, use the SPRINC utility routine to
get the principal stresses.
Regards,
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Post by Le Chi Hung
Dear everyone,
I have a problem that makes me a curiosity. I have defined the

Young's

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modulus (E) of a concrete block as the modulus will change with the
change of principle stresses (Sigma-1, Sigma-2, and Sigma-3). The
(1). I made a test with two different USDFLD Subrountines. The first
subroutine, I used " Call GETVRM ('S', ARRAY..." to get S11,

S22, S33.

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The second one, I used " Call GETVRM ('SP', ARRAY..." to get SP1,
SP2, SP3. It was because I thought that these S11, S22, S33 and

SP11,

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SP22, SP33 were similar. However, I got correct results with the
second subrountine.
(2). The same definition I did with a UMAT subrountine (the third
subrountine). In UMAT, I defined the Young's modulus that changed as
the change of the stresses by using STRESS(1), STRESS(2), STRESS(3).
It was because I also thought that these stress were similar as
principle stresses. However, the I got the result is the same as

that

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of the first USDFLD with S11, S22, S33.
(a) What is the difference between S11 and SP1 for example?
(b) How can I define the principle stresses, such as SP1, SP2,

SP3 in

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UMAT subrountine ?
Thank you very much,
Regards,
Hung
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