Dear Khubaib

Try PROMETHEE, TOPSIS or SIMUS

Dear Khubaib 

All MCDM methods are suitable for large number of evaluation criteria, but the selection an appropriate MCDM method or why this method is better than another are depend on your circumstances and MCDM problem.  For example, if the relationships among criteria is important for you you need to use ANP. While, if the calculation time is important for you; you need to avoid use Pairwise comparison methods such as (AHP, ANP, decision matrix, ELECTRE, MACBETH, REMBRANDT, PAPRIKA). for example, in your case,the MCDM problem includes 6 alternatives and 45 criteria, therefore, complete pairwise comparison can be extremely time consuming especially when you have multi-level. 

At the end, none of MCDM methods is perfect and each of them has limitations and benefits. Also, evaluation MCDM methods is different research area and it will make you confused, so I advice you to keep using the method that you select FAHP or I can recommend FSAW method to handle your problem.

I attached two papers that I feel they will help you....

All the best... 

Dear Khubaib

 I  agree with Hamzeh about that you can put as many criteria as you want in any MCDM model, however, depending of your problem, because pair wise comparison may be very time consuming.

It is true that ANP can handle interrelations between criteria, however it cannot work with correlations, therefore, if you have that circumstance, and most probably you do, because the large number of criteria, you cannot use ANP

I also agree with him in the sense that none of the MCDM models is perfect, all have their pitfalls, therefore, you have to select the suitable  model, since not all models are adequate for all type of  problems

Some of the MCDM methods which can be used are Multi-attribute utility theory (MAUT),  analytic hierarchy process (AHP), analytic network process (ANP), Data envelopment analysis (DEA), ELECTRE, PROMETHEE and TOPSIS. 

We have recently worked on a therodynamical approach towards MCDM. The method is simple to impelemt and computationally efficient than TOPSIS. 

Hope this helps.

Article A thermodynamical approach towards group multi-criteria deci...